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Document and Entity Information - shares	9 Months Ended
Document and Entity Information - shares	Sep. 30, 2014	Oct. 31, 2014
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2014
Document Fiscal Year Focus	2014
Document Fiscal Period Focus	Q3
Trading Symbol	EXR
Entity Registrant Name	Extra Space Storage Inc.
Entity Central Index Key	0001289490
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		116,330,711

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2014	Dec. 31, 2013
Assets:
Real estate assets, net	$ 3,954,759	$ 3,636,544
Investments in unconsolidated real estate ventures	86,232	88,125
Cash and cash equivalents	49,216	126,723
Restricted cash	26,205	21,451
Receivables from related parties and affiliated real estate joint ventures	12,283	7,542
Other assets, net	97,200	96,755
Total assets	4,225,895	3,977,140
Liabilities, Noncontrolling Interests and Equity:
Notes payable	1,779,201	1,588,596
Premium on notes payable	4,010	4,948
Exchangeable senior notes	250,000	250,000
Discount on exchangeable senior notes	(13,920)	(16,487)
Notes payable to trusts	119,590	119,590
Lines of credit	40,000
Accounts payable and accrued expenses	73,528	60,601
Other liabilities	39,888	37,997
Total liabilities	2,292,297	2,045,245
Commitments and contingencies
Extra Space Storage Inc. stockholders' equity:
Preferred stock, $0.01 par value, 50,000,000 shares authorized, no shares issued or outstanding
Common stock, $0.01 par value, 500,000,000 shares authorized, 116,033,989 and 115,755,527 shares issued and outstanding at September 30, 2014 and December 31, 2013, respectively	1,160	1,157
Paid-in capital	1,982,612	1,973,159
Accumulated other comprehensive income	3,735	10,156
Accumulated deficit	(248,179)	(226,002)
Total Extra Space Storage Inc. stockholders' equity	1,739,328	1,758,470
Noncontrolling interest represented by Preferred Operating Partnership units, net of $100,000 note receivable	102,818	80,947
Noncontrolling interests in Operating Partnership	90,420	91,453
Other noncontrolling interests	1,032	1,025
Total noncontrolling interests and equity	1,933,598	1,931,895
Total liabilities, noncontrolling interests and equity	$ 4,225,895	$ 3,977,140

Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2014	Dec. 31, 2013
Statement of Financial Position [Abstract]
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	50,000,000	50,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	500,000,000	500,000,000
Common stock, shares issued	116,033,989	115,755,527
Common stock, shares outstanding	116,033,989	115,755,527
Note receivable from noncontrolling interest represented by Preferred Operating Partnership units	$ 100,000	$ 100,000

Condensed Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Revenues:
Property rental	$ 144,669	$ 113,881	$ 415,448	$ 324,144
Tenant reinsurance	15,385	12,294	43,356	34,625
Management fees	7,314	6,936	20,984	19,910
Total revenues	167,368	133,111	479,788	378,679
Expenses:
Property operations	43,294	34,376	129,070	102,275
Tenant reinsurance	2,930	2,873	8,133	6,985
Acquisition related costs	436	2,427	3,885	3,562
General and administrative	13,966	13,943	44,253	40,451
Depreciation and amortization	29,249	23,428	85,895	69,238
Total expenses	89,875	77,047	271,236	222,511
Income from operations	77,493	56,064	208,552	156,168
Gain (loss) on sale of real estate and earnout from prior acquisition	(2,500)	0	(10,285)	800
Loss on extinguishment of debt related to portfolio acquisition	0	(9,153)	0	(9,153)
Interest expense	(20,681)	(16,264)	(60,937)	(51,992)
Non-cash interest expense related to amortization of discount on equity component of exchangeable senior notes	(679)	(834)	(2,004)	(947)
Interest income	186	202	1,167	519
Interest income on note receivable from Preferred Operating Partnership unit holder	1,213	1,213	3,638	3,638
Income before equity in earnings of unconsolidated real estate ventures and income tax expense	55,032	31,228	140,131	99,033
Equity in earnings of unconsolidated real estate ventures	2,777	3,405	7,800	8,942
Equity in earnings of unconsolidated real estate ventures-gain on purchase of joint venture partners' interests	378	0	3,816	2,556
Income tax (expense) benefit	1,006	(2,281)	(5,337)	(7,147)
Net income	59,193	32,352	146,410	103,384
Net income allocated to Preferred Operating Partnership noncontrolling interests	(2,977)	(2,033)	(8,281)	(5,495)
Net income allocated to Operating Partnership and other noncontrolling interests	(1,988)	(1,074)	(4,896)	(2,753)
Net income attributable to common stockholders	$ 54,228	$ 29,245	$ 133,233	$ 95,136
Earnings per common share
Basic	$ 0.47	$ 0.26	$ 1.15	$ 0.86
Diluted	$ 0.47	$ 0.26	$ 1.15	$ 0.85
Weighted average number of shares
Basic	115,726,911	110,827,793	115,606,845	110,624,757
Diluted	121,617,554	115,477,145	121,551,889	115,323,059
Cash dividends paid per common share	$ 0.47	$ 0.40	$ 1.34	$ 1.05

Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Statement of Comprehensive Income [Abstract]
Net income	$ 59,193	$ 32,352	$ 146,410	$ 103,384
Other comprehensive income (loss):
Change in fair value of interest rate swaps	1,834	(2,073)	(6,614)	17,967
Total comprehensive income	61,027	30,279	139,796	121,351
Less: comprehensive income attributable to noncontrolling interests	5,137	2,996	12,984	8,796
Comprehensive income attributable to common stockholders	$ 55,890	$ 27,283	$ 126,812	$ 112,555

Condensed Consolidated Statement of Noncontrolling Interests and Equity - 9 months ended Sep. 30, 2014 - USD ($) $ in Thousands	Total	Series A [Member]	Series B [Member]	Series C [Member]	Common Operating Partnership [Member]	Other [Member]	Par Value [Member]	Paid-in Capital [Member]	Accumulated Other Comprehensive Income [Member]	Accumulated Deficit [Member]
Balances at Dec. 31, 2013	$ 1,931,895	$ 30,202	$ 33,568	$ 17,177	$ 91,453	$ 1,025	$ 1,157	$ 1,973,159	$ 10,156	$ (226,002)
Balances (in shares) at Dec. 31, 2013	115,755,527						115,755,527
Issuance of common stock upon the exercise of options	$ 2,717						$ 2	2,715
Issuance of common stock upon the exercise of options (in shares)							186,465
Restricted stock grants issued	1						$ 1
Restricted stock grants issued (in shares)							113,570
Restricted stock grants cancelled (in shares)							(21,573)
Compensation expense related to stock-based awards	3,855							3,855
Issuance of Operating Partnership units in conjunction with portfolio acquisition	22,117		8,334	13,783
Net income	146,410	5,429	1,758	1,094	4,889	7				133,233
Other comprehensive income	(6,614)	(36)			(157)				(6,421)
Tax effect from vesting of restricted stock grants and stock option exercises	2,883							2,883
Distributions to Operating Partnership units held by noncontrolling interests	(14,256)	(5,639)	(1,758)	(1,094)	(5,765)
Dividends paid on common stock at $1.34 per share	(155,410)									(155,410)
Balances at Sep. 30, 2014	$ 1,933,598	$ 29,956	$ 41,902	$ 30,960	$ 90,420	$ 1,032	$ 1,160	$ 1,982,612	$ 3,735	$ (248,179)
Balances (in shares) at Sep. 30, 2014	116,033,989						116,033,989

Condensed Consolidated Statement of Noncontrolling Interests and Equity (Parenthetical) - $ / shares	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Statement of Stockholders' Equity [Abstract]
Dividends paid on common stock, per share	$ 0.47	$ 0.40	$ 1.34	$ 1.05

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
Cash flows from operating activities:
Net income	$ 146,410	$ 103,384
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	85,895	69,238
Amortization of deferred financing costs	4,955	4,198
Loss on earnout related to prior acquisition	2,500
Loss on extinguishment of debt related to portfolio acquisition	0	9,153
Non-cash interest expense related to amortization of discount on equity component of exchangeable senior notes	2,004	947
Non-cash interest benefit related to amortization of premium on notes payable	(2,350)	(983)
Compensation expense related to stock-based awards	3,855	3,654
Gain on purchase of joint venture partners' interests	(3,438)	(2,556)
Distributions from unconsolidated real estate ventures in excess of earnings	3,989	3,538
Changes in operating assets and liabilities:
Receivables from related parties and affiliated real estate joint ventures	(434)	891
Other assets	467	(1,303)
Accounts payable and accrued expenses	12,927	5,949
Other liabilities	(216)	2,474
Net cash provided by operating activities	256,564	198,584
Cash flows from investing activities:
Acquisition of real estate assets	(328,235)	(82,949)
Development and redevelopment of real estate assets	(11,288)	(3,941)
Proceeds from sale of real estate assets		889
Investments in unconsolidated real estate ventures		(1,126)
Change in restricted cash	(4,754)	(5,827)
Purchase of notes receivable	(9,028)
Issuance of notes receivable		(5,000)
Purchase of equipment and fixtures	(3,636)	(2,349)
Net cash used in investing activities	(356,941)	(100,303)
Cash flows from financing activities:
Net proceeds from the issuance of exchangeable senior notes		246,250
Proceeds from notes payable and lines of credit	505,957	364,855
Principal payments on notes payable and lines of credit	(312,287)	(532,348)
Deferred financing costs	(3,851)	(6,135)
Redemption of Operating Partnership units held by noncontrolling interest		(41)
Net proceeds from exercise of stock options	2,717	5,876
Dividends paid on common stock	(155,410)	(116,712)
Distributions to noncontrolling interests	(14,256)	(9,112)
Net cash provided by (used in) financing activities	22,870	(47,367)
Net (decrease) increase in cash and cash equivalents	(77,507)	50,914
Cash and cash equivalents, beginning of the period	126,723	30,785
Cash and cash equivalents, end of the period	49,216	81,699
Supplemental schedule of cash flow information
Interest paid	55,694	46,360
Income taxes paid	3,237	1,626
Tax effect from vesting of restricted stock grants and option exercises
Other assets	2,883	3,147
Paid-in capital	(2,883)	(3,147)
Acquisitions of real estate assets
Real estate assets, net	60,465	210,372
Notes payable assumed	(38,347)	(7,122)
Notes payable assumed and immediately defeased		(98,960)
Value of Operating Partnership units issued	$ (22,118)	(102,039)
Receivables from related parties and affiliated real estate joint ventures		$ (2,251)

Organization

9 Months Ended

Sep. 30, 2014

Accounting Policies [Abstract]

Organization

1.	ORGANIZATION

Extra Space Storage Inc. (the “Company”) is a fully-integrated, self-administered and self-managed real estate investment trust (“REIT”), formed as a Maryland corporation on April 30, 2004, to own, operate, manage, acquire, develop and redevelop professionally managed self-storage facilities located throughout the United States. The Company continues the business of Extra Space Storage LLC and its subsidiaries, which had engaged in the self-storage business since 1977. The Company’s interest in its properties is held through its operating partnership, Extra Space Storage LP (the “Operating Partnership”), which was formed on May 5, 2004. The Company’s primary assets are general partner and limited partner interests in the Operating Partnership. This structure is commonly referred to as an umbrella partnership REIT (“UPREIT”). The Company has elected to be taxed as a REIT under the Internal Revenue Code of 1986, as amended. To the extent the Company continues to qualify as a REIT, it will not be subject to tax, with certain limited exceptions, on the taxable income that is distributed to its stockholders.

The Company invests in self-storage facilities by acquiring wholly-owned facilities or by acquiring an equity interest in real estate entities. At September 30, 2014, the Company had direct and indirect equity interests in 810 operating storage facilities. In addition, the Company managed 271 properties for third parties, bringing the total number of operating properties which it owns and/or manages to 1,081. These properties are located in 35 states, Washington, D.C. and Puerto Rico.

The Company operates in three distinct segments: (1) rental operations; (2) tenant reinsurance; and (3) property management, acquisition and development. The rental operations activities include rental operations of self-storage facilities in which we have an ownership interest. No single tenant accounts for more than 5% of rental income. Tenant reinsurance activities include the reinsurance of risks relating to the loss of goods stored by tenants in the Company’s self-storage facilities. The Company’s property management, acquisition and development activities include managing, acquiring, developing and selling self-storage facilities.

Basis of Presentation

9 Months Ended

Sep. 30, 2014

Accounting Policies [Abstract]

Basis of Presentation

2.	BASIS OF PRESENTATION

The accompanying unaudited condensed consolidated financial statements of the Company are presented on the accrual basis of accounting in accordance with U.S. generally accepted accounting principles (“GAAP”) for interim financial information, and in accordance with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they may not include all of the information and footnotes required by GAAP for complete financial statements. In the opinion of management, all adjustments (including normal recurring accruals) considered necessary for a fair presentation have been included. Operating results for the nine months ended September 30, 2014, are not necessarily indicative of results that may be expected for the year ending December 31, 2014. The condensed consolidated balance sheet as of December 31, 2013 has been derived from the Company’s audited financial statements as of that date, but does not include all of the information and footnotes required by GAAP for complete financial statements. For further information refer to the consolidated financial statements and footnotes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2013, as filed with the Securities and Exchange Commission.

Reclassifications

Certain amounts in the Company’s 2013 consolidated financial statements and supporting note disclosures have been reclassified to conform to the current period presentation. Such reclassifications did not impact previously reported net income or accumulated deficit.

Recently Issued Accounting Standards

In May 2014, the Financial Accounting Standards Board issued Accounting Standards Update (“ASU”) 2014-09, “Revenue from Contracts with Customers” (“ASU 2014-09”). ASU 2014-09 amends the guidance for revenue recognition to replace numerous, industry-specific requirements and converges areas under this topic with those of the International Financial Reporting Standards. ASU 2014-09 outlines a five-step process for customer contract revenue recognition that focuses on transfer of control, as opposed to transfer of risk and rewards. The amendment also requires enhanced disclosures regarding the nature, amount, timing and uncertainty of revenues and cash flows from contracts with customers. ASU 2014-09 is effective for reporting periods beginning after December 15, 2016, and early adoption is prohibited. Entities can transition to the standard either retrospectively or as a cumulative-effect adjustment as of the date of adoption. Management is currently assessing the impact of the adoption of ASU 2014-09 on the Company’s condensed consolidated financial statements.

Fair Value Disclosures

9 Months Ended

Sep. 30, 2014

Fair Value Disclosures [Abstract]

Fair Value Disclosures

3.	FAIR VALUE DISCLOSURES

Derivative Financial Instruments

Currently, the Company uses interest rate swaps to manage its interest rate risk. The valuation of these instruments is determined using widely accepted valuation techniques, including discounted cash flow analysis on the expected cash flows of each derivative. This analysis reflects the contractual terms of the derivatives, including the period to maturity, and uses observable market-based inputs, including interest rate curves. The fair values of interest rate swaps are determined using the market standard methodology of netting the discounted future fixed cash payments and the discounted expected variable cash receipts. The variable cash receipts are based on an expectation of future interest rates (forward curves) derived from observable market interest rate forward curves.

The Company incorporates credit valuation adjustments to appropriately reflect both its own nonperformance risk and the respective counterparty’s nonperformance risk in the fair value measurements. In adjusting the fair value of its derivative contracts for the effect of nonperformance risk, the Company has considered the impact of netting and any applicable credit enhancements, such as collateral postings, thresholds, mutual puts and guarantees. In conjunction with the Financial Accounting Standards Board’s fair value measurement guidance, the Company made an accounting policy election to measure the credit risk of its derivative financial instruments that are subject to master netting agreements on a net basis by counterparty portfolio.

Although the Company has determined that the majority of the inputs used to value its derivatives fall within Level 2 of the fair value hierarchy, the credit valuation adjustments associated with its derivatives utilize Level 3 inputs, such as estimates of current credit spreads to evaluate the likelihood of default by the Company and its counterparties. However, as of September 30, 2014, the Company had assessed the significance of the impact of the credit valuation adjustments on the overall valuation of its derivative positions and determined that the credit valuation adjustments were not significant to the overall valuation of its derivatives. As a result, the Company determined that its derivative valuations in their entirety were classified in Level 2 of the fair value hierarchy.

The table below presents the Company’s assets and liabilities measured at fair value on a recurring basis as of September 30, 2014, aggregated by the level in the fair value hierarchy within which those measurements fall.


				Fair Value Measurements at Reporting Date Using
Description	September 30, 2014			Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)			Significant Unobservable Inputs (Level 3)
Other assets—Cash Flow Hedge Swap Agreements	$	7,317		$	—	$	7,317		$	—
Other liabilities—Cash Flow Hedge Swap Agreements	$	(1,818	)	$	—	$	(1,818	)	$	—

There were no transfers of assets and liabilities between Level 1 and Level 2 during the nine months ended September 30, 2014. The Company did not have any significant assets or liabilities that are re-measured on a recurring basis using significant unobservable inputs as of September 30, 2014 or December 31, 2013.

Assets and Liabilities Measured at Fair Value on a Nonrecurring Basis

Long-lived assets held for use are evaluated for impairment when events or circumstances indicate there may be impairment. The Company reviews each self-storage facility at least annually to determine if any such events or circumstances have occurred or exist. The Company focuses on facilities where occupancy and/or rental income have decreased by a significant amount. For these facilities, the Company determines whether the decrease is temporary or permanent, and whether the facility will likely recover the lost occupancy and/or revenue in the short term. In addition, the Company carefully reviews facilities in the lease-up stage and compares actual operating results to original projections.

When the Company determines that an event that may indicate impairment has occurred, the Company compares the carrying value of the related long-lived assets to the undiscounted future net operating cash flows attributable to the assets. An impairment loss is recorded if the net carrying value of the assets exceeds the undiscounted future net operating cash flows attributable to the assets. The impairment loss recognized equals the excess of net carrying value over the related fair value of the assets.

When real estate assets are identified by management as held for sale, the Company discontinues depreciating the assets and estimates the fair value of the assets, net of selling costs. If the estimated fair value, net of selling costs, of the assets that have been identified as held for sale is less than the net carrying value of the assets, a valuation allowance is established. The operations of assets held for sale or sold during the period are generally presented as discontinued operations for all periods presented.

The Company assesses whether there are any indicators that the value of its investments in unconsolidated real estate ventures may be impaired annually and when events or circumstances indicate there may be impairment. An investment is impaired if management’s estimate of the fair value of the investment is less than its carrying value. To the extent impairment has occurred, and is considered to be other than temporary, the loss is measured as the excess of the carrying amount over the fair value of the investment.

In connection with the Company’s acquisition of self-storage facilities, the purchase price is allocated to the tangible and intangible assets and liabilities acquired based on their fair values, which are estimated using significant unobservable inputs. The value of the tangible assets, consisting of land and buildings, is determined as if vacant. Intangible assets, which represent the value of existing tenant relationships, are recorded at their fair values based on the avoided cost to replace the current leases. The Company measures the value of tenant relationships based on the rent lost due to the amount of time required to replace existing customers, which is based on the Company’s historical experience with turnover in its facilities. Debt assumed as part of an acquisition is recorded at fair value based on current interest rates compared to contractual rates. Acquisition-related transaction costs are expensed as incurred.

Fair Value of Financial Instruments

The carrying values of cash and cash equivalents, restricted cash, receivables, other financial instruments included in other assets, accounts payable and accrued expenses, variable-rate notes payable, lines of credit and other liabilities reflected in the condensed consolidated balance sheets at September 30, 2014 and December 31, 2013 approximate fair value.

The fair value of the Company’s note receivable from Preferred Operating Partnership unit holders was based on the discounted estimated future cash flows of the note (categorized within Level 3 of the fair value hierarchy); the discount rate used approximated the current market rate for loans with similar maturities and credit quality. The fair values of the Company’s fixed-rate notes payable and notes payable to trusts were estimated using the discounted estimated future cash payments to be made on such debt (categorized within Level 3 of the fair value hierarchy); the discount rates used approximated current market rates for loans, or groups of loans, with similar maturities and credit quality. The fair value of the Company’s exchangeable senior notes was estimated using an average market price for similar securities obtained from a third party.

The fair values of the Company’s fixed-rate assets and liabilities were as follows for the periods indicated:


	September 30, 2014				December 31, 2013
	Fair Value		Carrying Value		Fair Value		Carrying Value
Note receivable from Preferred Operating Partnership unit holders	$	103,667	$	100,000	$	103,491	$	100,000
Fixed rate notes payable and notes payable to trusts	$	1,318,359	$	1,294,510	$	1,365,290	$	1,368,885
Exchangeable senior notes	$	259,843	$	250,000	$	251,103	$	250,000

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Earnings Per Common Share

9 Months Ended

Sep. 30, 2014

Earnings Per Share [Abstract]

Earnings Per Common Share

4.	EARNINGS PER COMMON SHARE

Basic earnings per common share is computed using the two-class method by dividing net income attributable to common stockholders by the weighted average number of common shares outstanding during the period. All outstanding unvested restricted stock awards contain rights to non-forfeitable dividends and participate in undistributed earnings with common stockholders; accordingly, they are considered participating securities that are included in the two-class method. Diluted earnings per common share measures the performance of the Company over the reporting period while giving effect to all potential common shares that were dilutive and outstanding during the period. The denominator includes the weighted average number of basic shares and the number of additional common shares that would have been outstanding if the potential common shares that were dilutive had been issued, and is calculated using either the two-class, treasury stock or as if-converted method, whichever is most dilutive. Potential common shares are securities (such as options, convertible debt, Series A Participating Redeemable Preferred Units (“Series A Units”), Series B Redeemable Preferred Units (“Series B Units”), Series C Convertible Redeemable Preferred Units (“Series C Units”) and common Operating Partnership units (“OP Units”)) that do not have a current right to participate in earnings of the Company but could do so in the future by virtue of their option, redemption or conversion right. In computing the dilutive effect of convertible securities, net income is adjusted to add back any changes in earnings in the period associated with the convertible security. The numerator also is adjusted for the effects of any other non-discretionary changes in income or loss that would result from the assumed conversion of those potential common shares. In computing diluted earnings per common share, only potential common shares that are dilutive (those that reduce earnings per common share) are included. For the three months ended September 30, 2014 and 2013, options to purchase approximately 29,547 and 51,036 shares of common stock, respectively, and for the nine months ended September 30, 2014 and 2013, options to purchase approximately 27,045 and 43,273 shares of common stock, respectively, were excluded from the computation of earnings per common share as their effect would have been anti-dilutive.

The Operating Partnership had $250,000 of its 2.375% Exchangeable Senior Notes due 2033 (the “Notes”) issued and outstanding as of September 30, 2014. The Notes could potentially have a dilutive effect on the Company’s earnings per common share calculations. The Notes are exchangeable by holders into shares of the Company’s common stock under certain circumstances per the terms of the indenture governing the Notes. The exchange price of the Notes was $55.62 per share as of September 30, 2014, and could change over time as described in the indenture. The Company has irrevocably agreed to pay only cash for the accreted principal amount of the Notes relative to its exchange obligations, but retained the right to satisfy the exchange obligation in excess of the accreted principal amount in cash and/or common stock. Though the Company has retained that right, Accounting Standards Codification (“ASC”) 260, “Earnings per Share,” requires an assumption that shares would be used to pay the exchange obligation in excess of the accreted principal amount, and requires that those shares be included in the Company’s calculation of weighted average common shares outstanding for the diluted earnings per common share computation. For the three and nine months ended September 30, 2014, no shares related to the Notes were included in the computation for diluted earnings per common share as the per share price of the Company’s common stock during this period did not exceed the exchange price.

For the purposes of computing the diluted impact on earnings per common share of the potential exchange of Series A Units for common shares upon redemption, where the Company has the option to redeem in cash or shares and where the Company has stated the positive intent and ability to settle at least $115,000 of the instrument in cash (or net settle a portion of the Series A Units against the related outstanding note receivable), only the amount of the instrument in excess of $115,000 is considered in the calculation of shares contingently issuable for the purposes of computing diluted earnings per common share as allowed by ASC 260-10-45-46.

For the purposes of computing the diluted impact on earnings per common share of the potential exchange of Series B Units for common shares upon redemption, where the Company has the option to redeem in cash or shares and where the Company has the ability to settle the redemption in shares, the Company divided the total weighted value of the Series B Units outstanding as of September 30, 2014 of $39,094 by the average closing price of the Company’s common stock for the nine months ended September 30, 2014 of $50.29 per share. The resulting 777,364 shares were excluded from the computation of earnings per common share as their effect would have been anti-dilutive.

For the purposes of computing the diluted impact on earnings per common share of the potential exchange of Series C Units for common shares upon redemption, where the Company has the option to redeem in cash or shares and where the Company has the ability to settle the redemption in shares, the Company divided the total weighted value of the Series C Units outstanding as of September 30, 2014 of $24,080 by the average closing price of the Company’s common stock for the nine months ended September 30, 2014 of $50.29 per share. The resulting 478,824 shares were excluded from the computation of earnings per common share as their effect would have been anti-dilutive.

The computation of earnings per common share was as follows for the periods presented:


	For the Three Months Ended September 30,						For the Nine Months Ended September 30,
	2014			2013			2014			2013
Net income attributable to common stockholders	$	54,228		$	29,245		$	133,233		$	95,136
Earnings and dividends allocated to participating securities		(125	)		(143	)		(366	)		(390	)

Earnings for basic computations		54,103			29,102			132,867			94,746

Earnings and dividends allocated to participating securities		125			—			366			—
Income allocated to noncontrolling interest—Preferred Operating Partnership (Series A Units) and Operating Partnership		3,875			2,757			10,318			7,875
Fixed component of income allocated to noncontrolling interest—Preferred Operating Partnership (Series A Units)		(1,438	)		(1,438	)		(4,313	)		(4,313	)

Net income for diluted computations	$	56,665		$	30,421		$	139,238		$	98,308

Weighted average common shares outstanding:
Average number of common shares outstanding—basic		115,726,911			110,827,793			115,606,845			110,624,757
Series A Units		989,980			—			989,980			—
Common OP Units		4,334,118			4,346,618			4,334,118			4,346,618
Unvested restricted stock awards included for treasury stock method		294,616			—			321,346			—
Dilutive stock options		271,929			302,734			299,600			351,684

Average number of common shares outstanding—diluted		121,617,554			115,477,145			121,551,889			115,323,059

Earnings per common share
Basic	$	0.47		$	0.26		$	1.15		$	0.86
Diluted	$	0.47		$	0.26		$	1.15		$	0.85

Property Acquisitions and Dispositions

9 Months Ended

Sep. 30, 2014

Business Combinations [Abstract]

Property Acquisitions and Dispositions

5.	PROPERTY ACQUISITIONS AND DISPOSITIONS

The following table summarizes the Company’s acquisitions of operating properties for the nine months ended September 30, 2014, and does not include purchases of raw land or improvements made to existing assets:


					Consideration Paid																	Acquisition Date Fair Value
Property Location	Number of Properties		Date of Acquisition		Total		Cash Paid		Loan Assumed		Non-cash gain		Previous equity interest		Net Liabilities/ (Assets) Assumed			Value of OP Units Issued		Number of OP Units Issued		Land		Building		Intangible		Closing costs - expensed		Notes
Virginia		17		1/7/2014	$	200,588	$	200,525	$	—	$	—	$	—	$	63		$	—		—	$	53,878	$	142,840	$	2,973	$	897
Texas		1		2/5/2014		14,191		14,152		—		—		—		39			—		—		1,767		12,368		38		18
California		1		3/4/2014		7,000		6,974		—		—		—		26			—		—		2,150		4,734		113		3		(1)
Connecticut		1		3/17/2014		15,138		15,169		—		—		—		(31	)		—		—		1,072		14,028		—		38
Alabama		1		3/20/2014		13,813		13,752		—		—		—		61			—		—		2,381		11,224		200		8
Georgia		1		4/3/2014		23,649		15,158		—		—		—		157			8,334		333,360		2,961		19,819		242		627
Florida		1		4/15/2014		10,186		10,077		—		—		—		109			—		—		1,640		8,358		149		39
California		3		4/25/2014		35,275		2,726		19,111		3,438		129		(580	)		10,451		226,285		6,853		27,666		579		177		(2)
Washington		1		4/30/2014		4,388		4,388		—		—		—		—			—		—		437		3,808		102		41
California		1		5/28/2014		17,614		294		14,079		—		—		(92	)		3,333		69,735		4,707		12,604		265		38
North Carolina		1		6/18/2014		7,310		7,307		—		—		—		3			—		—		2,940		4,265		93		12
Georgia		1		8/6/2014		11,337		11,290		—		—		—		47			—		—		1,132		10,080		111		14
Texas		1		8/8/2014		11,246		6,134		5,157		—		—		(45	)		—		—		1,047		9,969		181		49
Florida		1		9/3/2014		4,259		4,225		—		—		—		34			—		—		529		3,604		81		45

2014 Totals		32			$	375,994	$	312,171	$	38,347	$	3,438	$	129	$	(209	)	$	22,118		629,380	$	83,494	$	285,367	$	5,127	$	2,006

(1)

This property was owned by Spencer F. Kirk, the Company’s Chief Executive Officer, and Kenneth M. Woolley, the Company’s Executive Chairman. The Company acquired the building on March 4, 2014. In a separate transaction on March 5, 2014, the Company acquired the land for $2,150 from a third party unrelated to the Company’s executives and terminated the existing ground lease.

(2)

The Company previously held no equity interest in two of the three properties acquired. The Company acquired its joint venture partner’s 60% interest in an existing joint venture which held one property in California, resulting in full ownership by the Company. Prior to the acquisition date, the Company accounted for its 40% interest in this joint venture as an equity method investment. The total acquisition date fair value of the previous equity interest was approximately $3,567 and is included as consideration transferred. The Company recognized a non-cash gain of $3,438 as a result of remeasuring its prior equity interest in this joint venture held before the acquisition. The three properties were acquired in exchange for approximately $2,726 of cash and 226,285 Series C Units valued at $10,451.

On August 29, 2013, the Operating Partnership completed the purchase of 19 out of 20 self-storage facilities affiliated with All Aboard Mini Storage, all of which are located in California. On September 26, 2013, the Operating Partnership completed the purchase of the remaining facility. These properties were acquired in exchange for $100,876 in cash (including $98,960 of debt assumed and immediately defeased at closing), 1,342,727 Series B Units valued at $33,568 and 1,448,108 common OP Units valued at $62,341. In accordance with ASC 805, “Business Combinations,” the assumed debt was recorded at its fair value as of the closing date. The difference between the price paid to extinguish the debt, which included $9,153 of defeasance costs, and the carrying value of the debt was recorded as loss on extinguishment of debt related to portfolio acquisition on the Company’s condensed consolidated statement of operations.

On May 16, 2013, the Company sold a property located in New York for $950. No gain or loss was recorded as a result of the sale.

Gain (Loss) on Sale of Real Estate and Earnout from Prior Acquisition

9 Months Ended

Sep. 30, 2014

Text Block [Abstract]

Gain (Loss) on Sale of Real Estate and Earnout from Prior Acquisition

6.	GAIN (LOSS) ON SALE OF REAL ESTATE AND EARNOUT FROM PRIOR ACQUISITIONS

During 2011, the Company acquired a self-storage property located in Florida. As part of this acquisition, the Company agreed to make an additional cash payment to the sellers if the net rental income generated by the acquired property exceeded a specified amount for any twelve-month period prior to June 30, 2015. At the time of acquisition, the Company believed that it was unlikely that any significant payment would be made as a result of this earnout provision. Based on the recent and projected net rental income of this property, the Company estimated that an earnout payment of $2,500 will be due to the seller. This amount is included in Gain (loss) on sale of real estate and earnout from prior acquisitions on the Company’s condensed consolidated statements of operations.

During 2012, the Company acquired a portfolio of ten self-storage properties located in New York and New Jersey. As part of this acquisition, the Company agreed to make an additional cash payment to the sellers if the properties acquired exceeded a specified amount of net rental income after two years. At the time of acquisition, the Company believed that it was unlikely that any significant payment would be made as a result of this earnout provision. The rental growth of the properties has been higher than expected, resulting in a payment to the sellers of $7,785. This amount is included in Gain (loss) on sale of real estate and earnout from prior acquisitions on the Company’s condensed consolidated statements of operations.

In June 2013, the Company recorded a gain of $800 due to the condemnation of a portion of land at one self-storage property in California that resulted from eminent domain.

Variable Interests

9 Months Ended

Sep. 30, 2014

Equity Method Investments and Joint Ventures [Abstract]

Variable Interests

7.	VARIABLE INTERESTS

The Company has an interest in one unconsolidated joint venture with an unrelated third party which is a variable interest entity (“VIE”). The Company holds an 18% equity interest and a 50% profit interest in the VIE joint venture (“VIE JV”), and has 50% of the voting rights in the VIE JV. Qualification as a VIE was based on the determination that the equity investment at risk for this joint venture was not sufficient based on a qualitative and quantitative analysis performed by the Company. The Company performed a qualitative analysis for the joint venture to determine which party was the primary beneficiary. The Company determined that since the powers to direct the activities most significant to the economic performance of the entity are shared equally by the Company and its joint venture partner, there is no primary beneficiary. Accordingly, the interest is recorded using the equity method.

The VIE JV owns a single self-storage property. This joint venture is financed through a combination of (1) equity contributions from the Company and its joint venture partner and (2) amounts payable to the Company. The amounts payable to the Company consist of expenses paid on behalf of the joint venture by the Company as manager and mortgage notes payable to the Company. The Company performs management services for the VIE JV in exchange for a management fee of approximately 6% of cash collected by the property. The Company completed the purchase of the VIE JV’s mortgage loan on April 3, 2014. The mortgage notes payable are in default as of September 30, 2014. Except as disclosed, the Company has not provided financial or other support during the periods presented to the VIE JV that it was not previously contractually obligated to provide.

The Company’s maximum exposure to loss for this joint venture as of September 30, 2014 is the total of the amounts payable to the Company and the Company’s investment balance in the joint venture. The Company believes that the risk of incurring a material loss as a result of its investment in the property is unlikely and, therefore, no liability has been recorded. Also, repossessing and/or selling the self-storage facility and land that collateralize the amounts payable to the Company could provide funds sufficient to reimburse the Company.

The following table compares the liability balance and the maximum exposure to loss related to the Company’s VIE JV as of September 30, 2014:


	Liability Balance		Investment Balance			Amounts Payable to the Company		Maximum Exposure to Loss		Difference
Extra Space of Sacramento One LLC	$	—	$	(1,232	)	$	10,726	$	9,494	$	(9,494	)

The Operating Partnership has three wholly-owned unconsolidated subsidiaries (“Trust,” “Trust II” and “Trust III,” together, the “Trusts”) that have issued trust preferred securities to third parties and common securities to the Operating Partnership. The proceeds from the sale of the preferred and common securities were loaned in the form of notes to the Operating Partnership. The Trusts are VIEs because the holders of the equity investment at risk (the trust preferred securities) do not have the power to direct the activities of the entities that most significantly affect the entities’ economic performance because of their lack of voting or similar rights. Because the Operating Partnership’s investment in the Trusts’ common securities was financed directly by the Trusts as a result of its loan of the proceeds to the Operating Partnership, that investment is not considered an equity investment at risk. The Operating Partnership’s investment in the Trusts is not a variable interest because equity interests are variable interests only to the extent that the investment is considered to be at risk, and therefore the Operating Partnership cannot be the primary beneficiary of the Trusts. Since the Company is not the primary beneficiary of the Trusts, they have not been consolidated. A debt obligation has been recorded in the form of notes for the proceeds as discussed above, which are owed to the Trusts. The Company has also included its investment in the Trusts’ common securities in other assets on the condensed consolidated balance sheets.

The Company has not provided financing or other support during the periods presented to the Trusts that it was not previously contractually obligated to provide. The Company’s maximum exposure to loss as a result of its involvement with the Trusts is equal to the total amount of the notes discussed above less the amounts of the Company’s investments in the Trusts’ common securities. The net amount is the notes payable that the Trusts owe to third parties for their investments in the Trusts’ preferred securities.

Following is a tabular comparison of the liabilities the Company has recorded as a result of its involvement with the Trusts to the maximum exposure to loss the Company is subject to as a result of such involvement as of September 30, 2014:


	Notes payable to Trusts		Investment Balance		Maximum exposure to loss		Difference
Trust	$	36,083	$	1,083	$	35,000	$	—
Trust II		42,269		1,269		41,000		—
Trust III		41,238		1,238		40,000		—

	$	119,590	$	3,590	$	116,000	$	—

The Company had no consolidated VIEs during the nine months ended September 30, 2014.

Derivatives

9 Months Ended

Sep. 30, 2014

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Derivatives

8.	DERIVATIVES

The Company is exposed to certain risks arising from both its business operations and economic conditions. The Company principally manages its exposures to a wide variety of business and operational risks through management of its core business activities. The Company manages economic risks, including interest rate, liquidity and credit risk, primarily by managing the amount, sources and duration of its debt funding and by using derivative financial instruments. Specifically, the Company enters into derivative financial instruments to manage exposure that arises from business activities that result in the receipt or payment of future known and uncertain cash amounts, the value of which are determined by interest rates. The Company’s derivative financial instruments are used to manage differences in the amount, timing and duration of the Company’s known or expected cash receipts and its known or expected cash payments principally related to the Company’s investments and borrowings.

Cash Flow Hedges of Interest Rate Risk

The Company’s objectives in using interest rate derivatives are to add stability to interest expense and to manage its exposure to interest rate movements. To accomplish these objectives, the Company primarily uses interest rate swaps as part of its interest rate risk management strategy. Interest rate swaps designated as cash flow hedges involve the receipt of variable amounts from a counterparty in exchange for the Company making fixed-rate payments over the life of the agreements without exchange of the underlying notional amount.

The effective portion of changes in the fair value of derivatives designated and that qualify as cash flow hedges is recorded in accumulated other comprehensive income (“OCI”) and is subsequently reclassified into earnings in the period that the hedged forecasted transaction affects earnings. A portion of these changes is excluded from accumulated other comprehensive income as it is allocated to noncontrolling interests. During the three and nine months ended September 30, 2014 and 2013, such derivatives were used to hedge the variable cash flows associated with existing variable-rate debt.

The following table summarizes the terms of the Company’s 20 derivative financial instruments as of September 30, 2014:


Hedge Product	Current Notional Amounts	Strike	Effective Dates	Maturity Dates
Swap Agreements	$4,687 - $95,004	2.79% - 6.12%	11/2/2009 - 1/1/2014	11/1/2014 - 4/1/2021

Fair Values of Derivative Instruments

The table below presents the fair value of the Company’s derivative financial instruments as well as their classification on the condensed consolidated balance sheets:


	Asset (Liability) Derivatives
	September 30, 2014				December 31, 2013
Derivatives designated as hedging instruments:	Balance Sheet Location	Fair Value			Balance Sheet Location	Fair Value
Swap Agreements	Other assets	$	7,317		Other assets	$	13,630
Swap Agreements	Other liabilities	$	(1,818	)	Other liabilities	$	(3,684	)

Effect of Derivative Instruments

The tables below present the effect of the Company’s derivative financial instruments on the condensed consolidated statements of operations for the periods presented. No tax effect has been presented as the derivative instruments are held by the Company:


	Classification of Income (Expense)		For the Three Months Ended September 30,						For the Nine Months Ended September 30,
Type	Classification of Income (Expense)		2014			2013			2014			2013
Swap Agreements		Interest expense	$	(2,172	)	$	(2,307	)	$	(6,782	)	$	(6,589	)


	Gain (loss) recognized in OCI			Gain (loss) reclassified from OCI
Type	September 30, 2014		Location of amounts reclassified from OCI into income	For the Nine Months Ended September 30, 2014
Swap Agreements	$	(11,099)	Interest expense	$	(6,782)


	Gain (loss) recognized in OCI			Gain (loss) reclassified from OCI
Type	September 30, 2013		Location of amounts reclassified from OCI into income	For the Nine Months Ended September 30, 2013
Swap Agreements	$	10,837	Interest expense	$	(6,589)

Credit-risk-related Contingent Features

The Company has agreements with some of its derivative counterparties that contain provisions pursuant to which the Company could be declared in default of its derivative obligations if the Company defaults on any of its indebtedness, including default where repayment of the indebtedness has not been accelerated by the lender.

The Company also has an agreement with some of its derivative counterparties that incorporates the loan covenant provisions of the Company’s indebtedness with a lender affiliate of the derivative counterparty. Failure to comply with the loan covenant provisions would result in the Company being in default on any derivative instrument obligations covered by the agreement.

As of September 30, 2014, the fair value of derivatives in a net liability position, which includes accrued interest but excludes any adjustment for nonperformance risk related to these agreements, was $1,818. As of September 30, 2014, the Company had not posted any collateral related to these agreements. If the Company had breached any of these provisions as of September 30, 2014, it could have been required to settle its obligations under the agreements at their termination value of $2,003.

- Definition

The entire disclosure for derivative instruments and hedging activities including, but not limited to, risk management strategies, non-hedging derivative instruments, assets, liabilities, revenue and expenses, and methodologies and assumptions used in determining the amounts.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 2: http://www.xbrl.org/2003/role/presentationRef
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Reference 3: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
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-Publisher FASB
-Name Accounting Standards Codification
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-Publisher FASB
-Name Accounting Standards Codification
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Reference 13: http://www.xbrl.org/2003/role/presentationRef
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Reference 14: http://www.xbrl.org/2003/role/presentationRef
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+ Details

Exchangeable Senior Notes

9 Months Ended

Sep. 30, 2014

Text Block [Abstract]

Exchangeable Senior Notes

9.	EXCHANGEABLE SENIOR NOTES

On June 21, 2013, the Operating Partnership issued $250,000 of its 2.375% Exchangeable Senior Notes due 2033 at a 1.5% discount, or $3,750. Costs incurred to issue the Notes were approximately $1,672. These costs are being amortized as an adjustment to interest expense over five years, which represents the estimated term based on the first available redemption date, and are included in other assets in the condensed consolidated balance sheets. The Notes are general unsecured senior obligations of the Operating Partnership and are fully guaranteed by the Company. Interest is payable on January 1 and July 1 of each year beginning January 1, 2014, until the maturity date of July 1, 2033. The Notes bear interest at 2.375% per annum and contain an exchange settlement feature, which provides that the Notes may, under certain circumstances, be exchangeable for cash (for the principal amount of the Notes) and, with respect to any excess exchange value, for cash, shares of the Company’s common stock, or a combination of cash and shares of the Company’s common stock, at the Company’s option. The exchange rate of the Notes as of September 30, 2014 was approximately 17.98 shares of the Company’s common stock per $1,000 principal amount of the Notes.

The Operating Partnership may redeem the Notes at any time to preserve the Company’s status as a REIT. In addition, on or after July 5, 2018, the Operating Partnership may redeem the Notes for cash, in whole or in part, at 100% of the principal amount plus accrued and unpaid interest, upon at least 30 days but not more than 60 days prior written notice to the holders of the Notes. The holders of the Notes have the right to require the Operating Partnership to repurchase the Notes for cash, in whole or in part, on July 1 of the years 2018, 2023 and 2028, and upon the occurrence of certain designated events, in each case for a repurchase price equal to 100% of the principal amount of the Notes plus accrued and unpaid interest. Certain events are considered “Events of Default,” as defined in the indenture governing the Notes, which may result in the accelerated maturity of the Notes.

GAAP requires entities with convertible debt instruments that may be settled entirely or partially in cash upon conversion to separately account for the liability and equity components of the instrument in a manner that reflects the issuer’s economic interest cost. The Company therefore accounts for the liability and equity components of the Notes separately. The equity component is included in paid-in capital in stockholders’ equity in the condensed consolidated balance sheets, and the value of the equity component is treated as original issue discount for purposes of accounting for the debt component. The discount is being amortized as interest expense over the remaining period of the debt through its first redemption date, July 1, 2018. The effective interest rate on the liability component is 4.0%.

Information about the carrying amount of the equity component, the principal amount of the liability component, its unamortized discount and its net carrying amount for the Notes was as follows for the periods indicated:


	September 30, 2014			December 31, 2013
Carrying amount of equity component	$	14,496		$	14,496


Principal amount of liability component	$	250,000		$	250,000
Unamortized discount—equity component		(11,127	)		(13,131	)
Unamortized cash discount		(2,793	)		(3,356	)

Net carrying amount of liability component	$	236,080		$	233,513

The amount of interest cost recognized relating to the contractual interest rate and the amortization of the discount on the liability component of the Notes were as follows for the periods indicated:


	For the Three Months Ended September 30,				For the Nine Months Ended September 30,
	2014		2013		2014		2013
Contractual interest	$	1,484	$	1,484	$	4,452	$	1,632
Amortization of discount		679		834		2,004		947

Total interest expense recognized	$	2,163	$	2,318	$	6,456	$	2,579

Noncontrolling Interests

9 Months Ended

Sep. 30, 2014

Noncontrolling Interests

12.

OTHER NONCONTROLLING INTERESTS

Other noncontrolling interests represent the ownership interests of various third parties in two consolidated joint ventures as of September 30, 2014. One of these consolidated joint ventures owns one property which was under construction at September 30, 2014. The second consolidated joint venture owns 19 operating properties. The ownership interests of the third-party owners range from 1.0% to 3.3%. Other noncontrolling interests are included in the stockholders’ equity section of the Company’s condensed consolidated balance sheets. The income or losses attributable to these third-party owners based on their ownership percentages are reflected in net income allocated to Operating Partnership and other noncontrolling interests in the condensed consolidated statements of operations.

In May 2013, the Company purchased one of its joint venture partner’s 27.7% capital interest and 35.0% profit interest in a previously unconsolidated joint venture for $950. The partner’s interest was reported in other noncontrolling interests prior to the purchase. As a result of the acquisition, the property became wholly-owned by the Company. Since the Company retained its controlling financial interest in the subsidiary, this transaction was accounted for as an equity transaction. The carrying amount of the noncontrolling interest was reduced to zero to reflect the purchase, and the difference between the price paid by the Company and the carrying value of the noncontrolling interest was recorded as an adjustment to equity attributable to the parent.

In February 2013, the Company purchased one of its joint venture partner’s 1.7% capital interest and 17.0% profit interest in one of its consolidated joint ventures for $200. As a result, the Company’s capital interest percentage in this joint venture increased from 95.0% to 96.7%. Since the Company retained its controlling financial interest in the subsidiary, this transaction was accounted for as an equity transaction. The carrying amount of the noncontrolling interest was reduced to reflect the purchase and the difference between the price paid by the Company and the adjustment to the carrying value of the noncontrolling interest was recorded as an adjustment to equity attributable to the parent.

Preferred Operating Partnership Units [Member]

Noncontrolling Interests

10.

NONCONTROLLING INTEREST REPRESENTED BY PREFERRED OPERATING PARTNERSHIP UNITS

Classification of Noncontrolling Interests

GAAP requires a company to present ownership interests in subsidiaries held by parties other than the company in the consolidated financial statements within the equity section, but separate from the company’s equity. It also requires the amount of consolidated net income attributable to the parent and to the noncontrolling interest to be clearly identified and presented on the face of the consolidated statement of operations and requires changes in ownership interest to be accounted for similarly as equity transactions. If noncontrolling interests are determined to be redeemable, they are to be carried at their redemption value as of the balance sheet date and reported as temporary equity.

The Company has evaluated the terms of the Operating Partnership’s preferred units and classifies the noncontrolling interest represented by such preferred units as stockholders’ equity in the accompanying condensed consolidated balance sheets. The Company will periodically evaluate individual noncontrolling interests for the ability to continue to recognize the noncontrolling interest as permanent equity in the condensed consolidated balance sheets. Any noncontrolling interests that fail to qualify as permanent equity will be reclassified as temporary equity and adjusted to the greater of (1) the carrying amount and (2) the redemption value as of the end of the period in which the determination is made.

Series A Participating Redeemable Preferred Units

On June 15, 2007, the Operating Partnership entered into a Contribution Agreement with various limited partnerships affiliated with AAAAA Rent-A-Space to acquire ten self-storage facilities in exchange for 989,980 Series A Units of the Operating Partnership. The self-storage facilities are located in California and Hawaii.

On June 25, 2007, the Operating Partnership loaned the holders of the Series A Units $100,000. The note receivable bears interest at 4.85% and is due September 1, 2020. The loan is secured by the borrower’s Series A Units. The holders of the Series A Units can redeem up to 114,500 Series A Units prior to the maturity date of the loan. If any redemption in excess of 114,500 Series A Units occurs prior to the maturity date, the holder of the Series A Units is required to repay the loan as of the date of that redemption. The Series A Units are shown on the condensed consolidated balance sheets net of the $100,000 loan because the borrower under the loan receivable is also the holder of the Series A Units. Subsequent to the end of the quarter, the holder of the Series A Units redeemed 114,500 units for $4,794 of cash and 280,331 shares of the Company’s common stock for a total value of $19,175.

The partnership agreement of the Operating Partnership (as amended, the “Partnership Agreement”) provides for the designation and issuance of the Series A Units. The Series A Units will have priority over all other partnership interests of the Operating Partnership with respect to distributions and liquidation.

Under the Partnership Agreement, Series A Units in the amount of $115,000 bear a fixed priority return of 5% and have a fixed liquidation value of $115,000. The remaining balance participates in distributions with, and has a liquidation value equal to, that of the OP Units. The Series A Units are redeemable at the option of the holder, which redemption obligation may be satisfied, at the Company’s option, in cash or shares of its common stock.

Series B Redeemable Preferred Units

On April 3, 2014, the Operating Partnership completed the purchase of a self-storage facility located in Georgia. This property was acquired in exchange for $15,158 of cash and 333,360 Series B Units valued at $8,334.

The Partnership Agreement provides for the designation and issuance of the Series B Units. The Series B Units rank junior to the Series A Units, on parity with the Series C Units, and senior to all other partnership interests of the Operating Partnership with respect to distributions and liquidation.

The outstanding Series B Units have a liquidation value of $25.00 per unit for a fixed liquidation value of $41,902. Holders of the Series B Units receive distributions at an annual rate of 6%. These distributions are cumulative. The Series B Units will become redeemable at the option of the holder on the first anniversary of the date of issuance, which redemption obligation may be satisfied at the Company’s option in cash or shares of its common stock.

Series C Convertible Redeemable Preferred Units

On November 19, 2013, the Company entered into Contribution Agreements with various entities affiliated with Grupe Properties Co. Inc. (“Grupe”), under which the Company agreed to acquire twelve self-storage facilities, all of which are located in California. The Company completed the purchase of these self-storage facilities between December 2013 and May 2014. The Company previously held 35% interests in five of these properties and a 40% interest in one property through six separate joint ventures with Grupe. These properties were acquired in exchange for a total of approximately $45,722 of cash, the assumption of $37,532 in existing debt, and the issuance of 704,016 Series C Units valued at $30,960.

The Partnership Agreement provides for the designation and issuance of the Series C Units. The Series C Units rank junior to the Series A Units, on parity with the Series B Units, and senior to all other partnership interests of the Operating Partnership with respect to distributions and liquidation.

The outstanding Series C Units have a liquidation value of $42.10 per unit for a fixed liquidation value of $29,639. From issuance to the fifth anniversary of issuance, each Series C Unit holder will receive quarterly distributions equal to the quarterly distribution per OP Unit plus $0.18. Beginning on the fifth anniversary of issuance, each Series C Unit holder will receive a fixed quarterly distribution equal to the aggregate quarterly distribution payable in respect of such Series C Unit during the four quarters immediately preceding the fifth anniversary of issuance, divided by four. These distributions are cumulative. The Series C Units will become redeemable at the option of the holder one year from the date of issuance, which redemption obligation may be satisfied at the Company’s option in cash or shares of its common stock. The Series C Units will also become convertible into OP Units at the option of the holder one year from the date of issuance, at a rate of 0.9145 OP Units per Series C Unit converted. This conversion option expires upon the fifth anniversary of the date of issuance.

Common Operating Partnership [Member]

Noncontrolling Interests

11.

NONCONTROLLING INTEREST IN OPERATING PARTNERSHIP

The Company’s interest in its properties is held through the Operating Partnership. ESS Holding Business Trust I, a wholly-owned subsidiary of the Company, is the sole general partner of the Operating Partnership. ESS Holding Business Trust II, also a wholly-owned subsidiary of the Company, is a limited partner of the Operating Partnership. Between its general partner and limited partner interests, the Company held a 93.8% ownership interest in the Operating Partnership as of September 30, 2014. The remaining ownership interests in the Operating Partnership (including Preferred Operating Partnership units) of 6.2% are held by certain former owners of assets acquired by the Operating Partnership.

The noncontrolling interest in the Operating Partnership represents OP Units that are not owned by the Company. In conjunction with the formation of the Company, and as a result of subsequent acquisitions, certain persons and entities contributing interests in properties to the Operating Partnership received limited partnership interests in the form of OP Units. Limited partners who received OP Units in the formation transactions or in exchange for contributions for interests in properties have the right to require the Operating Partnership to redeem part or all of their OP Units for cash based upon the fair market value of an equivalent number of shares of the Company’s common stock (based on the ten-day average trading price) at the time of the redemption. Alternatively, the Company may, in its sole discretion, elect to acquire those OP Units in exchange for shares of its common stock on a one-for-one basis, subject to anti-dilution adjustments provided in the Partnership Agreement. The ten-day average closing stock price at September 30, 2014 was $51.31 and there were 4,334,118 OP Units outstanding. Assuming that all of the OP Unit holders exercised their right to redeem all of their OP Units on September 30, 2014 and the Company elected to pay the OP Unit holders cash, the Company would have paid $222,384 in cash consideration to redeem the units.

GAAP requires a company to present ownership interests in subsidiaries held by parties other than the company in the consolidated financial statements within the equity section, but separate from the company’s equity. It also requires the amount of consolidated net income attributable to the parent and to the noncontrolling interest to be clearly identified and presented on the face of the consolidated statement of operations, and requires changes in ownership interest to be accounted for similarly as equity transactions. If noncontrolling interests are determined to be redeemable, they are to be carried at their redemption value as of the balance sheet date and reported as temporary equity.

The Company has evaluated the terms of the OP Units and classifies the noncontrolling interest represented by the OP Units as stockholders’ equity in the accompanying condensed consolidated balance sheets. The Company will periodically evaluate individual noncontrolling interests for the ability to continue to recognize the noncontrolling amount as permanent equity in the condensed consolidated balance sheets. Any noncontrolling interests that fail to qualify as permanent equity will be reclassified as temporary equity and adjusted to the greater of (1) the carrying amount and (2) the redemption value as of the end of the period in which the determination is made.

Equity in Earnings of Unconsolidated Real Estate Ventures - Purchase of Joint Venture Partners' Interests

9 Months Ended

Sep. 30, 2014

Equity Method Investments and Joint Ventures [Abstract]

Equity in Earnings of Unconsolidated Real Estate Ventures - Purchase of Joint Venture Partners' Interests

13.

EQUITY IN EARNINGS OF UNCONSOLIDATED REAL ESTATE VENTURES—GAIN ON PURCHASE OF JOINT VENTURE PARTNERS’ INTERESTS

Between December 2013 and May 2014, as part of the Grupe acquisition, the Company acquired its joint venture partners’ 60% to 65% equity interests in six self-storage properties located in California. The Company previously held the remaining 35% to 40% interests in these properties through six separate joint ventures with Grupe. Prior to the acquisition, the Company accounted for its interests in these joint ventures as equity-method investments. The Company recognized a non-cash gain of $3,438 during the nine months ending September 30, 2014 as a result of re-measuring the fair value of its equity interest in one of these joint ventures held before the acquisition. During the three months ending September 30, 2014, the Company recorded a gain of $378 as a result of the final cash distributions received from the other five joint ventures associated with the acquisitions that were completed during 2013.

On February 13, 2013, the Company acquired its joint venture partner’s 48% equity interest in Extra Space of Eastern Avenue LLC (“Eastern Avenue”), which owned one self-storage property located in Maryland, for approximately $5,979. Prior to the acquisition, the remaining 52% interest was owned by the Company, which accounted for its investment in Eastern Avenue using the equity method. The Company recorded a non-cash gain of $2,215 related to this transaction, which represents the increase in fair value of the Company’s interest in Eastern Avenue from its formation to the acquisition date.

On February 13, 2013, the Company acquired its joint venture partner’s 61% equity interest in Extra Space of Montrose Avenue LLC (“Montrose”), which owned one self-storage property located in Illinois, for approximately $6,878. Prior to the acquisition, the remaining 39% interest was owned by the Company, which accounted for its investment in Montrose using the equity method. The Company recorded a non-cash gain of $341 related to this transaction, which represents the increase in fair value of the Company’s interest in the joint venture from its formation to the acquisition date.

Segment Information

9 Months Ended

Sep. 30, 2014

Segment Reporting [Abstract]

Segment Information

14.

SEGMENT INFORMATION

The Company operates in three distinct segments: (1) rental operations; (2) tenant reinsurance; and (3) property management, acquisition and development. Management fees collected for wholly-owned properties are eliminated in consolidation. Financial information for the Company’s business segments is presented below:


	September 30, 2014		December 31, 2013
Balance Sheet
Investment in unconsolidated real estate ventures
Rental operations	$	86,232	$	88,125

Total assets
Rental operations	$	3,960,442	$	3,641,746
Tenant reinsurance		32,520		34,393
Property management, acquisition and development		232,933		301,001

	$	4,225,895	$	3,977,140


	For the Three Months Ended September 30,						For the Nine Months Ended September 30,
	2014			2013			2014			2013
Statement of Operations
Total revenues
Rental operations	$	144,669		$	113,881		$	415,448		$	324,144
Tenant reinsurance		15,385			12,294			43,356			34,625
Property management, acquisition and development		7,314			6,936			20,984			19,910

		167,368			133,111			479,788			378,679

Operating expenses, including depreciation and amortization
Rental operations		70,520			56,428			209,082			167,300
Tenant reinsurance		2,930			2,873			8,133			6,985
Property management, acquisition and development		16,425			17,746			54,021			48,226

		89,875			77,047			271,236			222,511

Income (loss) from operations
Rental operations		74,149			57,453			206,366			156,844
Tenant reinsurance		12,455			9,421			35,223			27,640
Property management, acquisition and development		(9,111	)		(10,810	)		(33,037	)		(28,316	)

		77,493			56,064			208,552			156,168

Gain (loss) on sale of real estate and earnout from prior acquisitions
Rental operations		—			—			—			800
Property management, acquisition and development		(2,500	)		—			(10,285	)		—

		(2,500	)		—			(10,285	)		800
Loss on extinguishment of debt related to portfolio acquisition
Property management, acquisition and development		—			(9,153	)		—			(9,153	)

Interest expense
Rental operations		(20,416	)		(15,608	)		(60,074	)		(50,657	)
Property management, acquisition and development		(265	)		(656	)		(863	)		(1,335	)

		(20,681	)		(16,264	)		(60,937	)		(51,992	)

Non-cash interest expense related to the amortization of discount on equity component of exchangeable senior notes
Property management, acquisition and development		(679	)		(834	)		(2,004	)		(947	)

Interest income
Tenant reinsurance		5			5			13			13
Property management, acquisition and development		181			197			1,154			506

		186			202			1,167			519

Interest income on note receivable from Preferred Operating Partnership unit holder
Property management, acquisition and development		1,213			1,213			3,638			3,638

Equity in earnings of unconsolidated real estate ventures
Rental operations		2,777			3,405			7,800			8,942

Equity in earnings of unconsolidated real estate ventures—gain on purchase of joint venture partners’ interests
Rental operations		378			—			3,816			2,556

Income tax (expense) benefit
Rental operations		(222	)		334			(914	)		(134	)
Tenant reinsurance		2,011			(3,300	)		(5,660	)		(12,545	)
Property management, acquisition and development		(783	)		685			1,237			5,532

		1,006			(2,281	)		(5,337	)		(7,147	)

Net income (loss)
Rental operations		56,666			45,584			156,994			118,351
Tenant reinsurance		14,471			6,126			29,576			15,108
Property management, acquisition and development		(11,944	)		(19,358	)		(40,160	)		(30,075	)

	$	59,193		$	32,352		$	146,410		$	103,384

Depreciation and amortization expense
Rental operations	$	27,226		$	22,052		$	80,012		$	65,025
Property management, acquisition and development		2,023			1,376			5,883			4,213

	$	29,249		$	23,428		$	85,895		$	69,238

Statement of Cash Flows
Acquisition of real estate assets
Property management, acquisition and development	$	(31,315	)	$	(23,245	)	$	(328,235	)	$	(82,949	)

Development and redevelopment of real estate assets
Property management, acquisition and development	$	(5,330	)	$	(1,609	)	$	(11,288	)	$	(3,941	)

- Definition

The entire disclosure for reporting segments including data and tables. Reportable segments include those that meet any of the following quantitative thresholds a) it's reported revenue, including sales to external customers and intersegment sales or transfers is 10 percent or more of the combined revenue, internal and external, of all operating segments b) the absolute amount of its reported profit or loss is 10 percent or more of the greater, in absolute amount of 1) the combined reported profit of all operating segments that did not report a loss or 2) the combined reported loss of all operating segments that did report a loss c) its assets are 10 percent or more of the combined assets of all operating segments.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 34
-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e8981-108599

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 41
-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e9038-108599

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 33
-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e8971-108599

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 12
-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e8595-108599

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e8380-108599

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 32
-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e8933-108599

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 26
-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e8844-108599

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 35
-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e8984-108599

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 40
-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e9031-108599

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 42
-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e9054-108599

Reference 11: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e8538-108599

Reference 12: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 29
-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e8864-108599

Reference 13: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 31
-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e8924-108599

Reference 14: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
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-Section 50
-Paragraph 30
-URI http://asc.fasb.org/extlink&oid=6534315&loc=d3e8906-108599

+ Details

Commitments and Contingencies

9 Months Ended

Sep. 30, 2014

Commitments and Contingencies Disclosure [Abstract]

Commitments and Contingencies

15.

COMMITMENTS AND CONTINGENCIES

As of September 30, 2014, the Company is involved in various legal proceedings and is subject to various claims and complaints arising in the ordinary course of business. In the opinion of management, such litigation, claims and complaints are not expected to have a material adverse effect on the Company’s financial condition or results of operations.

Subsequent Events

9 Months Ended

Sep. 30, 2014

Subsequent Events [Abstract]

Subsequent Events

16.

SUBSEQUENT EVENTS

On October 22, 2014, the Company purchased a self-storage property located in Georgia for $11,000.

On October 24, 2014, the Company purchased a self-storage property located in Colorado for $6,250.

Basis of Presentation (Policies)	9 Months Ended
Basis of Presentation (Policies)	Sep. 30, 2014
Accounting Policies [Abstract]
Reclassifications	Reclassifications Certain amounts in the Company’s 2013 consolidated financial statements and supporting note disclosures have been reclassified to conform to the current period presentation. Such reclassifications did not impact previously reported net income or accumulated deficit.
Recently Issued Accounting Standards	Recently Issued Accounting Standards In May 2014, the Financial Accounting Standards Board issued Accounting Standards Update (“ASU”) 2014-09, “Revenue from Contracts with Customers” (“ASU 2014-09”). ASU 2014-09 amends the guidance for revenue recognition to replace numerous, industry-specific requirements and converges areas under this topic with those of the International Financial Reporting Standards. ASU 2014-09 outlines a five-step process for customer contract revenue recognition that focuses on transfer of control, as opposed to transfer of risk and rewards. The amendment also requires enhanced disclosures regarding the nature, amount, timing and uncertainty of revenues and cash flows from contracts with customers. ASU 2014-09 is effective for reporting periods beginning after December 15, 2016, and early adoption is prohibited. Entities can transition to the standard either retrospectively or as a cumulative-effect adjustment as of the date of adoption. Management is currently assessing the impact of the adoption of ASU 2014-09 on the Company’s condensed consolidated financial statements.

Fair Value Disclosures (Tables)

9 Months Ended

Sep. 30, 2014

Fair Value Disclosures [Abstract]

Schedule of Assets and Liabilities Measured at Fair Value on a Recurring Basis


				Fair Value Measurements at Reporting Date Using
Description	September 30, 2014			Quoted Prices in Active Markets for Identical Assets (Level 1)		Significant Other Observable Inputs (Level 2)			Significant Unobservable Inputs (Level 3)
Other assets—Cash Flow Hedge Swap Agreements	$	7,317		$	—	$	7,317		$	—
Other liabilities—Cash Flow Hedge Swap Agreements	$	(1,818	)	$	—	$	(1,818	)	$	—

Schedule of Fair Value of Financial Instruments

The fair values of the Company’s fixed-rate assets and liabilities were as follows for the periods indicated:


	September 30, 2014				December 31, 2013
	Fair Value		Carrying Value		Fair Value		Carrying Value
Note receivable from Preferred Operating Partnership unit holders	$	103,667	$	100,000	$	103,491	$	100,000
Fixed rate notes payable and notes payable to trusts	$	1,318,359	$	1,294,510	$	1,365,290	$	1,368,885
Exchangeable senior notes	$	259,843	$	250,000	$	251,103	$	250,000

Earnings Per Common Share (Tables)

9 Months Ended

Sep. 30, 2014

Earnings Per Share [Abstract]

Schedule of Computation of Earnings Per Common Share

The computation of earnings per common share was as follows for the periods presented:


	For the Three Months Ended September 30,						For the Nine Months Ended September 30,
	2014			2013			2014			2013
Net income attributable to common stockholders	$	54,228		$	29,245		$	133,233		$	95,136
Earnings and dividends allocated to participating securities		(125	)		(143	)		(366	)		(390	)

Earnings for basic computations		54,103			29,102			132,867			94,746

Earnings and dividends allocated to participating securities		125			—			366			—
Income allocated to noncontrolling interest—Preferred Operating Partnership (Series A Units) and Operating Partnership		3,875			2,757			10,318			7,875
Fixed component of income allocated to noncontrolling interest—Preferred Operating Partnership (Series A Units)		(1,438	)		(1,438	)		(4,313	)		(4,313	)

Net income for diluted computations	$	56,665		$	30,421		$	139,238		$	98,308

Weighted average common shares outstanding:
Average number of common shares outstanding—basic		115,726,911			110,827,793			115,606,845			110,624,757
Series A Units		989,980			—			989,980			—
Common OP Units		4,334,118			4,346,618			4,334,118			4,346,618
Unvested restricted stock awards included for treasury stock method		294,616			—			321,346			—
Dilutive stock options		271,929			302,734			299,600			351,684

Average number of common shares outstanding—diluted		121,617,554			115,477,145			121,551,889			115,323,059

Earnings per common share
Basic	$	0.47		$	0.26		$	1.15		$	0.86
Diluted	$	0.47		$	0.26		$	1.15		$	0.85

Property Acquisitions and Dispositions (Tables)

9 Months Ended

Sep. 30, 2014

Business Combinations [Abstract]

Schedule of Operating Properties Acquired


					Consideration Paid																	Acquisition Date Fair Value
Property Location	Number of Properties		Date of Acquisition		Total		Cash Paid		Loan Assumed		Non-cash gain		Previous equity interest		Net Liabilities/ (Assets) Assumed			Value of OP Units Issued		Number of OP Units Issued		Land		Building		Intangible		Closing costs - expensed		Notes
Virginia		17		1/7/2014	$	200,588	$	200,525	$	—	$	—	$	—	$	63		$	—		—	$	53,878	$	142,840	$	2,973	$	897
Texas		1		2/5/2014		14,191		14,152		—		—		—		39			—		—		1,767		12,368		38		18
California		1		3/4/2014		7,000		6,974		—		—		—		26			—		—		2,150		4,734		113		3		(1)
Connecticut		1		3/17/2014		15,138		15,169		—		—		—		(31	)		—		—		1,072		14,028		—		38
Alabama		1		3/20/2014		13,813		13,752		—		—		—		61			—		—		2,381		11,224		200		8
Georgia		1		4/3/2014		23,649		15,158		—		—		—		157			8,334		333,360		2,961		19,819		242		627
Florida		1		4/15/2014		10,186		10,077		—		—		—		109			—		—		1,640		8,358		149		39
California		3		4/25/2014		35,275		2,726		19,111		3,438		129		(580	)		10,451		226,285		6,853		27,666		579		177		(2)
Washington		1		4/30/2014		4,388		4,388		—		—		—		—			—		—		437		3,808		102		41
California		1		5/28/2014		17,614		294		14,079		—		—		(92	)		3,333		69,735		4,707		12,604		265		38
North Carolina		1		6/18/2014		7,310		7,307		—		—		—		3			—		—		2,940		4,265		93		12
Georgia		1		8/6/2014		11,337		11,290		—		—		—		47			—		—		1,132		10,080		111		14
Texas		1		8/8/2014		11,246		6,134		5,157		—		—		(45	)		—		—		1,047		9,969		181		49
Florida		1		9/3/2014		4,259		4,225		—		—		—		34			—		—		529		3,604		81		45

2014 Totals		32			$	375,994	$	312,171	$	38,347	$	3,438	$	129	$	(209	)	$	22,118		629,380	$	83,494	$	285,367	$	5,127	$	2,006

(1)

(2)

Variable Interests (Tables)

9 Months Ended

Sep. 30, 2014

Equity Method Investments and Joint Ventures [Abstract]

Schedule of the Comparison of the Liability Balance and the Maximum Exposure to Loss Related to the Company's each VIE

The following table compares the liability balance and the maximum exposure to loss related to the Company’s VIE JV as of September 30, 2014:


	Liability Balance		Investment Balance			Amounts Payable to the Company		Maximum Exposure to Loss		Difference
Extra Space of Sacramento One LLC	$	—	$	(1,232	)	$	10,726	$	9,494	$	(9,494	)

Schedule of the Liabilities and the Maximum Exposure to Loss Related to the Trusts


	Notes payable to Trusts		Investment Balance		Maximum exposure to loss		Difference
Trust	$	36,083	$	1,083	$	35,000	$	—
Trust II		42,269		1,269		41,000		—
Trust III		41,238		1,238		40,000		—

	$	119,590	$	3,590	$	116,000	$	—

Derivatives (Tables)

9 Months Ended

Sep. 30, 2014

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Schedule Summarizing the Terms of Entity's Derivative Financial Instruments

The following table summarizes the terms of the Company’s 20 derivative financial instruments as of September 30, 2014:


Hedge Product	Current Notional Amounts	Strike	Effective Dates	Maturity Dates
Swap Agreements	$4,687 - $95,004	2.79% - 6.12%	11/2/2009 - 1/1/2014	11/1/2014 - 4/1/2021

Schedule of Balance Sheet Classification and Fair Value of the Entity's Derivative Financial Instruments

The table below presents the fair value of the Company’s derivative financial instruments as well as their classification on the condensed consolidated balance sheets:


	Asset (Liability) Derivatives
	September 30, 2014				December 31, 2013
Derivatives designated as hedging instruments:	Balance Sheet Location	Fair Value			Balance Sheet Location	Fair Value
Swap Agreements	Other assets	$	7,317		Other assets	$	13,630
Swap Agreements	Other liabilities	$	(1,818	)	Other liabilities	$	(3,684	)

Interest Payments Recognized as an Increase or Decrease in Interest Expense


	Classification of Income (Expense)		For the Three Months Ended September 30,						For the Nine Months Ended September 30,
Type	Classification of Income (Expense)		2014			2013			2014			2013
Swap Agreements		Interest expense	$	(2,172	)	$	(2,307	)	$	(6,782	)	$	(6,589	)

Schedule of Information Relating to the Gain (Loss) Recognized on the Swap Agreements

Gain (loss) recognized in OCI			Gain (loss) reclassified from OCI
Type	September 30, 2014		Location of amounts reclassified from OCI into income	For the Nine Months Ended September 30, 2014
Swap Agreements	$	(11,099)	Interest expense	$	(6,782)


	Gain (loss) recognized in OCI			Gain (loss) reclassified from OCI
Type	September 30, 2013		Location of amounts reclassified from OCI into income	For the Nine Months Ended September 30, 2013
Swap Agreements	$	10,837	Interest expense	$	(6,589)

- Definition

Tabular disclosure of pertinent information about a derivative or group of derivatives on a disaggregated basis, such as for individual instruments, or small groups of similar instruments. May include a combination of the type of instrument, risks being hedged, notional amount, hedge designation, related hedged item, inception date, maturity date, or other relevant item.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=35706170&loc=d3e41641-113959

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4B
-URI http://asc.fasb.org/extlink&oid=35706170&loc=SL5624163-113959

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=35706170&loc=d3e41678-113959

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=35706170&loc=d3e41638-113959

Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1B
-URI http://asc.fasb.org/extlink&oid=35706170&loc=SL5580258-113959

Reference 6: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1A
-URI http://asc.fasb.org/extlink&oid=35706170&loc=SL5579245-113959

Reference 7: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4C
-URI http://asc.fasb.org/extlink&oid=35706170&loc=SL5624171-113959

Reference 8: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 25
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6886632&loc=d3e76258-113986

Reference 9: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=35706170&loc=SL5579240-113959

Reference 10: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=35706170&loc=d3e41620-113959

Reference 11: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(n)(2))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

+ Details

Exchangeable Senior Notes (Tables)

9 Months Ended

Sep. 30, 2014

Text Block [Abstract]

Schedule of Information about the Carrying Amount of the Equity Component, the Principal Amount of the Liability Component, Unamortized Discount and Net Carrying Amount for the Notes


	September 30, 2014			December 31, 2013
Carrying amount of equity component	$	14,496		$	14,496


Principal amount of liability component	$	250,000		$	250,000
Unamortized discount—equity component		(11,127	)		(13,131	)
Unamortized cash discount		(2,793	)		(3,356	)

Net carrying amount of liability component	$	236,080		$	233,513

Summary of Amount of Interest Cost Recognized Relating to the Contractual Interest Rate and the Amortization of the Discount on the Liability Component of the Notes


	For the Three Months Ended September 30,				For the Nine Months Ended September 30,
	2014		2013		2014		2013
Contractual interest	$	1,484	$	1,484	$	4,452	$	1,632
Amortization of discount		679		834		2,004		947

Total interest expense recognized	$	2,163	$	2,318	$	6,456	$	2,579

Segment Information (Tables)

9 Months Ended

Sep. 30, 2014

Segment Reporting [Abstract]

Schedule of Financial Information of Business Segments

Financial information for the Company’s business segments is presented below:


	September 30, 2014		December 31, 2013
Balance Sheet
Investment in unconsolidated real estate ventures
Rental operations	$	86,232	$	88,125

Total assets
Rental operations	$	3,960,442	$	3,641,746
Tenant reinsurance		32,520		34,393
Property management, acquisition and development		232,933		301,001

	$	4,225,895	$	3,977,140


	For the Three Months Ended September 30,						For the Nine Months Ended September 30,
	2014			2013			2014			2013
Statement of Operations
Total revenues
Rental operations	$	144,669		$	113,881		$	415,448		$	324,144
Tenant reinsurance		15,385			12,294			43,356			34,625
Property management, acquisition and development		7,314			6,936			20,984			19,910

		167,368			133,111			479,788			378,679

Operating expenses, including depreciation and amortization
Rental operations		70,520			56,428			209,082			167,300
Tenant reinsurance		2,930			2,873			8,133			6,985
Property management, acquisition and development		16,425			17,746			54,021			48,226

		89,875			77,047			271,236			222,511

Income (loss) from operations
Rental operations		74,149			57,453			206,366			156,844
Tenant reinsurance		12,455			9,421			35,223			27,640
Property management, acquisition and development		(9,111	)		(10,810	)		(33,037	)		(28,316	)

		77,493			56,064			208,552			156,168

Gain (loss) on sale of real estate and earnout from prior acquisitions
Rental operations		—			—			—			800
Property management, acquisition and development		(2,500	)		—			(10,285	)		—

		(2,500	)		—			(10,285	)		800
Loss on extinguishment of debt related to portfolio acquisition
Property management, acquisition and development		—			(9,153	)		—			(9,153	)

Interest expense
Rental operations		(20,416	)		(15,608	)		(60,074	)		(50,657	)
Property management, acquisition and development		(265	)		(656	)		(863	)		(1,335	)

		(20,681	)		(16,264	)		(60,937	)		(51,992	)

Non-cash interest expense related to the amortization of discount on equity component of exchangeable senior notes
Property management, acquisition and development		(679	)		(834	)		(2,004	)		(947	)

Interest income
Tenant reinsurance		5			5			13			13
Property management, acquisition and development		181			197			1,154			506

		186			202			1,167			519

Interest income on note receivable from Preferred Operating Partnership unit holder
Property management, acquisition and development		1,213			1,213			3,638			3,638

Equity in earnings of unconsolidated real estate ventures
Rental operations		2,777			3,405			7,800			8,942

Equity in earnings of unconsolidated real estate ventures—gain on purchase of joint venture partners’ interests
Rental operations		378			—			3,816			2,556

Income tax (expense) benefit
Rental operations		(222	)		334			(914	)		(134	)
Tenant reinsurance		2,011			(3,300	)		(5,660	)		(12,545	)
Property management, acquisition and development		(783	)		685			1,237			5,532

		1,006			(2,281	)		(5,337	)		(7,147	)

Net income (loss)
Rental operations		56,666			45,584			156,994			118,351
Tenant reinsurance		14,471			6,126			29,576			15,108
Property management, acquisition and development		(11,944	)		(19,358	)		(40,160	)		(30,075	)

	$	59,193		$	32,352		$	146,410		$	103,384

Depreciation and amortization expense
Rental operations	$	27,226		$	22,052		$	80,012		$	65,025
Property management, acquisition and development		2,023			1,376			5,883			4,213

	$	29,249		$	23,428		$	85,895		$	69,238

Statement of Cash Flows
Acquisition of real estate assets
Property management, acquisition and development	$	(31,315	)	$	(23,245	)	$	(328,235	)	$	(82,949	)

Development and redevelopment of real estate assets
Property management, acquisition and development	$	(5,330	)	$	(1,609	)	$	(11,288	)	$	(3,941	)

Organization - Additional Information (Detail)	9 Months Ended
Organization - Additional Information (Detail)	Sep. 30, 2014 Property State Segments
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of operating storage facilities in which the entity has equity interests (in properties)	810
Number of properties owned by franchisees and third parties	271
Number of operating properties owned and/or managed	1,081
Number of states in which operating storage facilities are located \| State	35
Number of reportable segments \| Segments	3
Maximum percentage of rental income accounted for by any single tenant	5.00%

Fair Value Disclosures - Schedule of Assets and Liabilities Measured at Fair Value on a Recurring Basis (Detail) - USD ($) $ in Thousands	Sep. 30, 2014	Dec. 31, 2013
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other assets-Cash Flow Hedge Swap Agreements	$ 7,317	$ 13,630
Other liabilities-Cash Flow Hedge Swap Agreements	(1,818)	$ (3,684)
Recurring Basis [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other assets-Cash Flow Hedge Swap Agreements	7,317
Other liabilities-Cash Flow Hedge Swap Agreements	(1,818)
Fair Value, Inputs, Level 1 [Member] \| Recurring Basis [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other assets-Cash Flow Hedge Swap Agreements	0
Other liabilities-Cash Flow Hedge Swap Agreements	0
Significant Other Observable Inputs (Level 2) [Member] \| Recurring Basis [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other assets-Cash Flow Hedge Swap Agreements	7,317
Other liabilities-Cash Flow Hedge Swap Agreements	(1,818)
Fair Value, Inputs, Level 3 [Member] \| Recurring Basis [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other assets-Cash Flow Hedge Swap Agreements	0
Other liabilities-Cash Flow Hedge Swap Agreements	$ 0

Fair Value Disclosures - Additional Information (Detail) $ in Thousands	9 Months Ended
	Sep. 30, 2014 USD ($)
Fair Value Disclosures [Abstract]
Transfers of assets and liabilities between Level 1 and Level 2	$ 0

Fair Value Disclosures - Schedule of Fair Value of Financial Instruments (Detail) - USD ($) $ in Thousands	Sep. 30, 2014	Dec. 31, 2013
Fair Value of Financial Instruments [Line Items]
Note receivable from Preferred Operating Partnership unit holders	$ 100,000	$ 100,000
Exchangeable senior notes	250,000	250,000
Fair Value [Member]
Fair Value of Financial Instruments [Line Items]
Note receivable from Preferred Operating Partnership unit holders	100,000	100,000
Fixed rate notes payable and notes payable to trusts	294,510	1,368,885
Exchangeable senior notes	250,000	250,000
Carrying Value [Member]
Fair Value of Financial Instruments [Line Items]
Note receivable from Preferred Operating Partnership unit holders	103,667	103,491
Fixed rate notes payable and notes payable to trusts	318,359	1,365,290
Exchangeable senior notes	$ 259,843	$ 251,103

Earnings Per Common Share - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Jun. 21, 2013
Earnings Per Common Share [Line Items]
Anti-dilutive securities excluded from computation of earnings per common share	29,547	51,036	27,045	43,273
Shares related to the Notes included in the computation for diluted earnings per share	0		0
Average closing price of common stock	$ 50.29		$ 50.29
Anti-dilutive securities excluded from computation of earnings per common share	989,980		989,980
Series A Units [Member]
Earnings Per Common Share [Line Items]
Exchangeable preferred operating partnership units settled in cash, minimum	$ 115,000		$ 115,000
Series B Units [Member]
Earnings Per Common Share [Line Items]
Units outstanding	39,094		$ 39,094
Anti-dilutive securities excluded from computation of earnings per common share			777,364
Series C Units [Member]
Earnings Per Common Share [Line Items]
Units outstanding	24,080		$ 24,080
Anti-dilutive securities excluded from computation of earnings per common share			478,824
Operating Partnership [Member] \| 2.375% Exchangeable Senior Notes [Member]
Earnings Per Common Share [Line Items]
Principal amount of notes issued	$ 250,000		$ 250,000		$ 250,000
Interest rate (as a percent)	2.375%		2.375%		2.375%
Exchange price	$ 55.62		$ 55.62

Earnings Per Common Share - Schedule of Computation of Earnings Per Common Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Earnings Per Share [Abstract]
Net income attributable to common stockholders	$ 54,228	$ 29,245	$ 133,233	$ 95,136
Earnings and dividends allocated to participating securities	(125)	(143)	(366)	(390)
Earnings for basic computations	54,103	29,102	132,867	94,746
Earnings and dividends allocated to participating securities	125		366
Income allocated to noncontrolling interest-Preferred Operating Partnership (Series A Units) and Operating Partnership	3,875	2,757	10,318	7,875
Fixed component of income allocated to noncontrolling interest-Preferred Operating Partnership (Series A Units)	(1,438)	(1,438)	(4,313)	(4,313)
Net income for diluted computations	$ 56,665	$ 30,421	$ 139,238	$ 98,308
Weighted average common shares outstanding:
Average number of common shares outstanding-basic	115,726,911	110,827,793	115,606,845	110,624,757
Series A Units	989,980		989,980
Common OP Units	4,334,118	4,346,618	4,334,118	4,346,618
Unvested restricted stock awards included for treasury stock method	294,616		321,346
Dilutive stock options	271,929	302,734	299,600	351,684
Average number of common shares outstanding-diluted	121,617,554	115,477,145	121,551,889	115,323,059
Earnings per common share
Basic	$ 0.47	$ 0.26	$ 1.15	$ 0.86
Diluted	$ 0.47	$ 0.26	$ 1.15	$ 0.85

Property Acquisitions and Dispositions - Schedule of Operating Properties Acquired (Detail) $ in Thousands	9 Months Ended
	Sep. 30, 2014 USD ($) Property shares	Sep. 30, 2013 USD ($)
Property Acquisitions [Line Items]
Number of Properties \| Property	32
Total Consideration Paid	$ 375,994
Cash Consideration Paid	312,171
Loan Assumed	38,347	$ 7,122
Non-cash gain	3,438	2,556
Previous equity interest	129
Net Liabilities (Assets) Assumed	(209)
Value of OP units issued	$ 22,118	$ 102,039
Number of OP Units Issued \| shares	629,380
Acquisition Date Fair Value, Land	$ 83,494
Acquisition Date Fair Value, Building	285,367
Acquisition Date Fair Value, Intangible	5,127
Closing costs - expensed	$ 2,006
Virginia, 17 Properties Acquired 1/7/2014 [Member]
Property Acquisitions [Line Items]
Number of Properties \| Property	17
Total Consideration Paid	$ 200,588
Cash Consideration Paid	200,525
Loan Assumed	0
Non-cash gain	0
Previous equity interest	0
Net Liabilities (Assets) Assumed	63
Value of OP units issued	$ 0
Number of OP Units Issued \| shares	0
Acquisition Date Fair Value, Land	$ 53,878
Acquisition Date Fair Value, Building	142,840
Acquisition Date Fair Value, Intangible	2,973
Closing costs - expensed	$ 897
Texas, 1 Property Acquired 2/5/2014 [Member]
Property Acquisitions [Line Items]
Number of Properties \| Property	1
Total Consideration Paid	$ 14,191
Cash Consideration Paid	14,152
Loan Assumed	0
Non-cash gain	0
Previous equity interest	0
Net Liabilities (Assets) Assumed	39
Value of OP units issued	$ 0
Number of OP Units Issued \| shares	0
Acquisition Date Fair Value, Land	$ 1,767
Acquisition Date Fair Value, Building	12,368
Acquisition Date Fair Value, Intangible	38
Closing costs - expensed	$ 18
California, 1 Property Acquired 3/4/2014 [Member]
Property Acquisitions [Line Items]
Number of Properties \| Property	1
Total Consideration Paid	$ 7,000
Cash Consideration Paid	6,974
Loan Assumed	0
Non-cash gain	0
Previous equity interest	0
Net Liabilities (Assets) Assumed	26
Value of OP units issued	$ 0
Number of OP Units Issued \| shares	0
Acquisition Date Fair Value, Land	$ 2,150
Acquisition Date Fair Value, Building	4,734
Acquisition Date Fair Value, Intangible	113
Closing costs - expensed	$ 3
Connecticut, 1 Property Acquired 3/17/2014 [Member]
Property Acquisitions [Line Items]
Number of Properties \| Property	1
Total Consideration Paid	$ 15,138
Cash Consideration Paid	15,169
Loan Assumed	0
Non-cash gain	0
Previous equity interest	0
Net Liabilities (Assets) Assumed	(31)
Value of OP units issued	$ 0
Number of OP Units Issued \| shares	0
Acquisition Date Fair Value, Land	$ 1,072
Acquisition Date Fair Value, Building	14,028
Acquisition Date Fair Value, Intangible	0
Closing costs - expensed	$ 38
Alabama, 1 Property Acquired 3/20/2014 [Member]
Property Acquisitions [Line Items]
Number of Properties \| Property	1
Total Consideration Paid	$ 13,813
Cash Consideration Paid	13,752
Loan Assumed	0
Non-cash gain	0
Previous equity interest	0
Net Liabilities (Assets) Assumed	61
Value of OP units issued	$ 0
Number of OP Units Issued \| shares	0
Acquisition Date Fair Value, Land	$ 2,381
Acquisition Date Fair Value, Building	11,224
Acquisition Date Fair Value, Intangible	200
Closing costs - expensed	$ 8
Georgia, 1 Property Acquired 4/3/2014 [Member]
Property Acquisitions [Line Items]
Number of Properties \| Property	1
Total Consideration Paid	$ 23,649
Cash Consideration Paid	15,158
Loan Assumed	0
Non-cash gain	0
Previous equity interest	0
Net Liabilities (Assets) Assumed	157
Value of OP units issued	$ 8,334
Number of OP Units Issued \| shares	333,360
Acquisition Date Fair Value, Land	$ 2,961
Acquisition Date Fair Value, Building	19,819
Acquisition Date Fair Value, Intangible	242
Closing costs - expensed	$ 627
Florida, 1 Property Acquired 4/15/2014 [Member]
Property Acquisitions [Line Items]
Number of Properties \| Property	1
Total Consideration Paid	$ 10,186
Cash Consideration Paid	10,077
Loan Assumed	0
Non-cash gain	0
Previous equity interest	0
Net Liabilities (Assets) Assumed	109
Value of OP units issued	$ 0
Number of OP Units Issued \| shares	0
Acquisition Date Fair Value, Land	$ 1,640
Acquisition Date Fair Value, Building	8,358
Acquisition Date Fair Value, Intangible	149
Closing costs - expensed	$ 39
California, 3 Properties Acquired 4/25/2014 [Member]
Property Acquisitions [Line Items]
Number of Properties \| Property	3
Total Consideration Paid	$ 35,275
Cash Consideration Paid	2,726
Loan Assumed	19,111
Non-cash gain	3,438
Previous equity interest	129
Net Liabilities (Assets) Assumed	(580)
Value of OP units issued	$ 10,451
Number of OP Units Issued \| shares	226,285
Acquisition Date Fair Value, Land	$ 6,853
Acquisition Date Fair Value, Building	27,666
Acquisition Date Fair Value, Intangible	579
Closing costs - expensed	$ 177
Washington, 1 Property Acquired 4/30/2014 [Member]
Property Acquisitions [Line Items]
Number of Properties \| Property	1
Total Consideration Paid	$ 4,388
Cash Consideration Paid	4,388
Loan Assumed	0
Non-cash gain	0
Previous equity interest	0
Net Liabilities (Assets) Assumed	0
Value of OP units issued	$ 0
Number of OP Units Issued \| shares	0
Acquisition Date Fair Value, Land	$ 437
Acquisition Date Fair Value, Building	3,808
Acquisition Date Fair Value, Intangible	102
Closing costs - expensed	$ 41
California, 1 Property Acquired 5/28/2014 [Member]
Property Acquisitions [Line Items]
Number of Properties \| Property	1
Total Consideration Paid	$ 17,614
Cash Consideration Paid	294
Loan Assumed	14,079
Non-cash gain	0
Previous equity interest	0
Net Liabilities (Assets) Assumed	(92)
Value of OP units issued	$ 3,333
Number of OP Units Issued \| shares	69,735
Acquisition Date Fair Value, Land	$ 4,707
Acquisition Date Fair Value, Building	12,604
Acquisition Date Fair Value, Intangible	265
Closing costs - expensed	$ 38
North Carolina, 1 Property Acquired 6/18/2014 [Member]
Property Acquisitions [Line Items]
Number of Properties \| Property	1
Total Consideration Paid	$ 7,310
Cash Consideration Paid	7,307
Loan Assumed	0
Non-cash gain	0
Previous equity interest	0
Net Liabilities (Assets) Assumed	3
Value of OP units issued	$ 0
Number of OP Units Issued \| shares	0
Acquisition Date Fair Value, Land	$ 2,940
Acquisition Date Fair Value, Building	4,265
Acquisition Date Fair Value, Intangible	93
Closing costs - expensed	$ 12
Georgia, 1 Property Acquired 8/6/2014 [Member]
Property Acquisitions [Line Items]
Number of Properties \| Property	1
Total Consideration Paid	$ 11,337
Cash Consideration Paid	11,290
Loan Assumed	0
Non-cash gain	0
Previous equity interest	0
Net Liabilities (Assets) Assumed	47
Value of OP units issued	$ 0
Number of OP Units Issued \| shares	0
Acquisition Date Fair Value, Land	$ 1,132
Acquisition Date Fair Value, Building	10,080
Acquisition Date Fair Value, Intangible	111
Closing costs - expensed	$ 14
Texas, 1 Property Acquired 8/8/2014 [Member]
Property Acquisitions [Line Items]
Number of Properties \| Property	1
Total Consideration Paid	$ 11,246
Cash Consideration Paid	6,134
Loan Assumed	5,157
Non-cash gain	0
Previous equity interest	0
Net Liabilities (Assets) Assumed	(45)
Value of OP units issued	$ 0
Number of OP Units Issued \| shares	0
Acquisition Date Fair Value, Land	$ 1,047
Acquisition Date Fair Value, Building	9,969
Acquisition Date Fair Value, Intangible	181
Closing costs - expensed	$ 49
Florida, 1 Property Acquired 9/3/2014 [Member]
Property Acquisitions [Line Items]
Number of Properties \| Property	1
Total Consideration Paid	$ 4,259
Cash Consideration Paid	4,225
Loan Assumed	0
Non-cash gain	0
Previous equity interest	0
Net Liabilities (Assets) Assumed	34
Value of OP units issued	$ 0
Number of OP Units Issued \| shares	0
Acquisition Date Fair Value, Land	$ 529
Acquisition Date Fair Value, Building	3,604
Acquisition Date Fair Value, Intangible	81
Closing costs - expensed	$ 45

Property Acquisitions and Dispositions - Schedule of Operating Properties Acquired (Parenthetical) (Detail) $ in Thousands		9 Months Ended
	Mar. 05, 2014 USD ($)	Sep. 30, 2014 USD ($) Property shares	Sep. 30, 2013 USD ($)
Property Acquisitions [Line Items]
Non-cash gain		$ 3,438	$ 2,556
California, 1 Property Acquired 3/4/2014 [Member]
Property Acquisitions [Line Items]
Amount paid for land portion of property acquired	$ 2,150
Non-cash gain		$ 0
California, 3 Properties Acquired 4/25/2014 [Member]
Property Acquisitions [Line Items]
Number of properties in which interests were acquired \| Property		2
Additional interest acquired in the venture		60.00%
Equity ownership prior to the acquisition		40.00%
Previous equity interest, fair value		$ 3,567
Non-cash gain		$ 3,438
Series C Units [Member]
Property Acquisitions [Line Items]
Preferred OP units issued as part of the acquisition (in shares) \| shares		226,285
Preferred OP units issued as part of the acquisition		$ 10,451

Property Acquisitions and Dispositions - Additional Information (Detail) $ in Thousands				3 Months Ended		9 Months Ended
	Sep. 26, 2013 USD ($) shares	Aug. 29, 2013 Property	May 16, 2013 USD ($)	Sep. 30, 2014 USD ($)	Sep. 30, 2013 USD ($)	Sep. 30, 2014 USD ($)	Sep. 30, 2013 USD ($)
Property Acquisitions [Line Items]
Loans Assumed						$ 38,347	$ 7,122
Defeasance costs				$ 0	$ (9,153)	$ 0	$ (9,153)
Operating Partnership [Member]
Property Acquisitions [Line Items]
Number of self-storage facilities (properties) acquired \| Property		19
Number of self storage properties \| Property		20
Cash portion of payment for acquisition	$ 100,876
Loans Assumed	$ 98,960
Number of common units issued as part of acquisition \| shares	1,448,108
OP units issued as part of the acquisition	$ 62,341
Defeasance costs	$ 9,153
Operating Partnership [Member] \| Series B Units [Member]
Property Acquisitions [Line Items]
Preferred OP units issued as part of the acquisition (in shares) \| shares	1,342,727
Preferred OP units issued as part of the acquisition	$ 33,568
Operating Partnership [Member] \| New York [Member]
Property Acquisitions [Line Items]
Property sold			$ 950

Gain (Loss) on Sale of Real Estate and Earnout from Prior Acquisition - Additional information (Detail) $ in Thousands	1 Months Ended	9 Months Ended	12 Months Ended
	Jun. 30, 2013 USD ($) Property	Sep. 30, 2014 USD ($) Property	Dec. 31, 2012 Property	Dec. 31, 2011 USD ($)
Gain (Loss) On Sale Of Real Estate And Earnout From Prior Acquisition [Line Items]
Number of Properties \| Property		32
Number of self storage property which portion of land condemned \| Property	1
California [Member]
Gain (Loss) On Sale Of Real Estate And Earnout From Prior Acquisition [Line Items]
Gain on condemnation of a portion of land \| $	$ 800
New York and New Jersey, 10 Properties Acquired in 2012 [Member]
Gain (Loss) On Sale Of Real Estate And Earnout From Prior Acquisition [Line Items]
Number of Properties \| Property			10
Term to make additional cash payment to sellers if the properties acquired exceeded a specified amount of net rental income			2 years
Payment to sellers resulting from higher rental income of properties \| $		$ 7,785
Florida, Properties Acquired in 2011 [Member]
Gain (Loss) On Sale Of Real Estate And Earnout From Prior Acquisition [Line Items]
Term to make additional cash payment to sellers if the properties acquired exceeded a specified amount of net rental income				12 months
Payment to sellers resulting from higher rental income of properties \| $				$ 2,500

Variable Interests - Additional Information (Detail)	9 Months Ended
Variable Interests - Additional Information (Detail)	Sep. 30, 2014 Item JointVenture
Variable Interests And Equity Method Investments Disclosure [Abstract]
Number of interests in unconsolidated VIE joint ventures	1
Equity Ownership (as a percent)	18.00%
Profit interest (as a percent)	50.00%
Voting rights in unconsolidated VIE joint ventures (as a percent)	50.00%
Management fees charged from unconsolidated VIE (as a percent)	6.00%
Number of wholly-owned unconsolidated subsidiaries \| Item	3
Number of interests in consolidated VIE joint ventures	0

Variable Interests - Schedule of the Comparison of the Liability Balance and the Maximum Exposure to Loss Related to the Company's each VIE (Detail) - Extra Space Of Sacramento One LLC [Member] $ in Thousands	Sep. 30, 2014 USD ($)
Variable Interest Entity [Line Items]
Liability Balance	$ 0
Investment Balance	(1,232)
Amounts Payable to the Company	10,726
Maximum Exposure to Loss	9,494
Difference	$ (9,494)

Variable Interests - Schedule of the Liabilities and the Maximum Exposure to Loss Related to the Trusts (Detail) - USD ($) $ in Thousands	Sep. 30, 2014	Dec. 31, 2013
Variable Interest Entity [Line Items]
Notes payable to trusts	$ 119,590	$ 119,590
Operating Partnership [Member] \| Variable Interest Entity, Not Primary Beneficiary [Member]
Variable Interest Entity [Line Items]
Notes payable to trusts	119,590
Investment Balance	3,590
Maximum Exposure to Loss	116,000
Difference	0
Operating Partnership [Member] \| Variable Interest Entity, Not Primary Beneficiary [Member] \| Trust [Member]
Variable Interest Entity [Line Items]
Notes payable to trusts	36,083
Investment Balance	1,083
Maximum Exposure to Loss	35,000
Difference	0
Operating Partnership [Member] \| Variable Interest Entity, Not Primary Beneficiary [Member] \| Trust II [Member]
Variable Interest Entity [Line Items]
Notes payable to trusts	42,269
Investment Balance	1,269
Maximum Exposure to Loss	41,000
Difference	0
Operating Partnership [Member] \| Variable Interest Entity, Not Primary Beneficiary [Member] \| Trust III [Member]
Variable Interest Entity [Line Items]
Notes payable to trusts	41,238
Investment Balance	1,238
Maximum Exposure to Loss	40,000
Difference	$ 0

Derivatives - Additional Information (Detail) $ in Thousands	Sep. 30, 2014 USD ($) Item
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Number of derivative financial instruments \| Item	20
Credit risk derivative, fair value of derivatives in a net liability position	$ 1,818
Estimated termination value on settlement	$ 2,003

Derivatives - Schedule Summarizing the Terms of Entity's Derivative Financial Instruments (Detail) - Cash Flow Hedging [Member] - Interest Rate Swap [Member] $ in Thousands	Sep. 30, 2014 USD ($)
Derivative [Line Items]
Strike rate cash flow hedge swap agreements, low end of range (as a percent)	2.79%
Strike rate cash flow hedge swap agreements, high end of range (as a percent)	6.12%
Minimum [Member]
Derivative [Line Items]
Notional Amounts	$ 4,687
Maximum [Member]
Derivative [Line Items]
Notional Amounts	$ 95,004

Derivatives - Schedule of Balance Sheet Classification and Fair Value of the Entity's Derivative Financial Instruments (Detail) - USD ($) $ in Thousands	Sep. 30, 2014	Dec. 31, 2013
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Other assets - Fair Value of Swap Agreements	$ 7,317	$ 13,630
Other liabilities - Fair Value of Swap Agreements	$ (1,818)	$ (3,684)

Derivatives - Interest Payments Recognized as an Increase or Decrease in Interest Expense (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Interest Rate Swap [Member]
Derivative [Line Items]
Swap agreements increase (decrease) in interest expenses due to interest payments	$ (2,172)	$ (2,307)	$ (6,782)	$ (6,589)

Derivatives - Schedule of Information Relating to the Gain (Loss) Recognized on the Swap Agreements (Detail) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Swap agreements gain (loss) recognized in OCI	$ (11,099)	$ 10,837
Swap agreements gain (loss) reclassified from OCI - Interest expense	$ (6,782)	$ (6,589)

Exchangeable Senior Notes - Additional Information (Detail) - USD ($) $ in Thousands	Jun. 21, 2013	Sep. 30, 2014
Debt Instrument [Line Items]
Effective interest rate on the liability component (as a percent)		4.00%
2.375% Exchangeable Senior Notes [Member] \| Operating Partnership [Member]
Debt Instrument [Line Items]
Principal amount of notes issued	$ 250,000	$ 250,000
Interest rate (as a percent)	2.375%	2.375%
Discount rate (as a percent)	1.50%
Issuance cost	$ 1,672
Amortization period	5 years
Conversion ratio, number of shares per $1,000 principal amount, numerator	17.98
Principal amount used for debt instrument conversion ratio	$ 1,000
Unamortized cash discount	$ 3,750
Redemption price as percentage of principal amount of notes plus accrued and unpaid interest	100.00%
Redemption price as percentage of principal amount of notes at request of debt holders and upon occurrence of designated event	100.00%
Minimum [Member] \| 2.375% Exchangeable Senior Notes [Member] \| Operating Partnership [Member]
Debt Instrument [Line Items]
Number of days of written notice to holders of notes required for redemption	30 days
Maximum [Member] \| 2.375% Exchangeable Senior Notes [Member] \| Operating Partnership [Member]
Debt Instrument [Line Items]
Number of days of written notice to holders of notes required for redemption	60 days

Exchangeable Senior Notes - Schedule of Information about the Carrying Amount of the Equity Component, the Principal Amount of the Liability Component, Unamortized Discount and Net Carrying Amount for the Notes (Detail) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2014	Dec. 31, 2013
Debt Instrument [Line Items]
Principal amount of liability component	$ 250,000	$ 250,000
Unamortized cash discount	(13,920)	(16,487)
Operating Partnership [Member] \| 2.375% Exchangeable Senior Notes [Member]
Debt Instrument [Line Items]
Carrying amount of equity component	14,496	14,496
Principal amount of liability component	250,000	250,000
Unamortized discount-equity component	(11,127)	(13,131)
Unamortized cash discount	(2,793)	(3,356)
Net carrying amount of liability component	$ 236,080	$ 233,513

Exchangeable Senior Notes - Summary of Amount of Interest Cost Recognized Relating to the Contractual Interest Rate and the Amortization of the Discount on the Liability Component of the Notes (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Debt Instrument [Line Items]
Amortization of discount	$ 679	$ 834	$ 2,004	$ 947
2033 Notes and 2027 Notes [Member]
Debt Instrument [Line Items]
Contractual interest	1,484	1,484	4,452	1,632
Amortization of discount	679	834	2,004	947
Total interest expense recognized	$ 2,163	$ 2,318	$ 6,456	$ 2,579

Noncontrolling Interest Represented by Preferred Operating Partnership Units - Series A Participating Redeemable Preferred Units - Additional Information (Detail) $ in Thousands			1 Months Ended	9 Months Ended
	Nov. 06, 2014 USD ($) shares	Aug. 29, 2013 Property	Jun. 30, 2007 Property shares	Sep. 30, 2014 USD ($)	Dec. 31, 2013 USD ($)	Jun. 25, 2007 USD ($)
Noncontrolling Interest in Operating Partnership [Line Items]
Loan to holders of preferred OP units				$ 100,000	$ 100,000
Operating Partnership [Member]
Noncontrolling Interest in Operating Partnership [Line Items]
Number of self-storage facilities (properties) acquired \| Property		19
Operating Partnership [Member] \| Series A Participating Redeemable Preferred Units [Member]
Noncontrolling Interest in Operating Partnership [Line Items]
Number of self-storage facilities (properties) acquired \| Property			10
Operating Partnership [Member] \| Series A Participating Redeemable Preferred Units [Member] \| Series A Units [Member]
Noncontrolling Interest in Operating Partnership [Line Items]
Preferred Units Issued as Part of Acquisition (in shares) \| shares			989,980
Fixed priority return on preferred OP units, stated return rate (as a percent)				5.00%
Fixed priority return on preferred OP units, amount				$ 115,000
Fixed priority return on preferred OP units, liquidation value				$ 115,000
Operating Partnership Holders of A units [Member] \| Series A Participating Redeemable Preferred Units [Member]
Noncontrolling Interest in Operating Partnership [Line Items]
Loan to holders of preferred OP units						$ 100,000
Note receivable interest rate (as a percent)			4.85%
Maximum number of preferred OP units converted prior to the maturity date of the loan (in shares) \| shares			114,500
Operating Partnership Holders of A units [Member] \| Series A Participating Redeemable Preferred Units [Member] \| Subsequent Event [Member]
Noncontrolling Interest in Operating Partnership [Line Items]
A units redeemed \| shares	114,500
A units redeemed ,value	$ 4,794
Common stock shares redeemed \| shares	280,331
Common stock value redeemed	$ 19,175

Noncontrolling Interest Represented by Preferred Operating Partnership Units - Series B Redeemable Preferred Units - Additional Information (Detail) $ / shares in Units, $ in Thousands				9 Months Ended
	Apr. 03, 2014 USD ($) shares	Sep. 26, 2013 USD ($) shares	Aug. 29, 2013 Property	Sep. 30, 2014 USD ($) $ / shares	Sep. 30, 2013 USD ($)
Noncontrolling Interest in Operating Partnership [Line Items]
Total Consideration Paid				$ 375,994
Debt assumed				38,347	$ 7,122
Operating Partnership [Member]
Noncontrolling Interest in Operating Partnership [Line Items]
Number of self-storage facilities (properties) acquired \| Property			19
Number of self-storage properties acquired as part of portfolio acquisition \| Property			20
Cash portion of payment for acquisition		$ 100,876
Debt assumed		$ 98,960
Number of common units issued as part of acquisition \| shares		1,448,108
OP units issued as part of the acquisition		$ 62,341
Operating Partnership [Member] \| Series B Units [Member]
Noncontrolling Interest in Operating Partnership [Line Items]
Preferred OP units issued as part of the acquisition (in shares) \| shares		1,342,727
Preferred OP units issued as part of the acquisition		$ 33,568
Georgia, 1 Property Acquired 4/3/2014 [Member]
Noncontrolling Interest in Operating Partnership [Line Items]
Total Consideration Paid				23,649
Debt assumed				$ 0
Series B Redeemable Preferred Units [Member] \| Series B Units [Member]
Noncontrolling Interest in Operating Partnership [Line Items]
Liquidation value (in dollars per share) \| $ / shares				$ 25.00
Fixed liquidation value				$ 41,902
Annual rate of return (as a percent)				6.00%
Series B Redeemable Preferred Units [Member] \| Georgia, 1 Property Acquired 4/3/2014 [Member] \| Series B Units [Member]
Noncontrolling Interest in Operating Partnership [Line Items]
Total Consideration Paid	$ 8,334
Preferred OP units issued as part of the acquisition (in shares) \| shares	333,360
Series B Redeemable Preferred Units [Member] \| Georgia, 1 Property Acquired 4/3/2014 [Member] \| Operating Partnership [Member]
Noncontrolling Interest in Operating Partnership [Line Items]
Total Consideration Paid	$ 15,158
Series B Redeemable Preferred Units [Member] \| California, 20 Properties Acquired 2013-September [Member] \| Operating Partnership [Member]
Noncontrolling Interest in Operating Partnership [Line Items]
Number of self-storage facilities (properties) acquired \| Property			19
Number of self-storage properties acquired as part of portfolio acquisition \| Property			20
Cash portion of payment for acquisition		100,876
Debt assumed		$ 98,960
Number of common units issued as part of acquisition \| shares		1,448,108
OP units issued as part of the acquisition		$ 62,341
Series B Redeemable Preferred Units [Member] \| California, 20 Properties Acquired 2013-September [Member] \| Operating Partnership [Member] \| Series B Units [Member]
Noncontrolling Interest in Operating Partnership [Line Items]
Preferred OP units issued as part of the acquisition (in shares) \| shares		1,342,727
Preferred OP units issued as part of the acquisition		$ 33,568

Noncontrolling Interest Represented by Preferred Operating Partnership Units - Series C Convertible Redeemable Preferred Units - Additional Information (Detail) $ / shares in Units, $ in Thousands						9 Months Ended
	May 28, 2014 USD ($) shares	Dec. 02, 2013 Property	Nov. 19, 2013 Property	Sep. 26, 2013 USD ($)	Aug. 29, 2013 Property	Sep. 30, 2014 USD ($) OperatingPartnershipUnits $ / shares shares	Sep. 30, 2013 USD ($)
Noncontrolling Interest in Operating Partnership [Line Items]
Debt assumed						$ 38,347	$ 7,122
Operating Partnership [Member]
Noncontrolling Interest in Operating Partnership [Line Items]
Number of self-storage facilities (properties) acquired \| Property					19
Cash portion of payment for acquisition				$ 100,876
Debt assumed				$ 98,960
Series C Units [Member]
Noncontrolling Interest in Operating Partnership [Line Items]
Preferred Units Issued as Part of Acquisition (in shares) \| shares						226,285
Preferred OP units issued as part of the acquisition						$ 10,451
Series C Convertible Redeemable Preferred Units [Member] \| Series C Units [Member]
Noncontrolling Interest in Operating Partnership [Line Items]
Liquidation value (in dollars per share) \| $ / shares						$ 42.10
Fixed liquidation value						$ 29,639
Quarterly distribution per preferred OP unit payable above quarterly distribution for common OP Unit \| $ / shares						$ 0.18
Number of quarters immediately preceding the fifth anniversary of issuance for which distribution is payable						12 months
Period from date of issuance after which preferred OP units will become redeemable at the option of the holder						1 year
Period from date of issuance after which preferred OP units will become convertible into common OP units at the option of the holder						1 year
Preferred OP units conversion ratio \| OperatingPartnershipUnits						0.9145
California, Properties Acquired December 2013 [Member] \| Series C Convertible Redeemable Preferred Units [Member]
Noncontrolling Interest in Operating Partnership [Line Items]
Number of separate Contribution Agreements \| Property			12
Ownership interest in five properties through joint ventures prior to the acquisition		35.00%
Ownership interest in one property through joint ventures prior to the acquisition		40.00%
Number of self-storage properties in which ownership interest was held prior to acquisition \| Property		1
Number of self-storage properties in which ownership interest was held prior to acquisition of remaining properties \| Property		5
California, Properties Acquired December 2013 [Member] \| Series C Convertible Redeemable Preferred Units [Member] \| Operating Partnership [Member]
Noncontrolling Interest in Operating Partnership [Line Items]
Number of self-storage facilities (properties) acquired \| Property		6
Cash portion of payment for acquisition	$ 45,722
Debt assumed	$ 37,532
California, Properties Acquired December 2013 [Member] \| Series C Convertible Redeemable Preferred Units [Member] \| Series C Units [Member] \| Operating Partnership [Member]
Noncontrolling Interest in Operating Partnership [Line Items]
Preferred Units Issued as Part of Acquisition (in shares) \| shares	704,016
Preferred OP units issued as part of the acquisition	$ 30,960

Noncontrolling Interest in Operating Partnership - Additional Information (Detail) $ / shares in Units, $ in Thousands	9 Months Ended
	Sep. 30, 2014 USD ($) $ / shares shares
Noncontrolling Interest in Operating Partnership [Line Items]
Period used as a denomination to determine the average closing price of common stock	10 days
OP units conversion basis	One-for-one basis
Ten day average closing stock price (in dollars per share) \| $ / shares	$ 51.31
Consideration to be paid on redemption of common OP units \| $	$ 222,384
Operating Partnership [Member]
Noncontrolling Interest in Operating Partnership [Line Items]
Ownership interest held by entity (as a percent)	93.80%
Noncontrolling interest in operating partnership (as a percent)	6.20%
OP units outstanding (in shares) \| shares	4,334,118

Other Noncontrolling Interests - Additional Information (Detail) $ in Thousands	1 Months Ended
	May 31, 2013 USD ($)	Feb. 28, 2013 USD ($) Property	Sep. 30, 2014 Property JointVenture
Noncontrolling Interest in Operating Partnership [Line Items]
Number of properties under construction			1
Number of operating properties owned by consolidated joint venture			19
Number of joint venture partners in a consolidated property in which ownership interest was acquired		1
Purchase of capital interest by entity in a joint venture partner of a consolidated property	27.70%	1.70%
Purchase of profit interest by the entity in a joint venture partner of a consolidated property	35.00%	17.00%
Cash paid for acquiring interest in a joint venture partner of a consolidated property \| $	$ 950	$ 200
Ownership interest held by entity in joint venture partner of a consolidated property prior to acquisition		95.00%
Ownership interest held by entity in joint venture partner of a consolidated property		96.70%
Other [Member]
Noncontrolling Interest in Operating Partnership [Line Items]
Number of consolidated joint ventures \| JointVenture			2
Other [Member] \| Minimum [Member]
Noncontrolling Interest in Operating Partnership [Line Items]
Ownership interests of third party owners			1.00%
Other [Member] \| Maximum [Member]
Noncontrolling Interest in Operating Partnership [Line Items]
Ownership interests of third party owners			3.30%

Equity in Earnings of Unconsolidated Real Estate Ventures - Purchase of Joint Venture Partners' Interests - Additional Information (Detail) $ in Thousands		3 Months Ended		5 Months Ended	9 Months Ended
	Feb. 13, 2013 USD ($) Property	Sep. 30, 2014 USD ($) Property	Sep. 30, 2013 USD ($)	May 31, 2014 Property JointVenture	Sep. 30, 2014 USD ($) Property	Sep. 30, 2013 USD ($)
Real Estate Joint Ventures of the Entity [Line Items]
Number of properties owned by joint venture \| Property		19			19
Non-cash gain					$ 3,438
Equity in earnings of unconsolidated real estate ventures-gain on purchase of joint venture partners' interests		$ 378	$ 0		$ 3,816	$ 2,556
Grupe Acquisition [Member]
Real Estate Joint Ventures of the Entity [Line Items]
Number of properties owned by joint venture \| Property				6
Number of joint ventures with Grupe \| JointVenture				6
Grupe Acquisition [Member] \| Minimum [Member]
Real Estate Joint Ventures of the Entity [Line Items]
Ownership interest acquired in joint venture (as a percent)				60.00%
Ownership interest in properties through joint ventures prior to the acquisition				35.00%
Equity ownership prior to the acquisition (as a percent)				35.00%
Grupe Acquisition [Member] \| Maximum [Member]
Real Estate Joint Ventures of the Entity [Line Items]
Ownership interest acquired in joint venture (as a percent)				65.00%
Ownership interest in properties through joint ventures prior to the acquisition				40.00%
Equity ownership prior to the acquisition (as a percent)				40.00%
Extra Space of Eastern Avenue LLC [Member]
Real Estate Joint Ventures of the Entity [Line Items]
Ownership interest acquired in joint venture (as a percent)	48.00%
Number of properties owned by joint venture \| Property	1
Equity ownership prior to the acquisition (as a percent)	52.00%
Non-cash gain	$ 2,215
Cash paid for acquiring equity interest in the joint venture	$ 5,979
Extra Space of Montrose Avenue LLC [Member]
Real Estate Joint Ventures of the Entity [Line Items]
Ownership interest acquired in joint venture (as a percent)	61.00%
Number of properties owned by joint venture \| Property	1
Equity ownership prior to the acquisition (as a percent)	39.00%
Non-cash gain	$ 341
Cash paid for acquiring equity interest in the joint venture	$ 6,878

Segment Information - Additional Information (Detail)	9 Months Ended
Segment Information - Additional Information (Detail)	Sep. 30, 2014 Segments
Segment Reporting [Abstract]
Number of reportable segments	3

Segment Information - Schedule of Financial Information of Business Segments (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
Segment Reporting Information [Line Items]
Investment in unconsolidated real estate ventures	$ 86,232		$ 86,232		$ 88,125
Total assets	4,225,895		4,225,895		3,977,140
Total revenues	167,368	$ 133,111	479,788	$ 378,679
Operating expenses, including depreciation and amortization	89,875	77,047	271,236	222,511
Income (loss) from operations	77,493	56,064	208,552	156,168
Gain (loss) on sale of real estate and earnout from prior acquisitions	(2,500)	0	(10,285)	800
Interest income	186	202	1,167	519
Loss on extinguishment of debt related to portfolio acquisition	0	(9,153)	0	(9,153)
Interest expense	(20,681)	(16,264)	(60,937)	(51,992)
Non-cash interest expense related to the amortization of discount on equity component of exchangeable senior notes	(679)	(834)	(2,004)	(947)
Interest income on note receivable from Preferred Operating Partnership unit holder	1,213	1,213	3,638	3,638
Equity in earnings of unconsolidated real estate ventures	2,777	3,405	7,800	8,942
Equity in earnings of unconsolidated real estate ventures - gain on purchase of joint venture partners' interests	378	0	3,816	2,556
Income tax (expense) benefit	1,006	(2,281)	(5,337)	(7,147)
Net income (loss)	59,193	32,352	146,410	103,384
Depreciation and amortization expense	29,249	23,428	85,895	69,238
Acquisition of real estate assets			(328,235)	(82,949)
Development and redevelopment of real estate assets			(11,288)	(3,941)
Rental Operations [Member]
Segment Reporting Information [Line Items]
Investment in unconsolidated real estate ventures	86,232		86,232		88,125
Total assets	3,960,422		3,960,422		3,641,746
Total revenues	144,669	113,881	415,448	324,144
Operating expenses, including depreciation and amortization	70,520	56,428	209,082	167,300
Income (loss) from operations	74,149	57,453	206,366	156,844
Gain (loss) on sale of real estate and earnout from prior acquisitions	0	0	0	800
Interest expense	(20,416)	(15,608)	(60,074)	(50,657)
Equity in earnings of unconsolidated real estate ventures	2,777	3,405	7,800	8,942
Equity in earnings of unconsolidated real estate ventures - gain on purchase of joint venture partners' interests	378	0	3,816	2,556
Income tax (expense) benefit	(222)	334	(914)	(134)
Net income (loss)	56,666	45,584	156,994	118,351
Depreciation and amortization expense	27,226	22,052	80,012	65,025
Tenant Reinsurance [Member]
Segment Reporting Information [Line Items]
Total assets	32,520		32,520		34,393
Total revenues	15,385	12,294	43,356	34,625
Operating expenses, including depreciation and amortization	2,930	2,873	8,133	6,985
Income (loss) from operations	12,455	9,421	35,223	27,640
Interest income	5	5	13	13
Income tax (expense) benefit	2,011	(3,300)	(5,660)	(12,545)
Net income (loss)	14,471	6,126	29,576	15,108
Property Management Acquisition and Development [Member]
Segment Reporting Information [Line Items]
Total assets	232,933		232,933		$ 301,001
Total revenues	7,314	6,936	20,984	19,910
Operating expenses, including depreciation and amortization	16,425	17,746	54,021	48,226
Income (loss) from operations	(9,111)	(10,810)	(33,037)	(28,316)
Gain (loss) on sale of real estate and earnout from prior acquisitions	(2,500)	0	(10,285)	0
Interest income	181	197	1,154	506
Loss on extinguishment of debt related to portfolio acquisition	0	(9,153)	0	(9,153)
Interest expense	(265)	(656)	(863)	(1,335)
Non-cash interest expense related to the amortization of discount on equity component of exchangeable senior notes	(679)	(834)	(2,004)	(947)
Interest income on note receivable from Preferred Operating Partnership unit holder	1,213	1,213	3,638	3,638
Income tax (expense) benefit	(783)	685	1,237	5,532
Net income (loss)	(11,944)	(19,358)	(40,160)	(30,075)
Depreciation and amortization expense	2,023	1,376	5,883	4,213
Acquisition of real estate assets	(31,315)	(23,245)	(328,235)	(82,949)
Development and redevelopment of real estate assets	$ (5,330)	$ (1,609)	$ (11,288)	$ (3,941)

Subsequent Events - Additional Information (Detail) $ in Thousands			9 Months Ended
	Oct. 24, 2014 USD ($) Property	Oct. 22, 2014 USD ($) Property	Sep. 30, 2014 USD ($)
Subsequent Event [Line Items]
Total Consideration Paid			$ 375,994
Subsequent Event [Member] \| GEORGIA
Subsequent Event [Line Items]
Number of self storage properties Purchased \| Property		1
Total Consideration Paid		$ 11,000
Subsequent Event [Member] \| COLORADO
Subsequent Event [Line Items]
Number of self storage properties Purchased \| Property	1,000
Total Consideration Paid	$ 6,250