Life Storage Inc - Registered Shares (LSI) 10-Q 6 Nov 13 2013 Q3 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	9 Months Ended
	Sep. 30, 2013	Oct. 31, 2013
Document And Entity Information [Abstract]	'	'
Document Type	'10-Q	'
Amendment Flag	'false	'
Document Period End Date	30-Sep-13	'
Document Fiscal Year Focus	'2013	'
Document Fiscal Period Focus	'Q3	'
Entity Registrant Name	'SOVRAN SELF STORAGE INC	'
Entity Central Index Key	'0000944314	'
Current Fiscal Year End Date	'--12-31	'
Entity Filer Category	'Large Accelerated Filer	'
Entity Common Stock, Shares Outstanding	'	32,014,215

Consolidated_Balance_Sheets

Consolidated Balance Sheets (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Investment in storage facilities:	'	'
Land	$306,879	$299,544
Building, equipment, and construction in progress	1,513,232	1,456,410
Real estate investment property, at cost, total	1,820,111	1,755,954
Less: accumulated depreciation	-360,061	-328,952
Investment in storage facilities, net	1,460,050	1,427,002
Cash and cash equivalents	9,662	7,255
Accounts receivable	3,583	3,450
Receivable from unconsolidated joint ventures	782	856
Investment in unconsolidated joint ventures	37,841	34,255
Prepaid expenses	5,594	4,947
Fair value of interest rate swap agreements	166	'
Other assets	5,584	6,676
Total Assets	1,523,262	1,484,441
Liabilities	'	'
Line of credit	49,000	105,000
Term notes	575,000	575,000
Accounts payable and accrued liabilities	33,263	36,667
Deferred revenue	6,919	6,416
Fair value of interest rate swap agreements	10,524	15,707
Mortgages payable	3,242	4,251
Total Liabilities	677,948	743,041
Noncontrolling redeemable Operating Partnership Units at redemption value	14,916	12,670
Shareholders' Equity	'	'
Common stock $.01 par value, 100,000,000 shares authorized, 31,977,890 shares outstanding at September 30, 2013 (30,446,620 at December 31, 2012)	331	316
Additional paid-in capital	1,037,016	943,604
Dividends in excess of net income	-169,721	-172,773
Accumulated other comprehensive loss	-10,053	-15,242
Treasury stock at cost, 1,171,886 shares	-27,175	-27,175
Total Shareholders' Equity	830,398	728,730
Total Liabilities and Shareholders' Equity	$1,523,262	$1,484,441

Consolidated_Balance_Sheets_Pa

Consolidated Balance Sheets (Parenthetical) (USD $)	Sep. 30, 2013	Dec. 31, 2012
Statement Of Financial Position [Abstract]	'	'
Common stock, par value	$0.01	$0.01
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares outstanding	31,977,890	30,446,620
Treasury stock at cost, shares	1,171,886	1,171,886

Consolidated_Statements_of_Ope

Consolidated Statements of Operations (USD $)	3 Months Ended		9 Months Ended
In Thousands, except Share data, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Revenues	'	'	'	'
Rental income	$65,806	$57,574	$188,402	$161,857
Other operating income	5,176	4,200	14,530	12,018
Total operating revenues	70,982	61,774	202,932	173,875
Expenses	'	'	'	'
Property operations and maintenance	15,720	14,319	45,738	40,993
Real estate taxes	6,994	5,629	19,858	16,635
General and administrative	8,965	8,172	26,745	23,707
Acquisition costs	776	1,075	1,263	2,382
Depreciation and amortization	11,381	10,427	34,118	30,461
Total operating expenses	43,836	39,622	127,722	114,178
Income from operations	27,146	22,152	75,210	59,697
Other income (expenses)	'	'	'	'
Interest expense	-7,923	-8,350	-24,827	-24,914
Interest income	1	'	2	3
Gain on sale of real estate	'	'	421	'
Equity in income of joint ventures	575	335	1,417	608
Income from continuing operations	19,799	14,137	52,223	35,394
Income from discontinued operations (including gain on disposal of $4,498 in 2012)	'	4,821	0	6,693
Net income	19,799	18,958	52,223	42,087
Net income attributable to noncontrolling interest	-124	-151	-331	-421
Net income attributable to common shareholders	$19,675	$18,807	$51,892	$41,666
Earnings per common share attributable to common shareholders - basic	'	'	'	'
Continuing operations	$0.63	$0.48	$1.67	$1.20
Discontinued operations	'	$0.16	'	$0.23
Earnings per share - basic	$0.63	$0.64	$1.67	$1.43
Earnings per common share attributable to common shareholders - diluted	'	'	'	'
Continuing operations	$0.62	$0.47	$1.66	$1.20
Discontinued operations	'	$0.16	'	$0.23
Earnings per share - diluted	$0.62	$0.63	$1.66	$1.43
Common shares used in basic earnings per share calculation	31,469,026	29,474,866	31,077,910	29,047,998
Common shares used in diluted earnings per share calculation	31,625,635	29,624,311	31,235,049	29,167,681
Dividends declared per common share	$0.53	$0.45	$1.49	$1.35

Consolidated_Statements_of_Ope1

Consolidated Statements of Operations (Parenthetical) (USD $)	2 Months Ended	3 Months Ended	9 Months Ended
In Thousands, unless otherwise specified	Aug. 31, 2012	Sep. 30, 2012	Sep. 30, 2012
Income Statement [Abstract]	'	'	'
Gain on disposal from discontinued operations	$4,500	$4,498	$4,498

Consolidated_Statements_of_Com

Consolidated Statements of Comprehensive Income (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Statement Of Income And Comprehensive Income [Abstract]	'	'	'	'
Net income	$19,799	$18,958	$52,223	$42,087
Other comprehensive income:	'	'	'	'
Change in fair value of derivatives net of reclassification to interest expense	-3,572	-1,742	5,189	-5,969
Total comprehensive income	16,227	17,216	57,412	36,118
Comprehensive income attributable to noncontrolling interest	-102	-137	-364	-361
Comprehensive income attributable to common shareholders	$16,125	$17,079	$57,048	$35,757

Consolidated_Statements_of_Cas

Consolidated Statements of Cash Flows (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012
Operating Activities	'	'
Net income	$52,223	$42,087
Adjustments to reconcile net income to net cash provided by operating activities:	'	'
Depreciation and amortization	34,118	31,247
Amortization of deferred financing fees	640	627
Gain on sale of storage facilities	'	-4,498
Gain on sale of real estate	-421	'
Equity in income of joint ventures	-1,417	-608
Distributions from unconsolidated joint venture	1,898	1,471
Non-vested stock earned	2,067	1,906
Stock option expense	261	238
Changes in assets and liabilities (excluding the effects of acquisitions):	'	'
Accounts receivable	-122	-308
Prepaid expenses	-481	-1,025
Receipts from (advances to) joint ventures	74	-62
Accounts payable and other liabilities	-3,531	-2,242
Deferred revenue	304	-413
Net cash provided by operating activities	85,613	68,420
Investing Activities	'	'
Acquisitions of storage facilities	-50,193	-105,137
Improvements, equipment additions, and construction in progress	-18,979	-20,813
Net proceeds from the sale of real estate	4,367	47,698
Investment in unconsolidated joint ventures	-4,111	-3,482
Reimbursement of property deposits	99	365
Net cash used in investing activities	-68,817	-81,369
Financing Activities	'	'
Net proceeds from sale of common stock	91,103	78,314
Proceeds from line of credit	120,000	70,000
Repayments of line of credit	-176,000	-90,000
Proceeds from term notes	325,000	'
Repayments of term notes	-325,000	'
Financing costs	-1,554	'
Dividends paid-common stock	-46,326	-39,317
Distributions to noncontrolling interest holders	-297	-458
Redemption of operating partnership units	-306	-7,364
Mortgage principal payments	-1,009	-128
Net cash (used in) provided by financing activities	-14,389	11,047
Net increase in cash	2,407	-1,902
Cash at beginning of period	7,255	7,321
Cash at end of period	9,662	5,419
Supplemental cash flow information	'	'
Cash paid for interest, net of interest capitalized	$24,876	$24,808

Basis_of_Presentation

Basis of Presentation	9 Months Ended
	Sep. 30, 2013
Accounting Policies [Abstract]	'
Basis of Presentation	'
	1	BASIS OF PRESENTATION
	The accompanying unaudited financial statements of Sovran Self Storage, Inc. have been prepared in accordance with generally accepted accounting principles for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all information and footnotes required by generally accepted accounting principles for complete financial statements. In the opinion of management, all adjustments (consisting of normal recurring accruals) considered necessary for a fair presentation have been included. Operating results for the nine-month period ended September 30, 2013 are not necessarily indicative of the results that may be expected for the year ending December 31, 2013.

Organization

Organization	9 Months Ended
	Sep. 30, 2013
Accounting Policies [Abstract]	'
Organization	'
	2	ORGANIZATION
	Sovran Self Storage, Inc. (the “Company,” “We,” “Our,” or “Sovran”), a self-administered and self-managed real estate investment trust (a “REIT”), was formed on April 19, 1995 to own and operate self-storage facilities throughout the United States. On June 26, 1995, the Company commenced operations effective with the completion of its initial public offering. At September 30, 2013, we had an ownership interest in and/or managed 471 self-storage properties in 25 states under the name Uncle Bob’s Self Storage ®. Among our 471 self-storage properties are 25 properties that we manage for an unconsolidated joint venture (Sovran HHF Storage Holdings LLC) of which we are a 20% owner, 30 properties that we manage for an unconsolidated joint venture (Sovran HHF Storage Holdings II LLC) of which we are a 15% owner, and 20 properties that we manage and in which have no ownership interest. Approximately 40% of the Company’s revenue is derived from stores in the states of Texas and Florida.
	All of the Company’s assets are owned by, and all its operations are conducted through, Sovran Acquisition Limited Partnership (the “Operating Partnership”). Sovran Holdings, Inc., a wholly-owned subsidiary of the Company (the “Subsidiary”), is the sole general partner of the Operating Partnership; the Company is a limited partner of the Operating Partnership, and through its ownership of the Subsidiary and its limited partnership interest controls the operations of the Operating Partnership, holding a 99.4% ownership interest therein as of September 30, 2013. The remaining ownership interests in the Operating Partnership (the “Units”) are held by certain former owners of assets acquired by the Operating Partnership subsequent to its formation.
	We consolidate all wholly owned subsidiaries. Partially owned subsidiaries and joint ventures are consolidated when we control the entity. Our consolidated financial statements include the accounts of the Company, the Operating Partnership, Locke Sovran I LLC (a wholly-owned subsidiary), Locke Sovran II LLC (a wholly-owned subsidiary), and Uncle Bob’s Management, LLC (the Company’s taxable REIT subsidiary). All intercompany transactions and balances have been eliminated. Investments in joint ventures that we do not control but for which we have significant influence over are reported using the equity method.
	On June 30, 2011, the Company entered into a newly formed joint venture agreement with an owner of a self-storage facility in New Jersey (West Deptford JV LLC). As part of the agreement the Company contributed $4.2 million to the joint venture for a $2.8 million mortgage note at 8%, a 20% common interest, and a $1.4 million preferred interest with an 8% preferred return. The Company had concluded that this joint venture is a variable interest entity pursuant to the guidance in FASB ASC Topic 810, “Consolidation” on the basis that the total equity investment in the joint venture is not sufficient to permit the joint venture to finance its activities without additional subordinated financial support from its investors. On February 5, 2013 the Company entered into a Membership Interest Purchase Agreement to sell its common and preferred interests in West Deptford JV LLC to the other joint venture partner for approximately $1.4 million, resulting in a gain of $0.4 million. Simultaneous with this transaction the joint venture partner also repaid the $2.8 million mortgage note held by the Company. As a result of these transactions the Company no longer holds any ownership interest in this joint venture.
	Included in the consolidated balance sheets are noncontrolling redeemable operating partnership units. These interests are presented in the “mezzanine” section of the consolidated balance sheet because they do not meet the functional definition of a liability or equity under current accounting literature. These represent the outside ownership interests of the limited partners in the Operating Partnership. At September 30, 2013, there were 199,163 noncontrolling redeemable operating partnership Units outstanding (204,028 at December 31, 2012). The Operating Partnership is obligated to redeem each of these limited partnership Units in the Operating Partnership at the request of the holder thereof for cash equal to the fair market value of a share of the Company’s common stock, at the time of such redemption, provided that the Company at its option may elect to acquire any such Unit presented for redemption for one common share or cash. The Company accounts for these noncontrolling redeemable Operating Partnership Units under the provisions of EITF D-98, “Classification and Measurement of Redeemable Securities” which are included in FASB ASC Topic 480-10-S99. The application of the FASB ASC Topic 480-10-S99 accounting model requires the noncontrolling interest to follow normal noncontrolling interest accounting and then be marked to redemption value at the end of each reporting period if higher (but never adjusted below that normal noncontrolling interest accounting amount). The offset to the adjustment to the carrying amount of the noncontrolling redeemable Operating Partnership Units is reflected in dividends in excess of net income. Accordingly, in the accompanying consolidated balance sheet, noncontrolling redeemable Operating Partnership Units are reflected at redemption value at September 30, 2013 and December 31, 2012, equal to the number of Units outstanding multiplied by the fair market value of the Company’s common stock at that date. Redemption value exceeded the value determined under the Company’s historical basis of accounting at those dates.
	(Dollars in thousands)		Nine Months
			Ended
			Sep. 30, 2013
	Beginning balance noncontrolling redeemable Operating Partnership Units		$	12,670
	Redemption of Operating Partnership Units			(306	)
	Redemption value in excess of carrying value for Units redeemed			4
	Net income attributable to noncontrolling interests			331
	Distributions			(297	)
	Adjustment to redemption value			2,514
	Ending balance noncontrolling redeemable Operating Partnership Units		$	14,916

Stock_Based_Compensation

Stock Based Compensation	9 Months Ended
	Sep. 30, 2013
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]	'
Stock Based Compensation	'
	3	STOCK BASED COMPENSATION
	The Company accounts for stock-based compensation under the provisions of ASC Topic 718, “Compensation - Stock Compensation”. The Company recognizes compensation cost in its financial statements for all share based payments granted, modified, or settled during the period. For awards with graded vesting, compensation cost is recognized on a straight-line basis over the related vesting period.
	For the three months ended September 30, 2013 and 2012, the Company recorded compensation expense (included in general and administrative expense) of $43,000 and $59,000, respectively, related to stock options and $795,000 and $597,000, respectively, related to amortization of non-vested stock grants. For the nine months ended September 30, 2013 and 2012, the Company recorded compensation expense (included in general and administrative expense) of $261,000 and $238,000, respectively, related to stock options and $1,977,000 and $1,794,000, respectively, related to amortization of non-vested stock grants.
	During the three months ended September 30, 2013 and 2012, employees exercised 23,835 and 31,435 stock options respectively, and 13,334 and 13,334 shares of non-vested stock, respectively, vested. During the nine months ended September 30, 2013 and 2012, employees exercised 121,845 and 77,620 stock options respectively, and 32,796 and 49,807 shares of non-vested stock, respectively, vested.

Investment_in_Storage_Faciliti

Investment in Storage Facilities	9 Months Ended
	Sep. 30, 2013
Real Estate [Abstract]	'
Investment in Storage Facilities	'
	4	INVESTMENT IN STORAGE FACILITIES
	The following summarizes our activity in storage facilities during the nine months ended September 30, 2013.
	(dollars in thousands)
	Cost:
	Beginning balance		$	1,755,954
	Acquisition of storage facilities			49,466
	Improvements and equipment additions			14,929
	Net increase in construction in progress			4,559
	Dispositions and impairments			(4,797	)
	Ending balance		$	1,820,111
	Accumulated Depreciation:
	Beginning balance		$	328,952
	Depreciation expense during the period			31,436
	Dispositions			(327	)
	Ending balance		$	360,061
	The assets and liabilities of the acquired storage facilities, which primarily consist of tangible and intangible assets, are measured at fair value on the date of acquisition in accordance with the principles of FASB ASC Topic 820, “Fair Value Measurements and Disclosures.” During the nine months ended September 30, 2013, the Company acquired six self-storage facilities to expand its presence in existing markets and the purchase price of the facilities has preliminarily been assigned as follows:
	(dollars in thousands)										Consideration paid							Acquisition Date Fair Value
	State		Number of			Date of			Purchase		Cash Paid		Loan		Net Other			Land		Building,		In-Place		Closing
			Properties			Acquisition			Price				Assumed		Liabilities					Equipment, and		Customers		Costs
															(Assets)					Improvements		Leases		Expensed
															Assumed
	2013
	Texas			1			2/11/13		$	2,400	$	2,382	$	—	$	18		$	337	$	2,005	$	58	$	145
	New York			1			3/22/13			11,050		11,119		—		(69	)		2,122		8,736		192		264
	Massachusetts			1			3/22/13			8,850		8,848		—		2			1,553		7,186		111		161
	New York			2			8/29/13			22,000		21,985		—		15			3,320		18,378		302		506
	Colorado			1			9/30/13			5,940		5,859		—		81			628		5,201		111		187
	Total 2013			6					$	50,240	$	50,193	$	—	$	47		$	7,960	$	41,506	$	774	$	1,263
	The Company measures the fair value of in-place customer lease intangible assets based on the Company’s experience with customer turnover. The Company amortizes in-place customer leases on a straight-line basis over 12 months (the estimated future benefit period). In-place customer leases are included in other assets on the Company’s balance sheet as follows:
			Sep. 30,			Dec. 31,
	(Dollars in thousands)		2013			2012
	In-place customer leases		$	13,893		$	13,228
	Accumulated amortization			(12,910	)		(10,337	)
	Net carrying value at the end of period		$	983		$	2,891
	Amortization expense related to in-place customer leases was $2.7 million and $2.8 million for the nine months ended September 30, 2013 and 2012, respectively. The Company expects to record $3.3 million of amortization expense for the year ended December 31, 2013.

Discontinued_Operations

Discontinued Operations	9 Months Ended
	Sep. 30, 2013
Discontinued Operations And Disposal Groups [Abstract]	'
Discontinued Operations	'
	5	DISCONTINUED OPERATIONS
	In July and August of 2012, the Company sold 17 non-strategic storage facilities in Maryland (1), Michigan (4), and Texas (12) for net proceeds of approximately $47.7 million resulting in a gain of approximately $4.5 million. The operations of these facilities are reported as discontinued operations in 2012. Cash flows of discontinued operations have not been segregated from the cash flows of continuing operations on the accompanying consolidated statement of cash flows for the nine months ended September 30, 2012. The following is a summary of the amounts reported as discontinued operations:
	(dollars in thousands)		Jan. 1, 2013		Jan. 1, 2012
			to		to
			Sep. 30, 2013		Sep. 30, 2012
	Total revenue		$	—	$	5,144
	Property operations and maintenance expense			—		(1,601	)
	Real estate tax expense			—		(561	)
	Depreciation and amortization expense			—		(787	)
	Net realized gain on sale of property			—		4,498
	Total income from discontinued operations		$	—	$	6,693

Unsecured_Line_of_Credit_and_T

Unsecured Line of Credit and Term Notes	9 Months Ended
	Sep. 30, 2013
Debt Disclosure [Abstract]	'
Unsecured Line of Credit and Term Notes	'
	6	UNSECURED LINE OF CREDIT AND TERM NOTES
	Borrowings outstanding on our unsecured line of credit and term notes are as follows:
			Sep. 30,		Dec. 31,
	(Dollars in thousands)		2013		2012
	Revolving line of credit borrowings		$	49,000	$	105,000
	Term note due September 4, 2013			—		20,000
	Term note due September 4, 2013			—		80,000
	Term note due April 13, 2016			150,000		150,000
	Term note due August 3, 2018			—		225,000
	Term note due June 4, 2020			225,000		—
	Term note due June 4, 2020			100,000		—
	Term note due August 5, 2021			100,000		100,000
	Total term notes payable		$	575,000	$	575,000
	On June 4, 2013, the Company entered into an amendment to its unsecured credit arrangements. As part of the amended agreement, the Company entered into a $225 million unsecured term note maturing June 4, 2020 bearing interest at LIBOR plus a margin based on the Company’s credit rating (at September 30, 2013 the margin is 1.65%). The agreement also provides for a $175 million (expandable to $250 million) revolving line of credit bearing interest at a variable rate equal to LIBOR plus a margin based on the Company’s credit rating (at September 30, 2013 the margin is 1.50%), and requires a 0.20% facility fee. The interest rate at September 30, 2013 on the Company’s available line of credit was approximately 1.68% (2.21% at December 31, 2012). At September 30, 2013, there was $126 million available on the unsecured line of credit without considering the additional availability under the expansion feature. The revolving line of credit has a maturity date of June 4, 2018, but can be extended for two one-year periods at the Company’s option with the payment of an extension fee equal to 0.125% of the total line of credit commitment.
	In addition, on June 4, 2013, as part of the amendment to its unsecured credit arrangement, the Company secured an additional $100 million term note with a delayed draw feature that was used to fund the Company’s term notes that matured in September 2013. The delayed draw term note matures June 4, 2020 and bears interest at LIBOR plus a margin based on the Company’s credit rating (at September 30, 2013 the margin is 1.65%).
	In connection with the execution of the amendment to our unsecured credit agreement, it was determined that the borrowing capacity of each lender participating in the revolving line of credit exceeded their borrowing capacities prior to the amendment. As a result, unamortized deferred financing costs associated with the agreement prior to its amendment remain deferred and are being amortized to interest expense over the term of the newly amended agreement. Fees and other costs paid to execute the amendment relating to the revolving line of credit totaling $0.5 million were recorded as additional deferred financing costs and are being amortized to interest expense over the term of the newly amended agreement.
	The Company paid $1.1 million in fees to lenders for their commitments under the unsecured term note portion of the newly amended agreement. These lenders’ commitments were determined to be a modification of their unsecured term note commitments prior to the amendment. Such costs were recorded as additional deferred financing costs and are being amortized to interest expense over the term of the newly amended agreement. In addition, previously unamortized deferred financing costs associated with the unsecured term note commitments prior to the amendment remain deferred and are being amortized to interest expense over the term of the newly amended agreement.
	The line of credit and term notes require the Company to meet certain financial covenants, measured on a quarterly basis, including prescribed leverage, fixed charge coverage, minimum net worth, limitations on additional indebtedness and limitations on dividend payouts. At September 30, 2013, the Company was in compliance with its debt covenants.
	We believe that if operating results remain consistent with historical levels and levels of other debt and liabilities remain consistent with amounts outstanding at September 30, 2013 the entire availability on the line of credit could be drawn without violating our debt covenants.
	The Company’s fixed rate term notes contain a provision that allows for the noteholders to call the debt upon a change of control of the Company at an amount that includes a make whole premium based on rates in effect on the date of the change of control.

Mortgages_Payable_and_Debt_Mat

Mortgages Payable and Debt Maturities	9 Months Ended
	Sep. 30, 2013
Debt Disclosure [Abstract]	'
Mortgages Payable and Debt Maturities	'
	7	MORTGAGES PAYABLE AND DEBT MATURITIES
	Mortgages payable at September 30, 2013 and December 31, 2012 consist of the following:
	(dollars in thousands)		September 30,		December 31,
			2013		2012
	6.76% mortgage note due September 11, 2013, secured by one self-storage facility, repaid September 11, 2013			—		896
	6.35% mortgage note due March 11, 2014, secured by one self-storage facility with an aggregate net book value of $3.4 million, principal and interest paid monthly (effective interest rate 6.45%)			958		983
	5.99% mortgage notes due May 1, 2026, secured by one self-storage facility with an aggregate net book value of $4.4 million, principal and interest paid monthly (effective interest rate 6.20%)			2,284		2,372
	Total mortgages payable		$	3,242	$	4,251
	The table below summarizes the Company’s debt obligations and interest rate derivatives at September 30, 2013. The estimated fair value of financial instruments is subjective in nature and is dependent on a number of important assumptions, including discount rates and relevant comparable market information associated with each financial instrument. The fair value of the fixed rate term notes and mortgage notes were estimated by discounting the future cash flows using the current rates at which similar loans would be made to borrowers with similar credit ratings and for the same remaining maturities. These assumptions are considered Level 2 inputs within the fair value hierarchy as described in Note 9. The carrying values of our variable rate debt instruments approximate their fair values as these debt instruments bear interest at current market rates that approximate market participant rates. This is considered a Level 2 input within the fair value hierarchy. The use of different market assumptions and estimation methodologies may have a material effect on the reported estimated fair value amounts. Accordingly, the estimates presented below are not necessarily indicative of the amounts the Company would realize in a current market exchange.
			Expected Maturity Date Including Discount
	(dollars in thousands)		2013		2014		2015		2016		2017		Thereafter		Total		Fair
																	Value
	Line of credit - variable rate LIBOR + 1.50% (1.68% at September 30, 2013)			—		—		—		—		—	$	49,000	$	49,000	$	49,000
	Notes Payable:
	Term note - fixed rate 6.38%			—		—		—	$	150,000		—		—	$	150,000	$	169,366
	Term note - variable rate LIBOR+1.65% (1.83% at September 30, 2013)			—		—		—		—		—	$	225,000	$	225,000	$	225,000
	Term note - variable rate LIBOR+1.65% (1.83% at September 30, 2013)			—		—		—		—		—	$	100,000	$	100,000	$	100,000
	Term note - fixed rate 5.54%			—		—		—		—		—	$	100,000	$	100,000	$	113,978
	Mortgage note - fixed rate 6.35%		$	9	$	949		—		—		—		—	$	958	$	978
	Mortgage notes - fixed rate 5.99%		$	30	$	126	$	134	$	142	$	151	$	1,701	$	2,284	$	2,396
	Interest rate derivatives – asset			—		—		—		—		—		—		—	($	166	)
	Interest rate derivatives – liability			—		—		—		—		—		—		—	$	10,524

Derivative_Financial_Instrumen

Derivative Financial Instruments	9 Months Ended
	Sep. 30, 2013
Derivative Instruments And Hedging Activities Disclosure [Abstract]	'
Derivative Financial Instruments	'
	8	DERIVATIVE FINANCIAL INSTRUMENTS
	Interest rate swaps are used to adjust the proportion of total debt that is subject to variable interest rates. The interest rate swaps require the Company to pay an amount equal to a specific fixed rate of interest times a notional principal amount and to receive in return an amount equal to a variable rate of interest times the same notional amount. The notional amounts are not exchanged. No other cash payments are made unless the contract is terminated prior to its maturity, in which case the contract would likely be settled for an amount equal to its fair value. The Company enters interest rate swaps with a number of major financial institutions to minimize counterparty credit risk.
	The interest rate swaps qualify and are designated as hedges of the amount of future cash flows related to interest payments on variable rate debt. Therefore, the interest rate swaps are recorded in the consolidated balance sheet at fair value and the related gains or losses are deferred in shareholders’ equity as Accumulated Other Comprehensive Loss (“AOCL”). These deferred gains and losses are recognized in interest expense during the period or periods in which the related interest payments affect earnings. However, to the extent that the interest rate swaps are not perfectly effective in offsetting the change in value of the interest payments being hedged, the ineffective portion of these contracts is recognized in earnings immediately. Ineffectiveness was deminimus in the nine months ended September 30, 2013 and 2012.
	The Company has interest rate swap agreements in effect at September 30, 2013 as detailed below to effectively convert a total of $325 million of variable-rate debt to fixed-rate debt.
	Notional Amount		Effective			Expiration			Fixed Rate			Floating
			Date			Date			Paid			Rate Received
	$125 Million			9/1/11			8/1/18			2.37	%		1 month LIBOR
	$100 Million			12/30/11			12/29/17			1.6125	%		1 month LIBOR
	$100 Million			9/4/13			9/4/18			1.371	%		1 month LIBOR
	$100 Million			12/29/17			11/29/19			3.968	%		1 month LIBOR
	$125 Million			8/1/18			6/1/20			4.193	%		1 month LIBOR
	The interest rate swap agreements are the only derivative instruments, as defined by FASB ASC Topic 815 “Derivatives and Hedging”, held by the Company. During the nine months ended September 30, 2013, and 2012, the net reclassification from AOCL to interest expense was $4.0 million and $3.7 million, respectively, based on payments made under the swap agreements. Based on current interest rates, the Company estimates that payments under the interest rate swaps will be approximately $5.4 million for the twelve months ended September 30, 2014. Payments made under the interest rate swap agreements will be reclassified to interest expense as settlements occur. The fair value of the swap agreements, including accrued interest, were an asset of $0.2 million and a liability of $10.5 million at September 30, 2013, and a liability of $15.7 million at December 31, 2012.
	The changes in AOCL for the three and nine months ended September 30, 2013 and September 30, 2012 are summarized as follows:
	(dollars in thousands)		Jul. 1, 2013			Jul. 1, 2012			Jan. 1, 2013			Jan. 1, 2012
			to			to			to			to
			Sep. 30, 2013			Sep. 30, 2012			Sep. 30, 2013			Sep. 30, 2012
	Accumulated other comprehensive loss beginning of period		$	(6,481	)	$	(14,482	)	$	(15,242	)	$	(10,255	)
	Realized loss reclassified from accumulated other comprehensive loss to interest expense			1,474			1,425			3,979			3,707
	Unrealized gain (loss) from changes in the fair value of the effective portion of the interest rate swaps			(5,046	)		(3,167	)		1,210			(9,676	)
	Gain (loss) included in other comprehensive loss			(3,572	)		(1,742	)		5,189			(5,969	)
	Accumulated other comprehensive loss end of period		$	(10,053	)	$	(16,224	)	$	(10,053	)	$	(16,224	)

Fair_Value_Measurements

Fair Value Measurements

9 Months Ended

Sep. 30, 2013

Fair Value Disclosures [Abstract]

'

Fair Value Measurements

'

9

FAIR VALUE MEASUREMENTS

The Company applies the provisions of ASC Topic 820 “Fair Value Measurements and Disclosures” in determining the fair value of its financial and nonfinancial assets and liabilities. ASC Topic 820 establishes a valuation hierarchy for disclosure of the inputs to valuation used to measure fair value. This hierarchy prioritizes the inputs into three broad levels as follows. Level 1 inputs are quoted prices (unadjusted) in active markets for identical assets or liabilities. Level 2 inputs are quoted prices for similar assets and liabilities in active markets or inputs that are observable for the asset or liability, either directly or indirectly through market corroboration. Level 3 inputs are unobservable inputs based on our own assumptions used to measure assets and liabilities at fair value. A financial asset or liability’s classification within the hierarchy is determined based on the lowest level input that is significant to the fair value measurement.

In May 2011 the FASB issued ASU No. 2011-04, Fair Value Measurements (Topic 820): Amendments to Achieve Common Fair Value Measurement and Disclosure Requirements in US GAAP and International Financial Reporting Standards (“IFRS”) (“ASU 2011-04”). ASU 2011-04 represents the converged guidance of the FASB and the IASB (the “Boards”) on fair value measurements. The collective efforts of the Boards and their staffs, reflected in ASU 2011-04, have resulted in common requirements for measuring fair value and for disclosing information about fair value measurements, including a consistent meaning of the term “fair value.” The Boards have concluded the common requirements will result in greater comparability of fair value measurements presented and disclosed in financial statements prepared in accordance with GAAP and IFRS. The amendments in this ASU were required to be applied prospectively, and were effective for interim and annual periods beginning after December 15, 2011. The Company adopted the provisions of ASU 2011-04 on January 1, 2012 and its adoption did not have a significant impact on the Company’s current fair value measurements or disclosures. The adoption is not expected to have a significant effect on any future fair value measurements or disclosures.

Refer to Note 7 for presentation of the fair values of debt obligations which are disclosed at fair value on a recurring basis.

The following table provides the assets and liabilities carried at fair value measured on a recurring basis as of September 30, 2013 (in thousands):

Asset (Liability)

Level 1

Level 2

Level 3

Interest rate swaps

166

—

166

—

Interest rate swaps

(10,524

)

—

(10,524

)

—

Interest rate swaps are over the counter securities with no quoted readily available Level 1 inputs, and therefore are measured at fair value using inputs that are directly observable in active markets and are classified within Level 2 of the valuation hierarchy, using the income approach.

During 2013, assets and liabilities measured at fair value on a non-recurring basis included the assets acquired and liabilities assumed in connection with the acquisition of six storage facilities (see note 4). To determine the fair value of land, the Company used prices per acre derived from observed transactions involving comparable land in similar locations, which is considered a Level 2 input. To determine the fair value of buildings, equipment and improvements, the Company used current replacement cost based on information derived from construction industry data by geographic region as adjusted for the age, condition, and economic obsolescence associated with these assets, which are considered Level 2 and 3 inputs. The fair value of in-place customer leases is 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, which is a Level 3 input. Other assets acquired and liabilities assumed in the acquisitions consist primarily of prepaid or accrued real estate taxes and deferred revenues from advance monthly rentals paid by customers. The fair values of these assets and liabilities are based on their carrying values as they typically turn over within one year from the acquisition date and these are Level 3 inputs.

Investment_in_Joint_Ventures

Investment in Joint Ventures	9 Months Ended
	Sep. 30, 2013
Equity Method Investments And Joint Ventures [Abstract]	'
Investment in Joint Ventures	'
	10	INVESTMENT IN JOINT VENTURES
	The Company has a 20% ownership interest in Sovran HHF Storage Holdings LLC (“Sovran HHF”), a joint venture that was formed in May 2008 to acquire self-storage properties that are managed by the Company. The carrying value of the Company’s investment at September 30, 2013 was $24.7 million. Twenty-five properties were acquired by Sovran HHF in 2008 for approximately $171.5 million and no additional properties have been acquired by Sovran HHF since then. In 2008, the Company contributed $18.6 million to the joint venture as its share of capital required to fund the acquisitions. In 2013, 2012 and 2011 the Company contributed an additional $3.9 million, $1.2 million and $0.8 million, respectively, to the joint venture. As of September 30, 2013, the carrying value of the Company’s investment in Sovran HHF exceeds its share of the underlying equity in net assets of Sovran HHF by approximately $1.7 million as a result of the capitalization of certain acquisition related costs in 2008. This difference is included in the carrying value of the investment, which is assessed for other-than-temporary impairment on a periodic basis. No other-than-temporary impairments have been recorded on this investment.
	The Company has a 15% ownership interest in Sovran HHF Storage Holdings II LLC (“Sovran HHF II”), a joint venture that was formed in 2011 to acquire self-storage properties that are managed by the Company. The carrying value of the Company’s investment at September 30, 2013 was $13.1 million. Twenty properties were acquired by Sovran HHF II during 2011 for approximately $166.1 million. During 2011, the Company contributed $12.8 million to the joint venture as its share of capital required to fund the acquisitions. Ten additional properties were acquired by Sovran HHF II during 2012 for approximately $29 million. During 2013 and 2012, the Company contributed $0.2 million and $2.4 million, respectively, to the joint venture as its share of capital required to fund the acquisitions and capital expenditures. The carrying value of this investment is assessed for other-than-temporary impairment on a periodic basis and no such impairments have been recorded on this investment.
	As manager of Sovran HHF and Sovran HHF II, the Company earns a management and call center fee of 7% of gross revenues which totaled $0.9 million and $0.8 million for the three months ended September 30, 2013 and 2012, respectively. The management and call center fees earned by the Company for the nine months ended September 30, 2013 and 2012 totaled $2.5 million and $2.2 million, respectively. For the nine months ended September 30, 2012 the Company also received acquisition fees of $0.2 million for securing purchases for Sovran HHF II in 2012. No acquisition fee was earned in 2013.
	The Company’s share of Sovran HHF and Sovran HHF II’s income for the three months ended September 30, 2013 and 2012 was $0.6 million and $0.3 million, respectively. The Company’s share of Sovran HHF and Sovran HHF II’s income for the nine months ended September 30, 2013 and 2012 was $1.4 million and $0.6 million, respectively.
	The Company also has a 49% ownership interest in Iskalo Office Holdings, LLC, which owns the building that houses the Company’s headquarters and other tenants. The Company’s investment includes a capital contribution of $0.2 million. The carrying value of the Company’s investment is a liability of $0.5 million at September 30, 2013 and December 31, 2012, and is included in accounts payable and accrued liabilities in the accompanying consolidated balance sheets. The Company’s share of Iskalo Office Holdings, LLC’s income (loss) for the three months ended September 30, 2013 and 2012 was 23,000 and ($4,000), respectively. The Company’s share of Iskalo Office Holdings, LLC’s income for the nine months ended September 30, 2013 and 2012 was $44,000 and $9,000, respectively.
	A summary of the unconsolidated joint ventures’ financial statements as of and for the nine months ended September 30, 2013 is as follows:
	(dollars in thousands)		Sovran HHF			Sovran HHF			Iskalo Office
			Storage			Storage			Holdings, LLC
			Holdings LLC			Holdings II LLC
	Balance Sheet Data:
	Investment in storage facilities, net		$	158,622		$	188,635		$	—
	Investment in office building			—			—			4,968
	Other assets			5,294			5,190			909
	Total Assets		$	163,916		$	193,825		$	5,877
	Due to the Company		$	428		$	358		$	—
	Mortgages payable			45,341			103,776			6,474
	Other liabilities			3,118			2,329			933
	Total Liabilities			48,887			106,463			7,407
	Unaffiliated partners’ equity (deficiency)			92,023			74,263			(1,053	)
	Company equity (deficiency)			23,006			13,099			(477	)
	Total Partners’ Equity (Deficiency)			115,029			87,362			(1,530	)
	Total Liabilities and Partners’ Equity (Deficiency)		$	163,916		$	193,825		$	5,877
	Income Statement Data:
	Total revenues		$	15,766		$	20,007		$	954
	Property operating expenses			(5,108	)		(7,021	)		(383	)
	Administrative, management and call center fees			(1,191	)		(1,490	)		—
	Depreciation and amortization of customer list			(2,841	)		(3,120	)		(170	)
	Amortization of financing fees			(84	)		(152	)		(9	)
	Income tax expense			(53	)		(212	)		—
	Interest expense			(2,710	)		(3,895	)		(303	)
	Net income		$	3,779		$	4,117		$	89
	The Company does not guarantee the debt of Sovran HHF, Sovran HHF II, or Iskalo Office Holdings, LLC.
	We do not expect to have material future cash outlays relating to these joint ventures.

Income_Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2013
Income Tax Disclosure [Abstract]	'
Income Taxes	'
	11	INCOME TAXES
	The Company qualifies as a REIT under the Internal Revenue Code of 1986, as amended, and will generally not be subject to corporate income taxes to the extent it distributes its taxable income to its shareholders and complies with certain other requirements.
	The Company has elected to treat its Uncle Bob’s Management, LLC subsidiary as a taxable REIT subsidiary. In general, the Company’s taxable REIT subsidiary may perform additional services for tenants and generally may engage in certain real estate or non-real estate related business. A taxable REIT subsidiary is subject to corporate federal and state income taxes. Deferred tax assets and liabilities are determined based on differences between financial reporting and tax bases of assets and liabilities.
	For the three months ended September 30, 2013 and 2012, the Company recorded federal and state income tax expense of $0.3 million and $0.6 million, respectively, which are included in general and administrative expense in the consolidated statements of operations. For the nine months ended September 30, 2013 and 2012, the Company recorded federal and state income tax expense of $1.0 million and $1.6 million, respectively, which are included in general and administrative expense in the consolidated statements of operations. At September 30, 2013 and 2012, there were no material unrecognized tax benefits. Interest and penalties relating to uncertain tax positions will be recognized in income tax expense when incurred. As of September 30, 2013, the Company had no interest or penalties related to uncertain tax positions. The Company’s taxable REIT subsidiary has a deferred tax liability of $1.0 million as of September 30, 2013, which is included in accounts payable and accrued liabilities in the consolidated balance sheet. The tax years 2010-2012 remain open to examination by the major taxing jurisdictions to which the Company is subject.

Earnings_Per_Share

Earnings Per Share	9 Months Ended
	Sep. 30, 2013
Earnings Per Share [Abstract]	'
Earnings Per Share	'
	12	EARNINGS PER SHARE
	The Company reports earnings per share data in accordance ASC Topic 260, “Earnings Per Share.” Effective January 1, 2009, FASB ASC Topic 260 was updated for the issuance of FASB Staff Position (“FSP”) EITF 03-6-1, “Determining Whether Instruments Granted in Share-Based Payment Transactions Are Participating Securities”, or FSP EITF 03-6-1, with transition guidance included in FASB ASC Topic 260-10-65-2. Under FSP EITF 03-6-1, unvested share-based payment awards that contain nonforfeitable rights to dividends or dividend equivalents, whether paid or unpaid, are participating securities and shall be included in the computation of earnings-per-share pursuant to the two-class method. The Company has calculated its basic and diluted earnings per share using the two-class method. The following table sets forth the computation of basic and diluted earnings per common share utilizing the two-class method.
	(in thousands except per share data)		Three Months		Three Months		Nine Months		Nine Months
			Ended		Ended		Ended		Ended
			Sep. 30, 2013		Sep. 30, 2012		Sep. 30, 2013		Sep. 30, 2012
	Numerator:
	Net income from continuing operations attributable to common shareholders		$	19,675	$	14,024	$	51,892	$	35,040
	Denominator:
	Denominator for basic earnings per share – weighted average shares			31,469		29,475		31,078		29,048
	Effect of Dilutive Securities:
	Stock options and non-vested stock			157		149		157		120
	Denominator for diluted earnings per share – adjusted weighted average shares and assumed conversion			31,626		29,624		31,235		29,168
	Basic earnings per common share from continuing operations attributable to common shareholders		$	0.63	$	0.48	$	1.67	$	1.2
	Basic earnings per common share attributable to common shareholders		$	0.63	$	0.64	$	1.67	$	1.43
	Diluted earnings per common share from continuing operations attributable to common shareholders		$	0.62	$	0.47	$	1.66	$	1.2
	Diluted earnings per common share attributable to common shareholders		$	0.62	$	0.63	$	1.66	$	1.43
	Not included in the effect of dilutive securities above are 121,916 unvested restricted shares for the three months ended September 30, 2013, and 9,500 stock options and 108,949 unvested restricted shares for the three months ended September 30, 2012, because their effect would be antidilutive. Not included in the effect of dilutive securities above are 2,667 stock options and 88,901 unvested restricted shares for the nine months ended September 30, 2013, and 41,833 stock options and 131,525 unvested restricted shares for the nine months ended September 30, 2012, because their effect would be antidilutive.

Shareholders_Equity

Shareholders' Equity	9 Months Ended
	Sep. 30, 2013
Equity [Abstract]	'
Shareholders' Equity	'
	13	SHAREHOLDERS’ EQUITY
	On February 27, 2013, the Company entered into a continuous equity offering program (“Equity Program”) with Wells Fargo Securities, LLC (“Wells Fargo”), Jefferies LLC fka Jefferies & Company, Inc. (“Jefferies”) and SunTrust Robinson Humphrey, Inc. (“SunTrust”), pursuant to which the Company may sell from time to time up to $175 million in aggregate offering price of shares of the Company’s common stock. Actual sales under the Equity Program will depend on a variety of factors and conditions, including, but not limited to, market conditions, the trading price of the Company’s common stock, and determinations of the appropriate sources of funding for the Company. The Company expects to continue to offer, sell, and issue shares of common stock under the Equity Program from time to time based on various factors and conditions, although the Company is under no obligation to sell any shares under the Equity Program.
	During the three months ended September 30, 2013, the Company issued 444,910 shares under this Equity Program at a weighted average issue price of $72.11 per share, generating net proceeds of $31.6 million after deducting $0.5 million of sales commissions payable to Jefferies. During the nine months ended September 30, 2013, the Company issued 1,266,910 shares under this Equity Program at a weighted average issue price of $65.58 per share, generating net proceeds of $81.9 million after deducting $0.5 million of sales commissions payable to SunTrust, $0.2 million to Wells Fargo, and $0.5 million to Jefferies. In addition to sales commissions, the Company incurred expenses of $0.1 million in connection with the Equity Program during 2013. The Company used the proceeds from the Equity Program to reduce the outstanding balance under the Company’s revolving line of credit and to fund the acquisition of six storage facilities. As of September 30, 2013, the Company had $91.9 million available for issuance under the Equity Program.

Recent_Accounting_Pronouncemen

Recent Accounting Pronouncements	9 Months Ended
	Sep. 30, 2013
Accounting Changes And Error Corrections [Abstract]	'
Recent Accounting Pronouncements	'
	14	RECENT ACCOUNTING PRONOUNCEMENTS
	In February 2013, the FASB issued Accounting Standards Update (“ASU”) 2013-02, Reporting of Amounts Reclassified Out of Accumulated Other Comprehensive Income, an amendment to FASB ASC Topic 220. The update requires disclosure of amounts reclassified out of accumulated other comprehensive income by component. In addition, an entity is required to present either on the face of the statement of operations or in the notes, significant amounts reclassified out of accumulated other comprehensive income by the respective line items of net income but only if the amount reclassified is required to be reclassified to net income in its entirety in the same reporting period. For amounts not reclassified in their entirety to net income, an entity is required to cross-reference to other disclosures that provide additional detail about those amounts. This ASU is effective prospectively for the Company’s fiscal years, and interim periods within those years beginning after December 15, 2012. The Company adopted ASU No. 2013-02 in 2013. The adoption of ASU No. 2013-02 did not have a material impact on the Company’s consolidated financial statements.

Commitment_and_Contingencies

Commitment and Contingencies	9 Months Ended
	Sep. 30, 2013
Commitments And Contingencies Disclosure [Abstract]	'
Commitment and Contingencies	'
	15	COMMITMENT AND CONTINGENCIES
	At September 30, 2013, the Company was under contract with a seller to acquire one self-storage facility for approximately $6.3 million. The purchase of this facility by the Company is subject to customary conditions to closing, and there is no assurance that this facility will be acquired.
	The Company conducts environmental investigations in connection with property acquisitions. At this time, the Company is not aware of any environmental contamination of any of its facilities that individually or in the aggregate would be material to the Company’s overall business, financial condition, or results of operations.

Subsequent_Events

Subsequent Events	9 Months Ended
	Sep. 30, 2013
Subsequent Events [Abstract]	'
Subsequent Events	'
	16	SUBSEQUENT EVENTS
	On October 2, 2013, the Company declared a quarterly dividend of $0.53 per common share. The dividend was paid on October 28, 2013 to shareholders of record on October 14, 2013. The total dividend paid amounted to $16.9 million.
	In October 2013, the Company sold one non-strategic storage facility in Ohio for net proceeds of approximately $3.2 million resulting in a gain of approximately $0.3 million.
	On November 1, 2013, the Company completed certain transactions with respect to the lease of four self storage facilities in New York and Connecticut with annual lease payments of $6 million with a provision for 4% annual increases, and an exclusive option to purchase the facilities for $120 million. The leases commence November 1, 2013 and run through December 31, 2028. The Company has an option to purchase the facilities during the period from February 2, 2015 through September 2, 2016.

Organization_Policies

Organization (Policies)	9 Months Ended
	Sep. 30, 2013
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]	'
Consolidation	'
	The Company had concluded that this joint venture is a variable interest entity pursuant to the guidance in FASB ASC Topic 810, “Consolidation” on the basis that the total equity investment in the joint venture is not sufficient to permit the joint venture to finance its activities without additional subordinated financial support from its investors.
Classification and Measurement of Redeemable Securities	'
	The Company accounts for these noncontrolling redeemable Operating Partnership Units under the provisions of EITF D-98, “Classification and Measurement of Redeemable Securities” which are included in FASB ASC Topic 480-10-S99. The application of the FASB ASC Topic 480-10-S99 accounting model requires the noncontrolling interest to follow normal noncontrolling interest accounting and then be marked to redemption value at the end of each reporting period if higher (but never adjusted below that normal noncontrolling interest accounting amount). The offset to the adjustment to the carrying amount of the noncontrolling redeemable Operating Partnership Units is reflected in dividends in excess of net income.
Stock-Based Compensation	'
	The Company accounts for stock-based compensation under the provisions of ASC Topic 718, “Compensation - Stock Compensation”. The Company recognizes compensation cost in its financial statements for all share based payments granted, modified, or settled during the period. For awards with graded vesting, compensation cost is recognized on a straight-line basis over the related vesting period.
Fair Value Measurements and Disclosures	'
	The assets and liabilities of the acquired storage facilities, which primarily consist of tangible and intangible assets, are measured at fair value on the date of acquisition in accordance with the principles of FASB ASC Topic 820, “Fair Value Measurements and Disclosures.”
Earnings Per Share	'
	The Company reports earnings per share data in accordance ASC Topic 260, “Earnings Per Share.” Effective January 1, 2009, FASB ASC Topic 260 was updated for the issuance of FASB Staff Position (“FSP”) EITF 03-6-1, “Determining Whether Instruments Granted in Share-Based Payment Transactions Are Participating Securities”, or FSP EITF 03-6-1, with transition guidance included in FASB ASC Topic 260-10-65-2. Under FSP EITF 03-6-1, unvested share-based payment awards that contain nonforfeitable rights to dividends or dividend equivalents, whether paid or unpaid, are participating securities and shall be included in the computation of earnings-per-share pursuant to the two-class method. The Company has calculated its basic and diluted earnings per share using the two-class method.
Amounts Reclassified Out of Accumulated Other Comprehensive Income	'
	In February 2013, the FASB issued Accounting Standards Update (“ASU”) 2013-02, Reporting of Amounts Reclassified Out of Accumulated Other Comprehensive Income, an amendment to FASB ASC Topic 220. The update requires disclosure of amounts reclassified out of accumulated other comprehensive income by component. In addition, an entity is required to present either on the face of the statement of operations or in the notes, significant amounts reclassified out of accumulated other comprehensive income by the respective line items of net income but only if the amount reclassified is required to be reclassified to net income in its entirety in the same reporting period. For amounts not reclassified in their entirety to net income, an entity is required to cross-reference to other disclosures that provide additional detail about those amounts. This ASU is effective prospectively for the Company’s fiscal years, and interim periods within those years beginning after December 15, 2012. The Company adopted ASU No. 2013-02 in 2013. The adoption of ASU No. 2013-02 did not have a material impact on the Company’s consolidated financial statements.

Organization_Tables

Organization (Tables)	9 Months Ended
	Sep. 30, 2013
Accounting Policies [Abstract]	'
Summary of Redeemable Noncontrolling Interest	'
	Redemption value exceeded the value determined under the Company’s historical basis of accounting at those dates.
	(Dollars in thousands)	Nine Months
		Ended
		Sep. 30, 2013
	Beginning balance noncontrolling redeemable Operating Partnership Units	$	12,670
	Redemption of Operating Partnership Units		(306	)
	Redemption value in excess of carrying value for Units redeemed		4
	Net income attributable to noncontrolling interests		331
	Distributions		(297	)
	Adjustment to redemption value		2,514
	Ending balance noncontrolling redeemable Operating Partnership Units	$	14,916

Investment_in_Storage_Faciliti1

Investment in Storage Facilities (Tables)	9 Months Ended
	Sep. 30, 2013
Real Estate [Abstract]	'
Summary of Activity in Storage Facilities	'
	The following summarizes our activity in storage facilities during the nine months ended September 30, 2013.
	(dollars in thousands)
	Cost:
	Beginning balance	$	1,755,954
	Acquisition of storage facilities		49,466
	Improvements and equipment additions		14,929
	Net increase in construction in progress		4,559
	Dispositions and impairments		(4,797	)
	Ending balance	$	1,820,111
	Accumulated Depreciation:
	Beginning balance	$	328,952
	Depreciation expense during the period		31,436
	Dispositions		(327	)
	Ending balance	$	360,061
Schedule of Acquired Facilities and Purchase Price of Facilities	'
	During the nine months ended September 30, 2013, the Company acquired six self-storage facilities to expand its presence in existing markets and the purchase price of the facilities has preliminarily been assigned as follows:
	(dollars in thousands)									Consideration paid							Acquisition Date Fair Value
	State	Number of			Date of			Purchase		Cash Paid		Loan		Net Other			Land		Building,		In-Place		Closing
		Properties			Acquisition			Price				Assumed		Liabilities					Equipment, and		Customers		Costs
														(Assets)					Improvements		Leases		Expensed
														Assumed
	2013
	Texas		1			2/11/13		$	2,400	$	2,382	$	—	$	18		$	337	$	2,005	$	58	$	145
	New York		1			3/22/13			11,050		11,119		—		(69	)		2,122		8,736		192		264
	Massachusetts		1			3/22/13			8,850		8,848		—		2			1,553		7,186		111		161
	New York		2			8/29/13			22,000		21,985		—		15			3,320		18,378		302		506
	Colorado		1			9/30/13			5,940		5,859		—		81			628		5,201		111		187
	Total 2013		6					$	50,240	$	50,193	$	—	$	47		$	7,960	$	41,506	$	774	$	1,263
Schedule of Fair Value of In-Place Customer Lease Intangible Assets	'
	In-place customer leases are included in other assets on the Company’s balance sheet as follows:
		Sep. 30,			Dec. 31,
	(Dollars in thousands)	2013			2012
	In-place customer leases	$	13,893		$	13,228
	Accumulated amortization		(12,910	)		(10,337	)
	Net carrying value at the end of period	$	983		$	2,891

Discontinued_Operations_Tables

Discontinued Operations (Tables)	9 Months Ended
	Sep. 30, 2013
Discontinued Operations And Disposal Groups [Abstract]	'
Summary of Amount Reported as Discontinued Operations	'
	for the nine months ended September 30, 2012. The following is a summary of the amounts reported as discontinued operations:
	(dollars in thousands)	Jan. 1, 2013		Jan. 1, 2012
		to		to
		Sep. 30, 2013		Sep. 30, 2012
	Total revenue	$	—	$	5,144
	Property operations and maintenance expense		—		(1,601	)
	Real estate tax expense		—		(561	)
	Depreciation and amortization expense		—		(787	)
	Net realized gain on sale of property		—		4,498
	Total income from discontinued operations	$	—	$	6,693

Unsecured_Line_of_Credit_and_T1

Unsecured Line of Credit and Term Notes (Tables)	9 Months Ended
	Sep. 30, 2013
Debt Disclosure [Abstract]	'
Borrowings Outstanding on Unsecured Line of Credit and Term Notes	'
	Borrowings outstanding on our unsecured line of credit and term notes are as follows:
		Sep. 30,		Dec. 31,
	(Dollars in thousands)	2013		2012
	Revolving line of credit borrowings	$	49,000	$	105,000
	Term note due September 4, 2013		—		20,000
	Term note due September 4, 2013		—		80,000
	Term note due April 13, 2016		150,000		150,000
	Term note due August 3, 2018		—		225,000
	Term note due June 4, 2020		225,000		—
	Term note due June 4, 2020		100,000		—
	Term note due August 5, 2021		100,000		100,000
	Total term notes payable	$	575,000	$	575,000

Mortgages_Payable_and_Debt_Mat1

Mortgages Payable and Debt Maturities (Tables)	9 Months Ended
	Sep. 30, 2013
Debt Disclosure [Abstract]	'
Summary of Mortgage Payable	'
	Mortgages payable at September 30, 2013 and December 31, 2012 consist of the following:
	(dollars in thousands)	September 30,		December 31,
		2013		2012
	6.76% mortgage note due September 11, 2013, secured by one self-storage facility, repaid September 11, 2013		—		896
	6.35% mortgage note due March 11, 2014, secured by one self-storage facility with an aggregate net book value of $3.4 million, principal and interest paid monthly (effective interest rate 6.45%)		958		983
	5.99% mortgage notes due May 1, 2026, secured by one self-storage facility with an aggregate net book value of $4.4 million, principal and interest paid monthly (effective interest rate 6.20%)		2,284		2,372
	Total mortgages payable	$	3,242	$	4,251
Summary of Debt Obligation and Interest Rate Derivatives	'
	Accordingly, the estimates presented below are not necessarily indicative of the amounts the Company would realize in a current market exchange.
		Expected Maturity Date Including Discount
	(dollars in thousands)	2013		2014		2015		2016		2017		Thereafter		Total		Fair
																Value
	Line of credit - variable rate LIBOR + 1.50% (1.68% at September 30, 2013)		—		—		—		—		—	$	49,000	$	49,000	$	49,000
	Notes Payable:
	Term note - fixed rate 6.38%		—		—		—	$	150,000		—		—	$	150,000	$	169,366
	Term note - variable rate LIBOR+1.65% (1.83% at September 30, 2013)		—		—		—		—		—	$	225,000	$	225,000	$	225,000
	Term note - variable rate LIBOR+1.65% (1.83% at September 30, 2013)		—		—		—		—		—	$	100,000	$	100,000	$	100,000
	Term note - fixed rate 5.54%		—		—		—		—		—	$	100,000	$	100,000	$	113,978
	Mortgage note - fixed rate 6.35%	$	9	$	949		—		—		—		—	$	958	$	978
	Mortgage notes - fixed rate 5.99%	$	30	$	126	$	134	$	142	$	151	$	1,701	$	2,284	$	2,396
	Interest rate derivatives – asset		—		—		—		—		—		—		—	($	166	)
	Interest rate derivatives – liability		—		—		—		—		—		—		—	$	10,524

Derivative_Financial_Instrumen1

Derivative Financial Instruments (Tables)	9 Months Ended
	Sep. 30, 2013
Derivative Instruments And Hedging Activities Disclosure [Abstract]	'
Summary of Interest Rate Swap Agreements	'
	The Company has interest rate swap agreements in effect at September 30, 2013 as detailed below to effectively convert a total of $325 million of variable-rate debt to fixed-rate debt.
	Notional Amount	Effective			Expiration			Fixed Rate			Floating
		Date			Date			Paid			Rate Received
	$125 Million		9/1/11			8/1/18			2.37	%		1 month LIBOR
	$100 Million		12/30/11			12/29/17			1.6125	%		1 month LIBOR
	$100 Million		9/4/13			9/4/18			1.371	%		1 month LIBOR
	$100 Million		12/29/17			11/29/19			3.968	%		1 month LIBOR
	$125 Million		8/1/18			6/1/20			4.193	%		1 month LIBOR
Summary of Changes in AOCL	'
	The changes in AOCL for the three and nine months ended September 30, 2013 and September 30, 2012 are summarized as follows:
	(dollars in thousands)	Jul. 1, 2013			Jul. 1, 2012			Jan. 1, 2013			Jan. 1, 2012
		to			to			to			to
		Sep. 30, 2013			Sep. 30, 2012			Sep. 30, 2013			Sep. 30, 2012
	Accumulated other comprehensive loss beginning of period	$	(6,481	)	$	(14,482	)	$	(15,242	)	$	(10,255	)
	Realized loss reclassified from accumulated other comprehensive loss to interest expense		1,474			1,425			3,979			3,707
	Unrealized gain (loss) from changes in the fair value of the effective portion of the interest rate swaps		(5,046	)		(3,167	)		1,210			(9,676	)
	Gain (loss) included in other comprehensive loss		(3,572	)		(1,742	)		5,189			(5,969	)
	Accumulated other comprehensive loss end of period	$	(10,053	)	$	(16,224	)	$	(10,053	)	$	(16,224	)

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2013
Fair Value Disclosures [Abstract]	'
Assets and Liabilities Carried at Fair Value Measured on Recurring Basis	'
	The following table provides the assets and liabilities carried at fair value measured on a recurring basis as of September 30, 2013 (in thousands):
		Asset (Liability)			Level 1		Level 2			Level 3
	Interest rate swaps		166			—		166			—
	Interest rate swaps		(10,524	)		—		(10,524	)		—

Investment_in_Joint_Ventures_T

Investment in Joint Ventures (Tables)	9 Months Ended
	Sep. 30, 2013
Equity Method Investments And Joint Ventures [Abstract]	'
Summary of Unconsolidated Joint Ventures' Financial Statements	'
	A summary of the unconsolidated joint ventures’ financial statements as of and for the nine months ended September 30, 2013 is as follows:
	(dollars in thousands)	Sovran HHF			Sovran HHF			Iskalo Office
		Storage			Storage			Holdings, LLC
		Holdings LLC			Holdings II LLC
	Balance Sheet Data:
	Investment in storage facilities, net	$	158,622		$	188,635		$	—
	Investment in office building		—			—			4,968
	Other assets		5,294			5,190			909
	Total Assets	$	163,916		$	193,825		$	5,877
	Due to the Company	$	428		$	358		$	—
	Mortgages payable		45,341			103,776			6,474
	Other liabilities		3,118			2,329			933
	Total Liabilities		48,887			106,463			7,407
	Unaffiliated partners’ equity (deficiency)		92,023			74,263			(1,053	)
	Company equity (deficiency)		23,006			13,099			(477	)
	Total Partners’ Equity (Deficiency)		115,029			87,362			(1,530	)
	Total Liabilities and Partners’ Equity (Deficiency)	$	163,916		$	193,825		$	5,877
	Income Statement Data:
	Total revenues	$	15,766		$	20,007		$	954
	Property operating expenses		(5,108	)		(7,021	)		(383	)
	Administrative, management and call center fees		(1,191	)		(1,490	)		—
	Depreciation and amortization of customer list		(2,841	)		(3,120	)		(170	)
	Amortization of financing fees		(84	)		(152	)		(9	)
	Income tax expense		(53	)		(212	)		—
	Interest expense		(2,710	)		(3,895	)		(303	)
	Net income	$	3,779		$	4,117		$	89

Earnings_Per_Share_Tables

Earnings Per Share (Tables)	9 Months Ended
	Sep. 30, 2013
Earnings Per Share [Abstract]	'
Computation of Basic and Diluted Earnings Per Common Share	'
	The following table sets forth the computation of basic and diluted earnings per common share utilizing the two-class method.
	(in thousands except per share data)	Three Months		Three Months		Nine Months		Nine Months
		Ended		Ended		Ended		Ended
		Sep. 30, 2013		Sep. 30, 2012		Sep. 30, 2013		Sep. 30, 2012
	Numerator:
	Net income from continuing operations attributable to common shareholders	$	19,675	$	14,024	$	51,892	$	35,040
	Denominator:
	Denominator for basic earnings per share – weighted average shares		31,469		29,475		31,078		29,048
	Effect of Dilutive Securities:
	Stock options and non-vested stock		157		149		157		120
	Denominator for diluted earnings per share – adjusted weighted average shares and assumed conversion		31,626		29,624		31,235		29,168
	Basic earnings per common share from continuing operations attributable to common shareholders	$	0.63	$	0.48	$	1.67	$	1.2
	Basic earnings per common share attributable to common shareholders	$	0.63	$	0.64	$	1.67	$	1.43
	Diluted earnings per common share from continuing operations attributable to common shareholders	$	0.62	$	0.47	$	1.66	$	1.2
	Diluted earnings per common share attributable to common shareholders	$	0.62	$	0.63	$	1.66	$	1.43

Organization_Additional_Inform

Organization - Additional Information (Detail) (USD $)	9 Months Ended	12 Months Ended	9 Months Ended	1 Months Ended
	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2013	Feb. 28, 2013	Jun. 30, 2011	Sep. 30, 2013	Sep. 30, 2013
	State		Sales [Member]	West Deptford JV LLC [Member]	West Deptford JV LLC [Member]	Sovran HHF Storage Holdings LLC [Member]	Sovran HHF Storage Holdings II LLC [Member]
	Property		Texas and Florida [Member]			Property	Property
Organization [Line Items]	'	'	'	'	'	'	'
Number of self-storage properties owned and managed	471	'	'	'	'	'	'
Number of states in which self-storage properties owned and managed	25	'	'	'	'	'	'
Number of properties owned and managed under twenty-percent stake joint venture	'	'	'	'	'	25	'
Percentage ownership in unconsolidated joint venture	'	'	'	'	'	20.00%	15.00%
Number of properties owned and managed under fifteen-percent stake joint venture	'	'	'	'	'	'	30
Number of properties managed with no ownership	20	'	'	'	'	'	'
Concentration risk, percentage	'	'	40.00%	'	'	'	'
Percentage of ownership interest of the subsidiary and its limited partnership which controls the operations of the Operating Partnership	99.40%	'	'	'	'	'	'
Payments to acquire businesses and interest in affiliates	'	'	'	'	$4,200,000	'	'
Mortgage note acquired	'	'	'	'	2,800,000	'	'
Interest rate for mortgage note acquired	'	'	'	'	8.00%	'	'
Percentage ownership in consolidated joint venture	'	'	'	'	20.00%	'	'
Payments to acquire preferred interest in affiliates	'	'	'	'	1,400,000	'	'
Preferred interest in investment	'	'	'	'	8.00%	'	'
Membership Interest Purchase Agreement, common and preferred interests	'	'	'	1,400,000	'	'	'
Joint venture partner repaid	'	'	'	2,800,000	'	'	'
Gain on sale of real estate	$421,000	'	'	$400,000	'	'	'
Units of redeemable noncontrolling interest in operating partnership	199,163	204,028	'	'	'	'	'
Noncontrolling limited partnership unit redemption value	'one common share or cash	'	'	'	'	'	'

Organization_Summary_of_Redeem

Organization - Summary of Redeemable Noncontrolling Interest (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Organization Consolidation And Presentation Of Financial Statements [Abstract]	'	'	'	'
Beginning balance noncontrolling redeemable Operating Partnership Units	'	'	$12,670	'
Redemption of Operating Partnership Units	'	'	-306	'
Redemption value in excess of carrying value for Units redeemed	'	'	4	'
Net income attributable to noncontrolling interests	124	151	331	421
Distributions	'	'	-297	'
Adjustment to redemption value	'	'	2,514	'
Ending balance noncontrolling redeemable Operating Partnership Units	$14,916	'	$14,916	'

Stock_Based_Compensation_Addit

Stock Based Compensation - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]	'	'	'	'
Compensation expense related to stock options	$43,000	$59,000	$261,000	$238,000
Amortization of non-vested stock grants	$795,000	$597,000	$1,977,000	$1,794,000
Stock options exercised by employees	23,835	31,435	121,845	77,620
Number of shares of non-vested stock that vested	13,334	13,334	32,796	49,807

Investment_in_Storage_Faciliti2

Investment in Storage Facilities - Summary of Activity in Storage Facilities (Detail) (USD $)	9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013
Cost:	'
Beginning balance	$1,755,954
Acquisition of storage facilities	49,466
Improvements and equipment additions	14,929
Net increase in construction in progress	4,559
Dispositions and impairments	-4,797
Ending balance	1,820,111
Accumulated Depreciation:	'
Beginning balance	328,952
Depreciation expense during the period	31,436
Dispositions	-327
Ending balance	$360,061

Investment_in_Storage_Faciliti3

Investment in Storage Facilities - Additional Information (Detail) (USD $)	9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012
	Facility
Real Estate [Abstract]	'	'
Number of storage facilities acquired	6	'
Amortization period for in-place customer leases on a straight-line basis	'12 months	'
Amortization expense related to in-place customer leases	$2.70	$2.80
Amortization expense for the year	$3.30	'

Investment_in_Storage_Faciliti4

Investment in Storage Facilities - Schedule of Acquired Facilities and Purchase Price of Facilities (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
			Facility
Finite-Lived Intangible Assets [Line Items]	'	'	'	'
Number of Properties	'	'	6	'
Purchase Price	$50,240	'	$50,240	'
Cash Paid	'	'	50,193	105,137
Loan Assumed	'	'	'	'
Net Other Liabilities (Assets) Assumed	47	'	47	'
Land	7,960	'	7,960	'
Building, Equipment, and Improvements	41,506	'	41,506	'
In-Place Customers Leases	774	'	774	'
Closing Costs Expensed	776	1,075	1,263	2,382
Texas [Member] | Date of Acquisition, 2/11/2013 [Member]	'	'	'	'
Finite-Lived Intangible Assets [Line Items]	'	'	'	'
Number of Properties	'	'	1	'
Date of Acquisition	'	'	11-Feb-13	'
Purchase Price	2,400	'	2,400	'
Cash Paid	'	'	2,382	'
Loan Assumed	'	'	'	'
Net Other Liabilities (Assets) Assumed	18	'	18	'
Land	337	'	337	'
Building, Equipment, and Improvements	2,005	'	2,005	'
In-Place Customers Leases	58	'	58	'
Closing Costs Expensed	'	'	145	'
New York [Member] | Date of Acquisition, 3/22/2013 [Member]	'	'	'	'
Finite-Lived Intangible Assets [Line Items]	'	'	'	'
Number of Properties	'	'	1	'
Date of Acquisition	'	'	22-Mar-13	'
Purchase Price	11,050	'	11,050	'
Cash Paid	'	'	11,119	'
Loan Assumed	'	'	'	'
Net Other Liabilities (Assets) Assumed	-69	'	-69	'
Land	2,122	'	2,122	'
Building, Equipment, and Improvements	8,736	'	8,736	'
In-Place Customers Leases	192	'	192	'
Closing Costs Expensed	'	'	264	'
New York [Member] | Date of Acquisition, 8/29/2013 [Member]	'	'	'	'
Finite-Lived Intangible Assets [Line Items]	'	'	'	'
Number of Properties	'	'	2	'
Date of Acquisition	'	'	29-Aug-13	'
Purchase Price	22,000	'	22,000	'
Cash Paid	'	'	21,985	'
Loan Assumed	'	'	'	'
Net Other Liabilities (Assets) Assumed	15	'	15	'
Land	3,320	'	3,320	'
Building, Equipment, and Improvements	18,378	'	18,378	'
In-Place Customers Leases	302	'	302	'
Closing Costs Expensed	'	'	506	'
Massachusetts [Member] | Date of Acquisition, 3/22/2013 [Member]	'	'	'	'
Finite-Lived Intangible Assets [Line Items]	'	'	'	'
Number of Properties	'	'	1	'
Date of Acquisition	'	'	22-Mar-13	'
Purchase Price	8,850	'	8,850	'
Cash Paid	'	'	8,848	'
Loan Assumed	'	'	'	'
Net Other Liabilities (Assets) Assumed	2	'	2	'
Land	1,553	'	1,553	'
Building, Equipment, and Improvements	7,186	'	7,186	'
In-Place Customers Leases	111	'	111	'
Closing Costs Expensed	'	'	161	'
Colorado [Member] | Date of Acquisition, 9/30/2013 [Member]	'	'	'	'
Finite-Lived Intangible Assets [Line Items]	'	'	'	'
Number of Properties	'	'	1	'
Date of Acquisition	'	'	30-Sep-13	'
Purchase Price	5,940	'	5,940	'
Cash Paid	'	'	5,859	'
Loan Assumed	'	'	'	'
Net Other Liabilities (Assets) Assumed	81	'	81	'
Land	628	'	628	'
Building, Equipment, and Improvements	5,201	'	5,201	'
In-Place Customers Leases	111	'	111	'
Closing Costs Expensed	'	'	$187	'

Investment_in_Storage_Faciliti5

Investment in Storage Facilities - Schedule of Fair Value of In-Place Customer Lease Intangible Assets (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Real Estate [Abstract]	'	'
In-place customer leases	$13,893	$13,228
Accumulated amortization	-12,910	-10,337
Net carrying value at the end of period	$983	$2,891

Discontinued_Operations_Additi

Discontinued Operations - Additional Information (Detail) (USD $)	2 Months Ended	3 Months Ended	9 Months Ended
	Aug. 31, 2012	Sep. 30, 2012	Sep. 30, 2012
	Facility
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]	'	'	'
Number of non-strategic storage facilities sold by company	17	'	'
Sales of non-strategic storage facilities	$47,700,000	'	'
Gain on sale of non-strategic storage facilities	$4,500,000	$4,498,000	$4,498,000
Maryland [Member]	'	'	'
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]	'	'	'
Number of non-strategic storage facilities sold by company	1	'	'
Michigan [Member]	'	'	'
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]	'	'	'
Number of non-strategic storage facilities sold by company	4	'	'
Texas [Member]	'	'	'
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]	'	'	'
Number of non-strategic storage facilities sold by company	12	'	'

Discontinued_Operations_Summar

Discontinued Operations - Summary of Amount Reported as Discontinued Operations (Detail) (USD $)	2 Months Ended	3 Months Ended	9 Months Ended
In Thousands, unless otherwise specified	Aug. 31, 2012	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Discontinued Operations And Disposal Groups [Abstract]	'	'	'	'
Total revenue	'	'	$0	$5,144
Property operations and maintenance expense	'	'	'	-1,601
Real estate tax expense	'	'	'	-561
Depreciation and amortization expense	'	'	'	-787
Net realized gain on sale of property	4,500	4,498	'	4,498
Total income from discontinued operations	'	$4,821	$0	$6,693

Unsecured_Line_of_Credit_and_T2

Unsecured Line of Credit and Term Notes - Borrowings Outstanding on Unsecured Line of Credit and Term Notes (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Unsecured Line Of Credit And Term Notes [Line Items]	'	'
Revolving line of credit borrowings	$49,000	$105,000
Total term notes payable	575,000	575,000
Term Note Due September 4, 2013 One [Member]	'	'
Unsecured Line Of Credit And Term Notes [Line Items]	'	'
Total term notes payable	'	20,000
Term Note Due September, 4 2013 Two [Member]	'	'
Unsecured Line Of Credit And Term Notes [Line Items]	'	'
Total term notes payable	'	80,000
Term Note Due April 13, 2016 [Member]	'	'
Unsecured Line Of Credit And Term Notes [Line Items]	'	'
Total term notes payable	150,000	150,000
Term Note Due August 3, 2018 [Member]	'	'
Unsecured Line Of Credit And Term Notes [Line Items]	'	'
Total term notes payable	'	225,000
Term Note Due June 4, 2020 [Member]	'	'
Unsecured Line Of Credit And Term Notes [Line Items]	'	'
Total term notes payable	225,000	'
Term Note Due June 4, 2020 Second [Member]	'	'
Unsecured Line Of Credit And Term Notes [Line Items]	'	'
Total term notes payable	100,000	'
Term Note Due August 5, 2021 [Member]	'	'
Unsecured Line Of Credit And Term Notes [Line Items]	'	'
Total term notes payable	$100,000	$100,000

Unsecured_Line_of_Credit_and_T3

Unsecured Line of Credit and Term Notes - Additional Information (Detail) (USD $)	9 Months Ended			9 Months Ended		9 Months Ended
	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2013	Sep. 30, 2013	Jun. 04, 2013	Sep. 30, 2013	Dec. 31, 2012	Jun. 04, 2013
			Maximum [Member]	Maturity on June 4, 2020 [Member]	Maturity on June 4, 2020 [Member]	Maturity on June 4, 2018 [Member]	Maturity on June 4, 2018 [Member]	Term Loan Due in June, 4 2020 [Member]
						MortgageLoan
Unsecured Line Of Credit And Term Notes [Line Items]	'	'	'	'	'	'	'	'
Additional secured commitments	$575,000,000	$575,000,000	'	'	$225,000,000	'	'	$100,000,000
Basis spread over LIBOR	'	'	'	1.65%	'	1.50%	'	'
Revolving line of credit facility agreement	175,000,000	'	250,000,000	'	'	'	'	'
Facility fee	'	'	'	'	'	0.20%	'	'
Interest rate, line of credit facility	'	'	'	'	'	1.68%	2.21%	'
Amount available on unsecured line of credit	'	'	'	'	'	126,000,000	'	'
Number of one year extensions	'	'	'	'	'	2	'	'
Line of credit facility, expiration date	'	'	'	4-Jun-20	'	4-Jun-18	'	'
Extension facility fee	0.13%	'	'	'	'	'	'	'
Fees and other costs paid	500,000	'	'	'	'	'	'	'
Unsecured term note portion	$1,100,000	'	'	'	'	'	'	'

Mortgages_Payable_and_Debt_Mat2

Mortgages Payable and Debt Maturities - Summary of Mortgage Payable (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Debt Instrument [Line Items]	'	'
Mortgages payable	$3,242	$4,251
6.76% Mortgage Note Due September 11, 2013 [Member]	'	'
Debt Instrument [Line Items]	'	'
Mortgages payable	'	896
6.35% Mortgage Note Due March 11, 2014 [Member]	'	'
Debt Instrument [Line Items]	'	'
Mortgages payable	958	983
5.99% Mortgage Notes Due May 1, 2026 [Member]	'	'
Debt Instrument [Line Items]	'	'
Mortgages payable	$2,284	$2,372

Mortgages_Payable_and_Debt_Mat3

Mortgages Payable and Debt Maturities - Summary of Mortgage Payable (Parenthetical) (Detail) (USD $)	9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013
	Facility
6.76% Mortgage Note Due September 11, 2013 [Member]	'
Debt Instrument [Line Items]	'
Term note stated interest rate	6.76%
Mortgage note due date	11-Sep-13
Self-storage facilities	1
6.35% Mortgage Note Due March 11, 2014 [Member]	'
Debt Instrument [Line Items]	'
Term note stated interest rate	6.35%
Mortgage note due date	11-Mar-14
Self-storage facilities	1
Aggregate net book value of property pledged for mortgage note	3.4
Effective interest rate	6.45%
5.99% Mortgage Notes Due May 1, 2026 [Member]	'
Debt Instrument [Line Items]	'
Term note stated interest rate	5.99%
Mortgage note due date	1-May-26
Self-storage facilities	1
Aggregate net book value of property pledged for mortgage note	4.4
Effective interest rate	6.20%

Mortgages_Payable_and_Debt_Mat4

Mortgages Payable and Debt Maturities - Summary of Debt Obligation and Interest Rate Derivatives (Detail) (USD $)	Sep. 30, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Proforma Debt Instrument [Line Items]	'	'
Line of credit	$49,000	$105,000
Term notes	575,000	575,000
Mortgage note, total	3,242	4,251
Interest rate derivatives - asset	-166	'
Interest rate derivatives - liability	10,524	15,707
Line of Credit-Variable Rate LIBOR + 1.50% (1.68% at September 30, 2013) [Member]	'	'
Proforma Debt Instrument [Line Items]	'	'
Payables due Thereafter	49,000	'
Line of credit	49,000	'
Debt instrument, fair value	49,000	'
Term Note-Fixed Rate 6.38% [Member]	'	'
Proforma Debt Instrument [Line Items]	'	'
Payables due 2016	150,000	'
Term notes	150,000	'
Term note, fair value	169,366	'
Term Note - Variable Rate LIBOR+1.65% (1.83% at September 30, 2013) [Member]	'	'
Proforma Debt Instrument [Line Items]	'	'
Payables due Thereafter	225,000	'
Term notes	225,000	'
Term note, fair value	225,000	'
Term Note - Variable Rate LIBOR+1.65% (1.83% at September 30, 2013) [Member]	'	'
Proforma Debt Instrument [Line Items]	'	'
Payables due Thereafter	100,000	'
Term notes	100,000	'
Term note, fair value	100,000	'
Term Note-Fixed Rate 5.54% [Member]	'	'
Proforma Debt Instrument [Line Items]	'	'
Payables due Thereafter	100,000	'
Term notes	100,000	'
Term note, fair value	113,978	'
Mortgage Note-Fixed Rate 6.35% [Member]	'	'
Proforma Debt Instrument [Line Items]	'	'
Payables due 2013	9	'
Payables due 2014	949	'
Mortgage note, total	958	'
Debt instrument, fair value	978	'
Mortgage Note-Fixed Rate 5.99% [Member]	'	'
Proforma Debt Instrument [Line Items]	'	'
Payables due 2013	30	'
Payables due 2014	126	'
Payables due 2015	134	'
Payables due 2016	142	'
Payables due 2017	151	'
Payables due Thereafter	1,701	'
Mortgage note, total	2,284	'
Debt instrument, fair value	$2,396	'

Mortgages_Payable_and_Debt_Mat5

Mortgages Payable and Debt Maturities - Summary of Debt Obligation and Interest Rate Derivatives (Parenthetical) (Detail)	9 Months Ended
	Sep. 30, 2013
Line of Credit-Variable Rate LIBOR + 1.50% (1.68% at September 30, 2013) [Member]	'
Proforma Debt Instrument [Line Items]	'
Interest rate at end of period	1.68%
Basis spread rate over LIBOR	1.50%
Term Note-Fixed Rate 6.38% [Member]	'
Proforma Debt Instrument [Line Items]	'
Interest rate at end of period	6.38%
Term Note - Variable Rate LIBOR+1.65% (1.83% at September 30, 2013) [Member]	'
Proforma Debt Instrument [Line Items]	'
Interest rate at end of period	1.83%
Basis spread rate over LIBOR	1.65%
Term Note - Variable Rate LIBOR+1.65% (1.83% at September 30, 2013) [Member]	'
Proforma Debt Instrument [Line Items]	'
Interest rate at end of period	1.83%
Basis spread rate over LIBOR	1.65%
Term Note-Fixed Rate 5.54% [Member]	'
Proforma Debt Instrument [Line Items]	'
Interest rate at end of period	5.54%
Mortgage Note-Fixed Rate 6.35% [Member]	'
Proforma Debt Instrument [Line Items]	'
Interest rate at end of period	6.35%
Mortgage Note-Fixed Rate 5.99% [Member]	'
Proforma Debt Instrument [Line Items]	'
Interest rate at end of period	5.99%

Derivative_Financial_Instrumen2

Derivative Financial Instruments - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Derivative [Line Items]	'	'	'	'	'
Interest Expense	$7,923,000	$8,350,000	$24,827,000	$24,914,000	'
Estimated payments to be made under interest rate swaps	'	'	5,400,000	'	'
Fair value of interest rate swap agreements	10,524,000	'	10,524,000	'	15,707,000
Estimated payments to be made under interest rate swaps, assets	166,000	'	166,000	'	'
Reclassification Out of Accumulated Other Comprehensive Income [Member] | Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member]	'	'	'	'	'
Derivative [Line Items]	'	'	'	'	'
Interest Expense	'	'	4,000,000	3,700,000	'
Interest Rate Swap [Member]	'	'	'	'	'
Derivative [Line Items]	'	'	'	'	'
Notional amount	$325,000,000	'	$325,000,000	'	'

Derivative_Financial_Instrumen3

Derivative Financial Instruments - Summary of Interest Rate Swap Agreements (Detail) (USD $)	9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013
Interest Rate Swap [Member]	'
Derivative [Line Items]	'
Notional amount	$125
Effective Date	1-Sep-11
Expiration Date	1-Aug-18
Fixed Rate Paid	2.37%
Floating Rate Received	'1 month LIBOR
Interest Rate Swap One [Member]	'
Derivative [Line Items]	'
Notional amount	100
Effective Date	30-Dec-11
Expiration Date	29-Dec-17
Fixed Rate Paid	1.61%
Floating Rate Received	'1 month LIBOR
Interest Rate Swap Two [Member]	'
Derivative [Line Items]	'
Notional amount	100
Effective Date	4-Sep-13
Expiration Date	4-Sep-18
Fixed Rate Paid	1.37%
Floating Rate Received	'1 month LIBOR
Interest Rate Swap Three [Member]	'
Derivative [Line Items]	'
Notional amount	100
Effective Date	29-Dec-17
Expiration Date	29-Nov-19
Fixed Rate Paid	3.97%
Floating Rate Received	'1 month LIBOR
Interest Rate Swap Four [Member]	'
Derivative [Line Items]	'
Notional amount	$125
Effective Date	1-Aug-18
Expiration Date	1-Jun-20
Fixed Rate Paid	4.19%
Floating Rate Received	'1 month LIBOR

Derivative_Financial_Instrumen4

Derivative Financial Instruments - Summary of Changes in AOCL (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Derivative [Line Items]	'	'	'	'
Accumulated other comprehensive loss beginning of period	($6,481)	($14,482)	($15,242)	($10,255)
Unrealized gain (loss) from changes in the fair value of the effective portion of the interest rate swaps	-5,046	-3,167	1,210	-9,676
Gain (loss) included in other comprehensive loss	-3,572	-1,742	5,189	-5,969
Accumulated other comprehensive loss end of period	-10,053	-16,224	-10,053	-16,224
Reclassification Out of Accumulated Other Comprehensive Income [Member] | Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member]	'	'	'	'
Derivative [Line Items]	'	'	'	'
Realized loss reclassified from accumulated other comprehensive loss to interest expense	$1,474	$1,425	$3,979	$3,707

Fair_Value_Measurements_Assets

Fair Value Measurements - Assets and Liabilities Carried at Fair Value Measured on Recurring Basis (Detail) (Interest Rate Swap [Member], USD $)	Sep. 30, 2013
In Thousands, unless otherwise specified
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]	'
Interest rate swaps	$166
Interest rate swaps	-10,524
Level 1 [Member]	'
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]	'
Interest rate swaps	'
Interest rate swaps	'
Level 2 [Member]	'
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]	'
Interest rate swaps	166
Interest rate swaps	-10,524
Level 3 [Member]	'
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]	'
Interest rate swaps	'
Interest rate swaps	'

Fair_Value_Measurements_Additi

Fair Value Measurements - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2013
	Facility
Fair Value Disclosures [Abstract]	'
Number of storage facilities acquired	6

Investment_in_Joint_Ventures_A

Investment in Joint Ventures - Additional Information (Detail) (USD $)

3 Months Ended

9 Months Ended

3 Months Ended

9 Months Ended

9 Months Ended

12 Months Ended

9 Months Ended

12 Months Ended

3 Months Ended

9 Months Ended

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2013

Sep. 30, 2012

Dec. 31, 2012

Sep. 30, 2013

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2008

Sep. 30, 2013

Sep. 30, 2012

Dec. 31, 2012

Dec. 31, 2011

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2013

Sep. 30, 2012

Iskalo Office Holdings, LLC [Member]

Iskalo Office Holdings, LLC [Member]

Iskalo Office Holdings, LLC [Member]

Iskalo Office Holdings, LLC [Member]

Iskalo Office Holdings, LLC [Member]

Sovran HHF Storage Holdings LLC [Member]

Sovran HHF Storage Holdings LLC [Member]

Sovran HHF Storage Holdings LLC [Member]

Sovran HHF Storage Holdings LLC [Member]

Sovran HHF Storage Holdings II LLC [Member]

Sovran HHF Storage Holdings II LLC [Member]

Sovran HHF Storage Holdings II LLC [Member]

Sovran HHF Storage Holdings II LLC [Member]

Sovran HHF and Sovran HHF II [Member]

Sovran HHF and Sovran HHF II [Member]

Sovran HHF and Sovran HHF II [Member]

Sovran HHF and Sovran HHF II [Member]

Property

Property

Property

Schedule of Equity Method Investments [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Ownership interest

'

'

'

'

49.00%

'

49.00%

'

'

20.00%

'

'

'

15.00%

'

'

'

'

'

'

'

Investment at carrying value

'

'

'

'

($500,000)

'

($500,000)

'

($500,000)

$24,700,000

'

'

'

$13,100,000

'

'

'

'

'

'

'

Payment for property acquisition

50,240,000

'

50,240,000

'

'

'

'

'

'

'

'

'

171,500,000

'

'

29,000,000

166,100,000

'

'

'

'

Number of properties owned and managed under twenty-percent stake joint venture

'

'

'

'

'

'

'

'

'

'

'

'

25

'

'

'

'

'

'

'

'

Contribution of company to joint venture as share in capital

'

'

'

'

'

'

200,000

'

'

3,900,000

1,200,000

800,000

18,600,000

200,000

'

2,400,000

12,800,000

'

'

'

'

Excess of investment over net asset due to capitalization of acquisition related costs

'

'

'

'

'

'

'

'

'

1,700,000

'

'

'

'

'

'

'

'

'

'

'

Number of properties owned and managed under fifteen-percent stake joint venture

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

10

20

'

'

'

'

Management and call center fee as a percentage of revenues

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

7.00%

'

Management and call center fee earned

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

900,000

800,000

2,500,000

2,200,000

Acquisition fees received for securing purchases

'

'

'

'

'

'

'

'

'

'

'

'

'

0

200,000

'

'

'

'

'

'

Company's share in income (loss) of joint venture

$575,000

$335,000

$1,417,000

$608,000

$23,000

($4,000)

$44,000

$9,000

'

'

'

'

'

'

'

'

'

$600,000

$300,000

$1,400,000

$600,000

Investment_in_Joint_Ventures_S

Investment in Joint Ventures - Summary of Unconsolidated Joint Ventures' Financial Statements (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Schedule of Equity Method Investments [Line Items]	'	'	'	'	'
Investment in storage facilities, net	$1,460,050	'	$1,460,050	'	$1,427,002
Other assets	5,584	'	5,584	'	6,676
Total Assets	1,523,262	'	1,523,262	'	1,484,441
Mortgages payable	3,242	'	3,242	'	4,251
Total Liabilities	677,948	'	677,948	'	743,041
Depreciation and amortization of customer list	-11,381	-10,427	-34,118	-30,461	'
Amortization of financing fees	'	'	-640	-627	'
Income tax expense	-300	-600	-1,000	-1,600	'
Interest expense	-7,923	-8,350	-24,827	-24,914	'
Sovran HHF Storage Holdings LLC [Member]	'	'	'	'	'
Schedule of Equity Method Investments [Line Items]	'	'	'	'	'
Investment in storage facilities, net	158,622	'	158,622	'	'
Investment in office building	'	'	'	'	'
Other assets	5,294	'	5,294	'	'
Total Assets	163,916	'	163,916	'	'
Due to the Company	428	'	428	'	'
Mortgages payable	45,341	'	45,341	'	'
Other liabilities	3,118	'	3,118	'	'
Total Liabilities	48,887	'	48,887	'	'
Unaffiliated partners' equity (deficiency)	92,023	'	92,023	'	'
Company equity (deficiency)	23,006	'	23,006	'	'
Total Partners' Equity (Deficiency)	115,029	'	115,029	'	'
Total Liabilities and Partners' Equity (Deficiency)	163,916	'	163,916	'	'
Total revenues	'	'	15,766	'	'
Property operating expenses	'	'	-5,108	'	'
Administrative, management and call center fees	'	'	-1,191	'	'
Depreciation and amortization of customer list	'	'	-2,841	'	'
Amortization of financing fees	'	'	-84	'	'
Income tax expense	'	'	-53	'	'
Interest expense	'	'	-2,710	'	'
Net income	'	'	3,779	'	'
Sovran HHF Storage Holdings II LLC [Member]	'	'	'	'	'
Schedule of Equity Method Investments [Line Items]	'	'	'	'	'
Investment in storage facilities, net	188,635	'	188,635	'	'
Investment in office building	'	'	'	'	'
Other assets	5,190	'	5,190	'	'
Total Assets	193,825	'	193,825	'	'
Due to the Company	358	'	358	'	'
Mortgages payable	103,776	'	103,776	'	'
Other liabilities	2,329	'	2,329	'	'
Total Liabilities	106,463	'	106,463	'	'
Unaffiliated partners' equity (deficiency)	74,263	'	74,263	'	'
Company equity (deficiency)	13,099	'	13,099	'	'
Total Partners' Equity (Deficiency)	87,362	'	87,362	'	'
Total Liabilities and Partners' Equity (Deficiency)	193,825	'	193,825	'	'
Total revenues	'	'	20,007	'	'
Property operating expenses	'	'	-7,021	'	'
Administrative, management and call center fees	'	'	-1,490	'	'
Depreciation and amortization of customer list	'	'	-3,120	'	'
Amortization of financing fees	'	'	-152	'	'
Income tax expense	'	'	-212	'	'
Interest expense	'	'	-3,895	'	'
Net income	'	'	4,117	'	'
Iskalo Office Holdings, LLC [Member]	'	'	'	'	'
Schedule of Equity Method Investments [Line Items]	'	'	'	'	'
Investment in storage facilities, net	'	'	'	'	'
Investment in office building	4,968	'	4,968	'	'
Other assets	909	'	909	'	'
Total Assets	5,877	'	5,877	'	'
Due to the Company	'	'	'	'	'
Mortgages payable	6,474	'	6,474	'	'
Other liabilities	933	'	933	'	'
Total Liabilities	7,407	'	7,407	'	'
Unaffiliated partners' equity (deficiency)	-1,053	'	-1,053	'	'
Company equity (deficiency)	-477	'	-477	'	'
Total Partners' Equity (Deficiency)	-1,530	'	-1,530	'	'
Total Liabilities and Partners' Equity (Deficiency)	5,877	'	5,877	'	'
Total revenues	'	'	954	'	'
Property operating expenses	'	'	-383	'	'
Administrative, management and call center fees	'	'	'	'	'
Depreciation and amortization of customer list	'	'	-170	'	'
Amortization of financing fees	'	'	-9	'	'
Income tax expense	'	'	'	'	'
Interest expense	'	'	-303	'	'
Net income	'	'	$89	'	'

Income_Taxes_Additional_Inform

Income Taxes - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Income Tax Disclosure [Abstract]	'	'	'	'
Federal and state income tax expense	$0.30	$0.60	$1	$1.60
Deferred tax liability	1	'	1	'
Tax years open to examination	'	'	'2010-2012	'
Unrecognized tax benefits	0	0	0	0
Interest or penalties related to uncertain tax positions	'	'	$0	'

Earnings_Per_Share_Computation

Earnings Per Share - Computation of Basic and Diluted Earnings Per Common Share (Detail) (USD $)	3 Months Ended		9 Months Ended
In Thousands, except Share data, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Numerator:	'	'	'	'
Net income from continuing operations attributable to common shareholders	$19,675	$14,024	$51,892	$35,040
Denominator:	'	'	'	'
Denominator for basic earnings per share - weighted average shares	31,469,026	29,474,866	31,077,910	29,047,998
Effect of Dilutive Securities:	'	'	'	'
Stock options and non-vested stock	157,000	149,000	157,000	120,000
Denominator for diluted earnings per share - adjusted weighted average shares and assumed conversion	31,625,635	29,624,311	31,235,049	29,167,681
Basic earnings per common share from continuing operations attributable to common shareholders	$0.63	$0.48	$1.67	$1.20
Basic earnings per common share attributable to common shareholders	$0.63	$0.64	$1.67	$1.43
Diluted earnings per common share from continuing operations attributable to common shareholders	$0.62	$0.47	$1.66	$1.20
Diluted earnings per common share attributable to common shareholders	$0.62	$0.63	$1.66	$1.43

Earnings_Per_Share_Additional_

Earnings Per Share - Additional Information (Detail)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Stock Options [Member]	'	'	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'	'	'
Securities not included in the effect of dilutive securities	'	9,500	2,667	41,833
Restricted Stock [Member]	'	'	'	'
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]	'	'	'	'
Securities not included in the effect of dilutive securities	121,916	108,949	88,901	131,525

Shareholders_Equity_Additional

Shareholders' Equity - Additional Information (Detail) (USD $)	3 Months Ended	9 Months Ended
In Millions, except Share data, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2013	Feb. 27, 2013
		Facility
Stockholders Equity [Line Items]	'	'	'
Common stock value authorized under equity offering program	'	'	$175
Common stock shares issued under equity offering program	444,910	1,266,910	'
Weighted average issue price of common stock	$72.11	$65.58	'
Proceeds from issuance of common stock	31.6	81.9	'
Expenses related to equity program	'	0.1	'
Common stock, value reserved for future issuance	91.9	91.9	'
Acquired storage facilities	'	6	'
Jefferies [Member]	'	'	'
Stockholders Equity [Line Items]	'	'	'
Offering related costs and commissions	0.5	0.5	'
SunTrust [Member]	'	'	'
Stockholders Equity [Line Items]	'	'	'
Offering related costs and commissions	'	0.5	'
Wells Fargo [Member]	'	'	'
Stockholders Equity [Line Items]	'	'	'
Offering related costs and commissions	'	$0.20	'

Commitment_and_Contingencies_A

Commitment and Contingencies - Additional Information (Detail) (USD $)	Sep. 30, 2013
In Millions, unless otherwise specified	Facility
Commitments And Contingencies Disclosure [Abstract]	'
Payment for self-storage facilities under contract	$6.30
Number of self-storage facilities under contract to be purchased	1

Subsequent_Events_Additional_I

Subsequent Events - Additional Information (Detail) (USD $)	2 Months Ended	3 Months Ended	9 Months Ended			1 Months Ended			1 Months Ended
	Aug. 31, 2012	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Nov. 30, 2013	Oct. 30, 2013	Oct. 02, 2013	Oct. 30, 2013
	Facility				Purchase Option [Member]	Subsequent Event [Member]	Subsequent Event [Member]	Subsequent Event [Member]	Subsequent Event [Member]
						Facility			Ohio [Member]
									Facility
Subsequent Event [Line Items]	'	'	'	'	'	'	'	'	'
Dividend declared, date	'	'	2-Oct-13	'	'	'	'	'	'
Dividend per common share	'	'	'	'	'	'	'	$0.53	'
Dividend paid, date	'	'	28-Oct-13	'	'	'	'	'	'
Dividend record, date	'	'	14-Oct-13	'	'	'	'	'	'
Dividend paid	'	'	'	'	'	'	$16,900,000	'	'
Number of non-strategic storage facilities sold by company	17	'	'	'	'	'	'	'	1
Proceeds from divestiture of businesses	47,700,000	'	'	'	'	'	3,200,000	'	'
Gain form sale of non-strategic storage facilities	4,500,000	4,498,000	'	4,498,000	'	'	300,000	'	'
Number of self storage facilities under lease	'	'	'	'	'	4	'	'	'
Annual lease payments	'	'	'	'	'	6,000,000	'	'	'
Lease agreement, purchase option	'	'	'	'	'	$120,000,000	'	'	'
Annual Increase in Lease Payments	'	'	'	'	'	4.00%	'	'	'
Lease beginning date	'	'	1-Nov-13	'	'	'	'	'	'
Lease ending date	'	'	31-Dec-28	'	'	'	'	'	'
Purchase option initiation date	'	'	'	'	2-Feb-15	'	'	'	'
Purchase option expiration date	'	'	'	'	2-Sep-16	'	'	'	'