Life Storage Inc - Registered Shares (LSI) 10-Q 4 May 16 2016 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2016	Apr. 22, 2016
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2016
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	Q1
Trading Symbol	SSS
Entity Registrant Name	SOVRAN SELF STORAGE INC
Entity Central Index Key	944,314
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		39,444,553

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Investment in storage facilities:
Land	$ 594,879	$ 480,176
Building, equipment, and construction in progress	2,238,107	2,011,526
Real estate investment property, at cost, total	2,832,986	2,491,702
Less: accumulated depreciation	(479,859)	(465,195)
Investment in storage facilities, net	2,353,127	2,026,507
Cash and cash equivalents	6,373	7,032
Accounts receivable	4,203	6,805
Receivable from unconsolidated joint ventures	659	929
Investment in unconsolidated joint ventures	64,985	62,520
Prepaid expenses	7,236	5,431
Fair value of interest rate swap agreements		550
Other assets	12,900	9,048
Total Assets	2,449,483	2,118,822
Liabilities
Line of credit	141,000	79,000
Term notes, net of financing fees	746,831	746,650
Accounts payable and accrued liabilities	38,065	47,839
Deferred revenue	8,138	7,511
Fair value of interest rate swap agreements	26,846	15,343
Mortgages payable	1,959	1,993
Total Liabilities	962,839	898,336
Noncontrolling redeemable Operating Partnership Units at redemption value	24,213	18,171
Shareholders' Equity
Common stock $.01 par value, 100,000,000 shares authorized, 39,399,691 shares outstanding at March 31, 2016 (36,710,673 at December 31, 2015)	394	367
Additional paid-in capital	1,664,549	1,388,343
Dividends in excess of net income	(176,429)	(171,980)
Accumulated other comprehensive loss	(26,511)	(14,415)
Total Shareholders' Equity	1,462,003	1,202,315
Noncontrolling interest in consolidated subsidiary	428
Total Equity	1,462,431	1,202,315
Total Liabilities and Shareholders' Equity	$ 2,449,483	$ 2,118,822

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Mar. 31, 2016	Dec. 31, 2015
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	39,399,691	36,710,673

Consolidated Statements of Oper

Consolidated Statements of Operations (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Revenues
Rental income	$ 91,541	$ 78,886
Other operating income	7,583	6,522
Total operating revenues	99,124	85,408
Expenses
Property operations and maintenance	22,861	20,559
Real estate taxes	10,547	8,920
General and administrative	10,464	9,406
Acquisition costs	2,384	582
Operating leases of storage facilities		683
Depreciation and amortization	16,425	14,181
Total operating expenses	62,681	54,331
Income from operations	36,443	31,077
Other income (expenses)
Interest expense	(9,134)	(9,161)
Interest income	6	2
Loss on sale of storage facility		(7)
Equity in income of joint ventures	915	646
Net income	28,230	22,557
Net income attributable to noncontrolling interest in the Operating Partnership	(130)	(106)
Net loss attributable to noncontrolling interest in consolidated subsidiary	239
Net income attributable to common shareholders	$ 28,339	$ 22,451
Earnings per common share attributable to common shareholders - basic	$ 0.74	$ 0.65
Earnings per common share attributable to common shareholders - diluted	$ 0.73	$ 0.65
Common shares used in basic earnings per share calculation	38,410,817	34,329,768
Common shares used in diluted earnings per share calculation	38,663,138	34,554,871
Dividends declared per common share	$ 0.85	$ 0.75

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Statement of Comprehensive Income [Abstract]
Net income	$ 28,230	$ 22,557
Other comprehensive income:
Change in fair value of derivatives net of reclassification to interest expense	(12,096)	(3,987)
Total comprehensive income	16,134	18,570
Comprehensive income attributable to noncontrolling interest in the Operating Partnership	(75)	(87)
Comprehensive loss attributable to noncontrolling interest in consolidated subsidiary	239
Comprehensive income attributable to common shareholders	$ 16,298	$ 18,483

Consolidated Statements of Cash

Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Operating Activities
Net income	$ 28,230	$ 22,557
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	16,425	14,181
Amortization of deferred financing fees	356	296
Loss on sale of storage facility		7
Equity in income of joint ventures	(915)	(646)
Distributions from unconsolidated joint ventures	1,285	1,017
Non-vested stock earned	1,889	1,612
Stock option expense	46	36
Changes in assets and liabilities (excluding the effects of acquisitions):
Accounts receivable	2,645	13
Prepaid expenses	(1,789)	(443)
Receipts from (advances to) joint ventures	270	(145)
Accounts payable and other liabilities	(10,080)	(7,887)
Deferred revenue	(439)	342
Net cash provided by operating activities	37,923	30,940
Investing Activities
Acquisitions of storage facilities	(323,548)	(134,040)
Improvements, equipment additions, and construction in progress	(13,797)	(5,335)
Net proceeds from the sale of storage facility		711
Investment in unconsolidated joint ventures	(2,845)	(285)
Property deposit	(2,372)	(1,095)
Net cash used in investing activities	(342,562)	(140,044)
Financing Activities
Net proceeds from sale of common stock	274,298	122,631
Proceeds from line of credit	310,000	144,000
Repayments of line of credit	(248,000)	(130,000)
Financing costs	(936)
Dividends paid - common stock	(31,204)	(25,609)
Distributions to noncontrolling interest holders	(144)	(117)
Mortgage principal payments	(34)	(32)
Net cash provided by financing activities	303,980	110,873
Net decrease in cash	(659)	1,769
Cash at beginning of period	7,032	8,543
Cash at end of period	6,373	10,312
Supplemental cash flow information
Cash paid for interest, net of interest capitalized	5,689	5,307
Cash (received) paid for income taxes, net of refunds	$ (47)	$ 88

Basis of Presentation

Basis of Presentation	3 Months Ended
	Mar. 31, 2016
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 three month period ended March 31, 2016 are not necessarily indicative of the results that may be expected for the year ending December 31, 2016. Reclassification:

Organization

Organization	3 Months Ended
	Mar. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [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 March 31, 2016, we had an ownership interest in, and/or managed 562 self-storage properties in 26 states under the name Uncle Bob’s Self Storage ®. Among our 562 self-storage properties are 39 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 16 properties that we manage and have no ownership interest. Approximately 41% of the Company’s revenue is derived from stores in the states of Texas and Florida. In addition, approximately 10% of the Company’s revenue is derived from the Houston, Texas market. 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 99.5% ownership interest therein as of March 31, 2016. The remaining ownership interests in the Operating Partnership (the “Units”) are held by certain former owners of assets acquired by the Operating Partnership. 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, Uncle Bob’s Management, LLC (the Company’s taxable REIT subsidiary), Warehouse Anywhere LLC (an entity owned 60% by Uncle Bob’s Management, LLC), Locke Sovran I, LLC (a wholly-owned subsidiary), and Locke Sovran II, LLC (a wholly-owned 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 accounted for using the equity method. 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 March 31, 2016, there were 209,638 noncontrolling redeemable operating partnership Units outstanding (168,866 at December 31, 2015). These unitholders are entitled to receive distributions per unit equivalent to the dividends declared per share on the Company’s common stock. 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 (dollars in thousands) Three Months Beginning balance noncontrolling redeemable Operating Partnership Units $ 18,171 Issuance of Operating Partnership Units 4,472 Net income attributable to noncontrolling interest in the Operating Partnership 130 Distributions (144 ) Adjustment to redemption value 1,584 Ending balance noncontrolling redeemable Operating Partnership Units $ 24,213 In March 2016 the Operating Partnership issued 40,772 Units with a fair market value of $4.5 million to acquire self-storage properties. The fair value of the Units on the date of issuance was determined based upon the fair market value of the Company’s common stock on that date.

Stock Based Compensation

Stock Based Compensation	3 Months Ended
	Mar. 31, 2016
Disclosure of Compensation Related Costs, Share-based 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 For the three months ended March 31, 2016 and 2015, the Company recorded compensation expense (included in general and administrative expense) of $46,000 and $36,000, respectively, related to stock options and $1,866,000 and $1,612,000, respectively, related to amortization of non-vested stock grants and performance-based awards. During the three months ended March 31, 2016 and 2015, employees and directors exercised 0 and 9,500 stock options respectively, and 7,185 and 5,234 shares of non-vested stock, respectively, vested.

Investment in Storage Facilitie

Investment in Storage Facilities	3 Months Ended
	Mar. 31, 2016
Real Estate [Abstract]
Investment in Storage Facilities	4. INVESTMENT IN STORAGE FACILITIES The following summarizes our activity in storage facilities during the three months ended March 31, 2016. (dollars in thousands) Cost: Beginning balance $ 2,491,702 Acquisition of storage facilities 327,408 Improvements and equipment additions 6,651 Additions to consolidated subsidiary 1,815 Net increase in construction in progress 6,106 Dispositions (696 ) Ending balance $ 2,832,986 Accumulated Depreciation: Beginning balance $ 465,195 Additions during the period 15,255 Dispositions (591 ) Ending balance $ 479,859 The Company acquired 25 facilities during the three months ended March 31, 2016. The acquisition of one store that was acquired at certificate of occupancy was accounted for as an asset acquisition. The cost of this store, including closing costs, was assigned to its land, building, equipment and improvements components based upon their relative fair values. The assets and liabilities of the other 24 storage facilities acquired in 2016, 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” (dollars in thousands) Consideration paid Acquisition Date Fair Value State Number of Date of Purchase Price Cash Paid Value of Net Other Land Building, In-Place Closing 2016 Florida 4 1/6/16 $ 20,350 $ 20,246 $ — $ 104 $ 6,646 $ 13,339 $ 365 $ 366 California 4 1/21/16 78,750 78,562 — 188 27,876 49,860 1,014 327 New Hampshire 5 1/21/16 54,225 53,941 — 284 12,902 40,428 895 569 Massachusetts 1 1/21/16 11,375 11,350 — 25 4,874 6,335 166 64 Texas 3 1/21/16 42,050 41,894 — 156 23,487 18,000 563 247 Arizona 1 2/1/16 9,275 9,261 — 14 988 8,224 63 119 Florida 1 2/12/16 11,274 11,270 — 4 2,294 8,980 — — Pennsylvania 1 2/17/16 5,750 5,732 — 18 1,768 3,879 103 147 Colorado 1 2/29/16 12,600 12,549 — 51 4,528 7,915 157 170 California 3 3/16/16 68,832 63,965 4,472 395 22,647 45,371 814 260 California 1 3/17/16 17,320 17,278 — 42 6,728 10,339 253 115 Total acquired 2016 25 $ 331,801 $ 326,048 $ 4,472 $ 1,281 $ 114,738 $ 212,670 $ 4,393 $ 2,384 All of the properties acquired were purchased from unrelated third parties. The operating results of the facilities acquired have been included in the Company’s operations since the respective acquisition dates. Of the $326.0 million paid at closing for the properties acquired during 2016, $2.5 million represented deposits that were paid in 2015 when certain of these properties originally went under contract. In addition to the closing costs expensed on 2016 acquisitions, the Company also incurred $345,000 of acquisition costs in 2015 related to facilities acquired in 2016. Non-cash investing activities during 2016 include the issuance of $4.5 million in Operating Partnership Units. 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: Mar. 31, Dec. 31, (Dollars in thousands) 2016 2015 In-place customer leases $ 26,714 $ 22,320 Accumulated amortization (22,192 ) (21,017 ) Net carrying value at the end of period $ 4,522 $ 1,303 Amortization expense related to in-place customer leases was $1.2 million and $1.0 million for the three months ended March 31, 2016 and 2015, respectively. The Company expects to record $5.2 million and $0.5 million of amortization expense for the years ended December 31, 2016 and 2017, respectively. During 2016, the Company acquired 25 properties. The following pro forma information is based on the combined historical financial statements of the Company and the 25 properties acquired, and presents the Company’s results as if the acquisitions had occurred as of January 1, 2015: Three months Three months Total revenues $ 101,551 $ 90,871 Net income attributable to common shareholders $ 31,745 $ 20,173 Earnings per common share Basic $ 0.81 $ 0.52 Diluted $ 0.81 $ 0.51 The following table summarizes the revenues and earnings related to the 25 properties since the acquisition dates that are included in the Company’s consolidated statements of operations for the three months ended March 31, 2016. Three months Total revenues $ 3,754 Net loss attributable to common shareholders $ (1,760 ) The above net losses attributable to common shareholders were primarily due to the acquisition costs incurred in connection with the 2016 acquisitions. Property Dispositions During 2015 the Company sold three non-strategic properties purchased in 2014 and 2015 with a carrying value of $5.1 million and received cash proceeds of $4.6 million, resulting in a $0.5 million loss on sale. The following table summarizes the revenues and expenses up to the dates of sale of the three properties sold in 2015 that are included in the Company’s consolidated statements of operations for 2015. Jan. 1, 2015 to (Dollars in thousands) Mar. 31, 2015 Total revenues $ 40 Property operations and maintenance expense (16 ) Real estate tax expense (5 ) Depreciation and amortization expense (9 ) Loss on sale of storage facilities (7 ) $ 3

Unsecured Line of Credit and Te

Unsecured Line of Credit and Term Notes	3 Months Ended
	Mar. 31, 2016
Debt Disclosure [Abstract]
Unsecured Line of Credit and Term Notes	5. UNSECURED LINE OF CREDIT AND TERM NOTES Borrowings outstanding on our unsecured line of credit and term notes are as follows: Mar. 31, Dec. 31, (Dollars in thousands) 2016 2015 Revolving line of credit borrowings $ 141,000 $ 79,000 Term note due April 26, 2016 150,000 150,000 Term note due June 4, 2020 325,000 325,000 Term note due August 5, 2021 100,000 100,000 Term note due April 8, 2024 175,000 175,000 Total term notes payable $ 750,000 $ 750,000 On December 10, 2014, the Company amended its existing unsecured credit agreement. In January 2016, the Company exercised the expansion feature of such credit agreement and increased the revolving credit limit from $300 million to $500 million. The interest rate on the revolving credit facility bears interest at a variable rate equal to LIBOR plus a margin based on the Company’s credit rating (at March 31, 2016 the margin is 1.10%), and requires a 0.15% facility fee. The amended agreement also reduced the interest rate on the $325 million unsecured term note maturing June 4, 2020, with the term note bearing interest at LIBOR plus a margin based on the Company’s credit rating (at March 31, 2016 the margin is 1.15%). The interest rate at March 31, 2016 on the Company’s line of credit was approximately 1.53% (1.72% at December 31, 2015). At March 31, 2016, there was $359 million available on the unsecured line of credit. The revolving line of credit has a maturity date of December 10, 2019. On April 8, 2014, the Company entered into a $175 million term note maturing April 2024 bearing interest at a fixed rate of 4.533%. The interest rate on the term note increases to 6.283% if the Company is not rated by at least one rating agency or if the Company’s credit rating is downgraded. The proceeds from this term note were used to repay the $115 million outstanding on the Company’s line of credit at April 8, 2014, with the excess proceeds used for acquisitions. In 2011, the Company entered into a $100 million term note maturing August 5, 2021 bearing interest at a fixed rate of 5.54%. The interest rate on the term note increases to 7.29% if the notes are not rated by at least one rating agency, the credit rating on the notes is downgraded or if the Company’s credit rating is downgraded. The proceeds from this term note were used to fund acquisitions and investments in unconsolidated joint ventures. The Company has maintained a $150 million unsecured term note maturing April 26, 2016 bearing interest at 6.38%. The interest rate on the $150 million unsecured term note increases to 8.13% if the notes are not rated by at least one rating agency, the credit rating on the notes is downgraded or the Company’s credit rating is downgraded. The Company used a draw on the line of credit to pay off the balance of this note on April 26, 2016. During April 2015, the FASB issued ASU No. 2015-03, Interest - Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs, which amends the requirements for the presentation of debt issuance costs and requires that debt issuance costs related to a recognized debt liability be presented in the balance sheet as a direct deduction from the carrying amount of that debt liability, consistent with debt discounts. ASU No. 2015-03 is effective for fiscal years, beginning after December 15, 2015 and interim periods within those fiscal years. The implementation of this update did not cause any material changes to our consolidated financial statements other than the reclassification of $3.2 million and $3.4 million of debt issuance costs from assets to a reduction of term notes on our consolidated balance sheets at March 31, 2016 and 2015, respectively. In August 2015, the FASB issued Accounting Standards Update 2015-15, “Imputation of Interest (Subtopic 835-30): Presentation and Subsequent Measurement of Debt Issuance Costs Associated with Line-of-Credit Arrangements” (“ASU 2015-15”). ASU 2015-15 codifies an SEC staff announcement that entities are permitted to defer and present debt issuance costs related to line-of-credit arrangements as assets. ASU No. 2015-15 is effective for fiscal years, beginning after December 15, 2015 and interim periods within those fiscal years. The implementation of this update did not cause any material changes to our consolidated financial statements. 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 March 31, 2016, 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 March 31, 2016 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 Matu

Mortgages Payable and Debt Maturities	3 Months Ended
	Mar. 31, 2016
Debt Disclosure [Abstract]
Mortgages Payable and Debt Maturities	6. MORTGAGES PAYABLE AND DEBT MATURITIES Mortgages payable at March 31, 2016 and December 31, 2015 consist of the following: (dollars in thousands) March 31, December 31, 5.99% mortgage notes due May 1, 2026, secured by one self-storage facility with an aggregate net book value of $4.3 million, principal and interest paid monthly (effective interest rate 6.24%) 1,959 1,993 Total mortgages payable $ 1,959 $ 1,993 The table below summarizes the Company’s debt obligations and interest rate derivatives at March 31, 2016. 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 8. 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) 2016 2017 2018 2019 2020 Thereafter Total Fair Line of credit - variable rate LIBOR + 1.10% (1.53% at March 31, 2016) — — — $ 141,000 — — $ 141,000 $ 141,000 Notes Payable: Term note - fixed rate 6.38% $ 150,000 — — — — — $ 150,000 $ 153,184 Term note - variable rate LIBOR+1.15% (1.59% at March 31, 2016) — — — — $ 325,000 — $ 325,000 $ 325,000 Term note - fixed rate 5.54% — — — — — $ 100,000 $ 100,000 $ 112,467 Term note - fixed rate 4.533% — — — — — $ 175,000 $ 175,000 $ 186,337 Mortgage note - fixed rate 5.99% $ 108 $ 151 $ 160 $ 170 $ 181 $ 1,189 $ 1,959 $ 2,096 Interest rate derivatives – liability — — — — — — — $ 26,846

Derivative Financial Instrument

Derivative Financial Instruments	3 Months Ended
	Mar. 31, 2016
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Financial Instruments	7. 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. Forward starting interest rate swaps are also used by the Company to hedge the risk of changes in the interest-related cash outflows associated with the potential issuance of long-term debt. 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 into 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 de minimis for the three months ended March 31, 2016, and 2015. The Company has interest rate swap agreements in effect at March 31, 2016 as detailed below to effectively convert a total of $325 million of variable-rate debt to fixed-rate debt, and $150 million notional pre-issuance swap agreements to hedge the risk of changes in interest-related cash outflows associated with a potential issuance of long-term debt. Notional Amount Effective Date Expiration Date Fixed Floating Rate Received $125 Million 9/1/2011 8/1/18 2.3700 % 1 month LIBOR $100 Million 12/30/11 12/29/17 1.6125 % 1 month LIBOR $100 Million 9/4/13 9/4/18 1.3710 % 1 month LIBOR $100 Million 12/29/17 11/29/19 3.9680 % 1 month LIBOR $125 Million 8/1/18 6/1/20 4.1930 % 1 month LIBOR $50 Million 5/31/16 5/31/26 2.1560 % 3 month LIBOR $50 Million 5/31/16 5/31/26 2.1875 % 3 month LIBOR $25 Million 5/31/16 5/31/26 2.0330 % 3 month LIBOR $25 Million 5/31/16 5/31/26 1.9390 % 3 month LIBOR The Company may issue long-term debt in May 2016. The $150 million pre-issuance swap agreements are designated to hedge the risk of interest rate changes associated with this debt issuance. The swaps are intended to be settled on May 31, 2016 and any resulting gain or loss on the swaps at that time will be deferred and recorded as interest expense over the term of the related debt. If the issuance of the debt occurs on a date other than May 31, 2016, there could be ineffectiveness related to the swap agreements which may be recorded as expense at that time. The interest rate swap agreements are the only derivative instruments, as defined by FASB ASC Topic 815 “ Derivatives and Hedging The Company’s agreements with its interest rate swap counterparties contain provisions pursuant to which the Company could be declared in default of its derivative obligations if the Company defaults on any of its indebtedness, including default where repayment of the indebtedness has not been accelerated by the lender. The interest rate swap agreements also incorporate other loan covenants of the Company. Failure to comply with the loan covenant provisions would result in the Company being in default on the interest rate swap agreements. As of March 31, 2016, the Company had not posted any collateral related to the interest rate swap agreements. If the Company had breached any of these provisions as of March 31, 2016, it could have been required to settle its obligations under the agreements at their net termination cost of $26.8 million. The changes in AOCL for the three months ended March 31, 2016 and March 31, 2015 are summarized as follows: (dollars in thousands) Jan. 1, 2016 Jan. 1, 2015 Accumulated other comprehensive loss beginning of period $ (14,415 ) $ (13,005 ) Realized loss reclassified from accumulated other comprehensive loss to interest expense 1,197 1,358 Unrealized loss from changes in the fair value of the effective portion of the interest rate swaps (13,293 ) (5,345 ) Loss included in other comprehensive loss (12,096 ) (3,987 ) Accumulated other comprehensive loss end of period $ (26,511 ) $ (16,992 )

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2016
Fair Value Disclosures [Abstract]
Fair Value Measurements	8. FAIR VALUE MEASUREMENTS The Company applies the provisions of ASC Topic 820 “ Fair Value Measurements and Disclosures Refer to Note 6 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 March 31, 2016 and December 31, 2015 (in thousands): Asset Level 1 Level 2 Level 3 March 31, 2016 Interest rate swaps (26,846 ) — (26,846 ) — December 31, 2015 Interest rate swaps 550 — 550 — Interest rate swaps (15,343 ) — (15,343 ) — 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 2016, 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 25 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 which is considered a Level 2 input. The replacement cost is then adjusted for the age, condition, and economic obsolescence associated with these assets, which are considered Level 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 at 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	3 Months Ended
	Mar. 31, 2016
Equity Method Investments and Joint Ventures [Abstract]
Investment in Joint Ventures	9. 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 March 31, 2016 and December 31, 2015 was $44.3 million and $44.6 million, respectively. Twenty-five properties were acquired by Sovran HHF in 2008 for approximately $171.5 million and 14 additional properties were acquired by Sovran HHF in 2014 for $187.2 million. In 2008, the Company contributed $18.6 million to the joint venture as its share of capital required to fund the acquisitions. In 2012 the Company contributed an additional $1.2 million to the joint venture. In 2013 the Company received a return of capital distribution of $3.4 million as part of the refinancing of Sovran HHF. In 2014 the Company contributed an additional $28.6 million in cash to the joint venture as its share of capital required to fund acquisitions. In 2015 the Company contributed an additional $0.4 million in cash to the joint venture as its share of capital required to fund certain capital expenditures and property taxes related to 2014 acquisitions. As of March 31, 2016, 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 March 31, 2016 and December 31, 2015 was $13.9 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 2012, the Company contributed $2.4 million to the joint venture as its share of capital required to fund the acquisitions. In 2015 the Company contributed an additional $1.7 million in cash to the joint venture as its share of capital required to fund the payoff of a mortgage note. 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 $1.2 million and $1.2 million for the three months ended March 31, 2016 and 2015, respectively. The Company’s share of Sovran HHF and Sovran HHF II’s income for the three months ended March 31, 2016 and 2015 was $0.8 million and $0.6 million, respectively. The Company has a 49% ownership interest in Iskalo Office Holdings, LLC, which owns the building that houses the Company’s headquarters and other tenants. The carrying value of the Company’s investment is a liability of $0.5 million at March 31, 2016 and December 31, 2015, and is included in accounts payable and accrued liabilities in the accompanying consolidated balance sheets. For the three months ended March 31, 2016, and 2015, the Company’s share of Iskalo Office Holdings, LLC’s income was $59,000 and $58,000, respectively. The Company paid rent to Iskalo Office Holdings, LLC of $0.3 million during the three months ended March 31, 2016 and 2015. The Company holds an 85% equity interest in Urban Box Coralway Storage, LLC (Urban Box), a joint venture with an unrelated third party. Urban Box was formed in 2015 and is currently developing a self-storage property in Florida. During 2015, the Company contributed $4.0 million to Urban Box as its share of capital to develop the property, which primarily consists of the acquisition of land in 2015. Urban Box will enter into a non-recourse mortgage loan in order to finance the future development costs. The Company and the other joint venture member have participation rights which require the agreement of both members in order to implement the activities of Urban Box which are most significant to its economic performance. Accordingly, the interest is recorded using the equity method. The Company will perform property management services for Urban Box in exchange for a management fee based on 6% of property revenues. There were no management fees in 2016 or 2015. The Company holds a 5% equity interest in SNL/Orix 1200 McDonald Ave., LLC (McDonald), a joint venture with an unrelated third party. The joint venture for McDonald was executed in 2016 and is currently developing a self-storage property in New York. During 2016, the Company contributed $0.4 million of common capital and $2.3 million of preferred capital to McDonald as its share of capital to develop the property. McDonald will enter into a non-recourse mortgage loan in order to finance the future development costs. In accordance with the terms of the McDonald joint venture agreement, the Company has the ability to assert influence over certain business matters. Accordingly, the interest is recorded using the equity method. The Company will perform property management services for McDonald in exchange for a management fee based on property revenues. There were no management fees in 2016 or 2015. A summary of the unconsolidated joint ventures’ financial statements as of and for the three months ended March 31, 2016 is as follows: dollars in thousands) Balance Sheet Data: Investment in storage facilities, net $ 527,662 Investment in office building 5,007 Other assets 17,238 Total Assets $ 549,907 Due to the Company $ 672 Mortgages payable 223,401 Other liabilities 6,006 Total Liabilities 230,079 Unaffiliated partners’ equity 257,098 Company equity 62,730 Total Partners’ Equity 319,828 Total Liabilities and Partners’ Equity (Deficiency) $ 549,907 Income Statement Data: Total revenues $ 18,005 Property operating expenses (5,951 ) Administrative, management and call center fees (1,303 ) Depreciation and amortization of customer list (3,106 ) Amortization of financing fees (89 ) Income tax expense (58 ) Interest expense (2,574 ) Net income $ 4,924 The Company does not guarantee the debt of Sovran HHF, Sovran HHF II, Iskalo Office Holdings, LLC, Urban Box, or McDonald. We do not expect to have material future cash outlays relating to these joint ventures outside our share of capital for future acquisitions of properties.

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2016
Income Tax Disclosure [Abstract]
Income Taxes	10. 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 one of its subsidiaries 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 March 31, 2016 and 2015, the Company recorded federal and state income tax expense of $0.6 million and $0.4 million, respectively. At March 31, 2016 and 2015, 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 March 31, 2016 and 2015, the Company had no interest or penalties related to uncertain tax positions. Net income taxes payable and the deferred tax liability of our taxable REIT subsidiary are classified within accounts payable and accrued liabilities in the consolidated balance sheet. As of March 31, 2016, the Company’s taxable REIT subsidiary has current prepaid taxes of $0.1 million and a deferred tax liability of $1.3 million. The tax years 2013-2015 remain open to examination by the major taxing jurisdictions to which the Company is subject.

Earnings Per Share

Earnings Per Share	3 Months Ended
	Mar. 31, 2016
Earnings Per Share [Abstract]
Earnings Per Share	11. EARNINGS PER SHARE The Company reports earnings per share data in accordance ASC Topic 260, “ Earnings Per Share Determining Whether Instruments Granted in Share-Based Payment Transactions Are Participating Securities” Three Months Three Months (in thousands except per share data) Mar. 31, 2016 Mar. 31, 2015 Numerator: Net income attributable to common shareholders $ 28,339 $ 22,451 Denominator: Denominator for basic earnings per share – weighted average shares 38,411 34,330 Effect of Dilutive Securities: Stock options and non-vested stock 252 225 Denominator for diluted earnings per share – adjusted weighted average shares and assumed conversion 38,663 34,555 Basic earnings per common share attributable to common shareholders $ 0.74 $ 0.65 Diluted earnings per common share attributable to common shareholders $ 0.73 $ 0.65 Not included in the effect of dilutive securities above are 130,573 unvested restricted shares for the three months ended March 31, 2016, and 171,220 unvested restricted shares for the three months ended March 31, 2015, because their effect would be antidilutive.

Shareholders' Equity

Shareholders' Equity	3 Months Ended
	Mar. 31, 2016
Equity [Abstract]
Shareholders' Equity	12. SHAREHOLDERS’ EQUITY The following is a reconciliation of the changes in total shareholders’ equity for the period: (dollars in thousands) Three Months Beginning balance of total shareholders’ equity $ 1,202,315 Net proceeds from the issuance of common stock 274,298 Exercise of stock options — Earned portion of non-vested stock 1,866 Stock option expense 46 Deferred compensation - directors 23 Adjustment to redemption value on noncontrolling redeemable Operating Partnership units (1,584 ) Net income attributable to common shareholders 28,339 Change in fair value of derivatives (12,096 ) Dividends (31,204 ) Ending balance of total shareholders’ equity $ 1,462,003 On January 20, 2016, the Company completed the public offering of 2,645,000 shares of its common stock at $105.75 per share. Net proceeds to the Company after deducting underwriting discounts and commissions and offering expenses were approximately $269.7 million. The Company used the net proceeds from the offering to repay a portion of the indebtedness outstanding on the Company’s unsecured line of credit. On May 12, 2014, the Company entered into a continuous equity offering program (“Equity Program”) with Wells Fargo Securities, LLC (“Wells Fargo”), Jefferies LLC (“Jefferies”), SunTrust Robinson Humphrey, Inc. (“SunTrust”), Piper Jaffray & Co. (“Piper”), HSBC Securities (USA) Inc. (“HSBC”), and BB&T Capital Markets, a division of BB&T Securities, LLC (“BB&T”), pursuant to which the Company may sell from time to time up to $225 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 March 31, 2016 and 2015, the Company did not issue any shares of common stock under the Equity Program. As of March 31, 2016, the Company had $59.3 million available for issuance under the Equity Program. In 2013, the Company implemented a Dividend Reinvestment Plan. The Company issued 44,018 shares under the plan during the three months ended March 31, 2016.

Recent Accounting Pronouncement

Recent Accounting Pronouncements	3 Months Ended
	Mar. 31, 2016
Accounting Changes and Error Corrections [Abstract]
Recent Accounting Pronouncements	13. RECENT ACCOUNTING PRONOUNCEMENTS In May 2014, the FASB issued ASU 2014-09, “Revenue from Contracts with Customers,” which supersedes the revenue recognition requirements in “Revenue Recognition (Topic 605),” and requires an entity to recognize revenue in a way that depicts the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled to in exchange for those goods or services. ASU 2014-09 is effective for fiscal years, and interim periods within those years, beginning after December 15, 2017. The Company has the option to apply the provisions of ASU 2014-09 either retrospectively to each prior reporting period presented or retrospectively with the cumulative effect of initially applying the new guidance recognized at the date of initial application. The Company has not yet completed its assessment of the impact that the adoption of ASU 2014-09 will have on its consolidated financial statements. In June 2014, the FASB issued ASU 2014-12, “Accounting for Share-Based Payments When the Terms of an Award Provide That a Performance Target Could Be Achieved after the Requisite Service Period,” which requires a reporting entity to treat a performance target that affects vesting and that could be achieved after the requisite service period as a performance condition. ASU 2014-12 is effective for annual periods, and interim periods within those annual periods, beginning after December 15, 2015. Early adoption is permitted. ASU 2014-12 may be adopted either prospectively for share-based payment awards granted or modified on or after the effective date, or retrospectively, using a modified retrospective approach. The modified retrospective approach would apply to share-based payment awards outstanding as of the beginning of the earliest annual period presented in the financial statements on adoption, and to all new or modified awards thereafter. The adoption of ASU 2014-12 by the Company did not have a material impact on its consolidated financial statements. In February 2015, the FASB issued ASU 2015-02, “Consolidation (Topic 810): Amendments to the Consolidation Analysis”. This ASU is effective for annual reporting periods beginning after December 15, 2015 including interim periods within that reporting period. ASU 2015-02 amends the current consolidation model specifically as it relates to variable interest entities (“VIE’s”) and provides reporting entities with a revised consolidation analysis procedure. The adoption of ASU 2015-02 by the Company did not have a material impact on its consolidated financial statements. In September 2015, the FASB issued ASU 2015-16, “Business Combinations (Topic 805): Simplifying the Accounting for Measurement-Period Adjustments”. ASU 2015-16 requires that an acquirer recognize adjustments to provisional amounts that are identified during the measurement period in the reporting period in which the adjustment amounts are determined. ASU 2015-16 is effective for fiscal years, and interim reporting periods within those fiscal years, beginning after December 15, 2015. The adoption of ASU 2015-16 by the Company did not have a material impact on its consolidated financial statements. In February 2016, the FASB issued ASU 2016-02, “Leases (Topic 842)”. This guidance revises existing practice related to accounting for leases under Accounting Standards Codification Topic 840 Leases In March 2016, the FASB issued ASU 2016-06, “Derivatives and Hedging (Topic 815): Contingent Put and Call Options in Debt Instruments”. ASU 2016-06 simplifies the embedded derivative analysis for debt instruments containing contingent call or put options by removing the requirement to assess whether a contingent event is related to interest rates or credit risks. The new standard will be effective for us on January 1, 2017. The Company has not yet completed its assessment of the impact that the adoption of ASU 2016-06 will have on its consolidated financial statements. In March 2016, the FASB issued ASU 2016-07, “Investments - Equity Method and Joint Ventures (Topic 323): Simplifying the Transition to the Equity Method of Accounting”. ASU 2016-07 eliminates the requirement that when an investment qualifies for use of the equity method as a result of an increase in the level of ownership interest or degree of influence, an adjustment must be made to the investment, results of operations, and retained earnings retroactively on a step-by-step basis as if the equity method had been in effect during all previous periods that the investment had been held. The new standard will be effective for us on January 1, 2017. The Company has not yet completed its assessment of the impact that the adoption of ASU 2016-07 will have on its consolidated financial statements. In March 2016, the FASB issued ASU 2016-09, “Improvements to Employee Share-Based Payment Accounting” as part of its simplification initiative, which involves several aspects of accounting for share-based payment transactions, including the income tax consequences, classification of awards as either equity or liabilities, and classification on the statement of cash flows. The amendments in this update are effective for annual periods beginning after December 15, 2016, and interim periods within those annual periods. The Company has not yet completed its assessment of the impact that the adoption of ASU 2016-09 will have on its consolidated financial statements.

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	14. COMMITMENT AND CONTINGENCIES At March 31, 2016, the Company was under contract to acquire 13 self-storage facilities for aggregate consideration of approximately $146.4 million. Six of the facilities were acquired in April and May of 2016 for $86.7 million. The Company has not yet determined the assignment of the purchase prices of these six facilities to the individual assets acquired. These acquisitions were funded with draws on the Company’s line of credit. The purchase of the remaining facilities by the Company is subject to customary conditions to closing, and there is no assurance that these facilities will be acquired. On or about August 25, 2014, a putative class action was filed against the Company in the Superior Court of New Jersey Law Division Burlington County. The action seeks to obtain declaratory, injunctive and monetary relief for a class of consumers based upon alleged violations by the Company of the New Jersey Truth in Customer Contract, Warranty and Notice Act, the New Jersey Consumer Fraud Act and the New Jersey Insurance Producer Licensing Act. On October 17, 2014, the action was removed from the Superior Court of New Jersey Law Division Burlington County to the United States District Court for the District of New Jersey. The Company brought a motion to partially dismiss the complaint for failure to state a claim, and on July 16, 2015, the Company’s motion was granted in part and denied in part. The Company intends to vigorously defend the action, and the possibility of any adverse outcome cannot be determined at this time.

Subsequent Events

Subsequent Events	3 Months Ended
	Mar. 31, 2016
Subsequent Events [Abstract]
Subsequent Events	15. SUBSEQUENT EVENTS On April 1, 2016, the Company declared a quarterly dividend of $0.95 per common share. The dividend was paid on April 26, 2016 to shareholders of record on April 14, 2016. The total dividend paid amounted to $37.3 million. On April 26, 2016, the Company repaid the outstanding balance of the maturing $150 million term note with a draw on its line of credit. The line of credit balance outstanding after the funding of this repayment and six acquisitions was $390 million. On April 13, 2016, the Company entered into a contract to sell 8 self-storage facilities for a total sales price of $35.0 million. The sale of the facilities by the Company is subject to customary conditions to closing, and there is no assurance that these facilities will be sold.

Basis of Presentation (Policies

Basis of Presentation (Policies)	3 Months Ended
	Mar. 31, 2016
Accounting Changes and Error Corrections [Abstract]
Reclassification	Reclassification:
Fair Value Measurements and Disclosures	The assets and liabilities of the other 24 storage facilities acquired in 2016, 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”
Revenue from Contracts with Customers	In May 2014, the FASB issued ASU 2014-09, “Revenue from Contracts with Customers,” which supersedes the revenue recognition requirements in “Revenue Recognition (Topic 605),” and requires an entity to recognize revenue in a way that depicts the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled to in exchange for those goods or services. ASU 2014-09 is effective for fiscal years, and interim periods within those years, beginning after December 15, 2017. The Company has the option to apply the provisions of ASU 2014-09 either retrospectively to each prior reporting period presented or retrospectively with the cumulative effect of initially applying the new guidance recognized at the date of initial application. The Company has not yet completed its assessment of the impact that the adoption of ASU 2014-09 will have on its consolidated financial statements.
Accounting for Share-Based Payments	In June 2014, the FASB issued ASU 2014-12, “Accounting for Share-Based Payments When the Terms of an Award Provide That a Performance Target Could Be Achieved after the Requisite Service Period,” which requires a reporting entity to treat a performance target that affects vesting and that could be achieved after the requisite service period as a performance condition. ASU 2014-12 is effective for annual periods, and interim periods within those annual periods, beginning after December 15, 2015. Early adoption is permitted. ASU 2014-12 may be adopted either prospectively for share-based payment awards granted or modified on or after the effective date, or retrospectively, using a modified retrospective approach. The modified retrospective approach would apply to share-based payment awards outstanding as of the beginning of the earliest annual period presented in the financial statements on adoption, and to all new or modified awards thereafter. The adoption of ASU 2014-12 by the Company did not have a material impact on its consolidated financial statements.
Consolidation Variable Interest Entity	In February 2015, the FASB issued ASU 2015-02, “Consolidation (Topic 810): Amendments to the Consolidation Analysis”. This ASU is effective for annual reporting periods beginning after December 15, 2015 including interim periods within that reporting period. ASU 2015-02 amends the current consolidation model specifically as it relates to variable interest entities (“VIE’s”) and provides reporting entities with a revised consolidation analysis procedure. The adoption of ASU 2015-02 by the Company did not have a material impact on its consolidated financial statements.
Business Combinations	In September 2015, the FASB issued ASU 2015-16, “Business Combinations (Topic 805): Simplifying the Accounting for Measurement-Period Adjustments”. ASU 2015-16 requires that an acquirer recognize adjustments to provisional amounts that are identified during the measurement period in the reporting period in which the adjustment amounts are determined. ASU 2015-16 is effective for fiscal years, and interim reporting periods within those fiscal years, beginning after December 15, 2015. The adoption of ASU 2015-16 by the Company did not have a material impact on its consolidated financial statements.
Leases	In February 2016, the FASB issued ASU 2016-02, “Leases (Topic 842)”. This guidance revises existing practice related to accounting for leases under Accounting Standards Codification Topic 840 Leases

Organization (Tables)

Organization (Tables)	3 Months Ended
	Mar. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [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) Three Months Beginning balance noncontrolling redeemable Operating Partnership Units $ 18,171 Issuance of Operating Partnership Units 4,472 Net income attributable to noncontrolling interest in the Operating Partnership 130 Distributions (144 ) Adjustment to redemption value 1,584 Ending balance noncontrolling redeemable Operating Partnership Units $ 24,213

Investment in Storage Facilit24

Investment in Storage Facilities (Tables)	3 Months Ended
	Mar. 31, 2016
Real Estate [Abstract]
Summary of Activity in Storage Facilities	The following summarizes our activity in storage facilities during the three months ended March 31, 2016. (dollars in thousands) Cost: Beginning balance $ 2,491,702 Acquisition of storage facilities 327,408 Improvements and equipment additions 6,651 Additions to consolidated subsidiary 1,815 Net increase in construction in progress 6,106 Dispositions (696 ) Ending balance $ 2,832,986 Accumulated Depreciation: Beginning balance $ 465,195 Additions during the period 15,255 Dispositions (591 ) Ending balance $ 479,859
Schedule of Acquired Facilities and Purchase Price of Facilities	The purchase price of the 25 facilities acquired in 2016 has been preliminarily assigned as follows: (dollars in thousands) Consideration paid Acquisition Date Fair Value State Number of Date of Purchase Price Cash Paid Value of Net Other Land Building, In-Place Closing 2016 Florida 4 1/6/16 $ 20,350 $ 20,246 $ — $ 104 $ 6,646 $ 13,339 $ 365 $ 366 California 4 1/21/16 78,750 78,562 — 188 27,876 49,860 1,014 327 New Hampshire 5 1/21/16 54,225 53,941 — 284 12,902 40,428 895 569 Massachusetts 1 1/21/16 11,375 11,350 — 25 4,874 6,335 166 64 Texas 3 1/21/16 42,050 41,894 — 156 23,487 18,000 563 247 Arizona 1 2/1/16 9,275 9,261 — 14 988 8,224 63 119 Florida 1 2/12/16 11,274 11,270 — 4 2,294 8,980 — — Pennsylvania 1 2/17/16 5,750 5,732 — 18 1,768 3,879 103 147 Colorado 1 2/29/16 12,600 12,549 — 51 4,528 7,915 157 170 California 3 3/16/16 68,832 63,965 4,472 395 22,647 45,371 814 260 California 1 3/17/16 17,320 17,278 — 42 6,728 10,339 253 115 Total acquired 2016 25 $ 331,801 $ 326,048 $ 4,472 $ 1,281 $ 114,738 $ 212,670 $ 4,393 $ 2,384
Schedule of Fair Value of In-Place Customer Lease Intangible Assets	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: Mar. 31, Dec. 31, (Dollars in thousands) 2016 2015 In-place customer leases $ 26,714 $ 22,320 Accumulated amortization (22,192 ) (21,017 ) Net carrying value at the end of period $ 4,522 $ 1,303
Pro Forma Information Based on Combined Historical Financial Statements on Properties Acquired	The following pro forma information is based on the combined historical financial statements of the Company and the 25 properties acquired, and presents the Company’s results as if the acquisitions had occurred as of January 1, 2015: Three months Three months Total revenues $ 101,551 $ 90,871 Net income attributable to common shareholders $ 31,745 $ 20,173 Earnings per common share Basic $ 0.81 $ 0.52 Diluted $ 0.81 $ 0.51
Summary of Revenues and Earnings Related to Properties Included in Company's Consolidated Statements of Operations	The following table summarizes the revenues and earnings related to the 25 properties since the acquisition dates that are included in the Company’s consolidated statements of operations for the three months ended March 31, 2016. Three months Total revenues $ 3,754 Net loss attributable to common shareholders $ (1,760 )
Summary of Revenues and Expenses Related to Sale of Properties Included in Company's Consolidated Statements of Operations	The following table summarizes the revenues and expenses up to the dates of sale of the three properties sold in 2015 that are included in the Company’s consolidated statements of operations for 2015. Jan. 1, 2015 to (Dollars in thousands) Mar. 31, 2015 Total revenues $ 40 Property operations and maintenance expense (16 ) Real estate tax expense (5 ) Depreciation and amortization expense (9 ) Loss on sale of storage facilities (7 ) $ 3

Unsecured Line of Credit and 25

Unsecured Line of Credit and Term Notes (Tables)	3 Months Ended
	Mar. 31, 2016
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: Mar. 31, Dec. 31, (Dollars in thousands) 2016 2015 Revolving line of credit borrowings $ 141,000 $ 79,000 Term note due April 26, 2016 150,000 150,000 Term note due June 4, 2020 325,000 325,000 Term note due August 5, 2021 100,000 100,000 Term note due April 8, 2024 175,000 175,000 Total term notes payable $ 750,000 $ 750,000

Mortgages Payable and Debt Ma26

Mortgages Payable and Debt Maturities (Tables)	3 Months Ended
	Mar. 31, 2016
Debt Disclosure [Abstract]
Summary of Mortgage Payable	Mortgages payable at March 31, 2016 and December 31, 2015 consist of the following: (dollars in thousands) March 31, December 31, 5.99% mortgage notes due May 1, 2026, secured by one self-storage facility with an aggregate net book value of $4.3 million, principal and interest paid monthly (effective interest rate 6.24%) 1,959 1,993 Total mortgages payable $ 1,959 $ 1,993
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) 2016 2017 2018 2019 2020 Thereafter Total Fair Line of credit - variable rate LIBOR + 1.10% (1.53% at March 31, 2016) — — — $ 141,000 — — $ 141,000 $ 141,000 Notes Payable: Term note - fixed rate 6.38% $ 150,000 — — — — — $ 150,000 $ 153,184 Term note - variable rate LIBOR+1.15% (1.59% at March 31, 2016) — — — — $ 325,000 — $ 325,000 $ 325,000 Term note - fixed rate 5.54% — — — — — $ 100,000 $ 100,000 $ 112,467 Term note - fixed rate 4.533% — — — — — $ 175,000 $ 175,000 $ 186,337 Mortgage note - fixed rate 5.99% $ 108 $ 151 $ 160 $ 170 $ 181 $ 1,189 $ 1,959 $ 2,096 Interest rate derivatives – liability — — — — — — — $ 26,846

Derivative Financial Instrume27

Derivative Financial Instruments (Tables)	3 Months Ended
	Mar. 31, 2016
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Summary of Interest Rate Swap Agreements	The Company has interest rate swap agreements in effect at March 31, 2016 as detailed below to effectively convert a total of $325 million of variable-rate debt to fixed-rate debt, and $150 million notional pre-issuance swap agreements to hedge the risk of changes in interest-related cash outflows associated with a potential issuance of long-term debt. Notional Amount Effective Date Expiration Date Fixed Floating Rate Received $125 Million 9/1/2011 8/1/18 2.3700 % 1 month LIBOR $100 Million 12/30/11 12/29/17 1.6125 % 1 month LIBOR $100 Million 9/4/13 9/4/18 1.3710 % 1 month LIBOR $100 Million 12/29/17 11/29/19 3.9680 % 1 month LIBOR $125 Million 8/1/18 6/1/20 4.1930 % 1 month LIBOR $50 Million 5/31/16 5/31/26 2.1560 % 3 month LIBOR $50 Million 5/31/16 5/31/26 2.1875 % 3 month LIBOR $25 Million 5/31/16 5/31/26 2.0330 % 3 month LIBOR $25 Million 5/31/16 5/31/26 1.9390 % 3 month LIBOR
Summary of Changes in AOCL	The changes in AOCL for the three months ended March 31, 2016 and March 31, 2015 are summarized as follows: (dollars in thousands) Jan. 1, 2016 Jan. 1, 2015 Accumulated other comprehensive loss beginning of period $ (14,415 ) $ (13,005 ) Realized loss reclassified from accumulated other comprehensive loss to interest expense 1,197 1,358 Unrealized loss from changes in the fair value of the effective portion of the interest rate swaps (13,293 ) (5,345 ) Loss included in other comprehensive loss (12,096 ) (3,987 ) Accumulated other comprehensive loss end of period $ (26,511 ) $ (16,992 )

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2016
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 March 31, 2016 and December 31, 2015 (in thousands): Asset Level 1 Level 2 Level 3 March 31, 2016 Interest rate swaps (26,846 ) — (26,846 ) — December 31, 2015 Interest rate swaps 550 — 550 — Interest rate swaps (15,343 ) — (15,343 ) —

Investment in Joint Ventures (T

Investment in Joint Ventures (Tables)	3 Months Ended
	Mar. 31, 2016
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 three months ended March 31, 2016 is as follows: dollars in thousands) Balance Sheet Data: Investment in storage facilities, net $ 527,662 Investment in office building 5,007 Other assets 17,238 Total Assets $ 549,907 Due to the Company $ 672 Mortgages payable 223,401 Other liabilities 6,006 Total Liabilities 230,079 Unaffiliated partners’ equity 257,098 Company equity 62,730 Total Partners’ Equity 319,828 Total Liabilities and Partners’ Equity (Deficiency) $ 549,907 Income Statement Data: Total revenues $ 18,005 Property operating expenses (5,951 ) Administrative, management and call center fees (1,303 ) Depreciation and amortization of customer list (3,106 ) Amortization of financing fees (89 ) Income tax expense (58 ) Interest expense (2,574 ) Net income $ 4,924

Earnings Per Share (Tables)

Earnings Per Share (Tables)	3 Months Ended
	Mar. 31, 2016
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. Three Months Three Months (in thousands except per share data) Mar. 31, 2016 Mar. 31, 2015 Numerator: Net income attributable to common shareholders $ 28,339 $ 22,451 Denominator: Denominator for basic earnings per share – weighted average shares 38,411 34,330 Effect of Dilutive Securities: Stock options and non-vested stock 252 225 Denominator for diluted earnings per share – adjusted weighted average shares and assumed conversion 38,663 34,555 Basic earnings per common share attributable to common shareholders $ 0.74 $ 0.65 Diluted earnings per common share attributable to common shareholders $ 0.73 $ 0.65

Shareholders' Equity (Tables)

Shareholders' Equity (Tables)	3 Months Ended
	Mar. 31, 2016
Equity [Abstract]
Reconciliation of Changes in Total Shareholders' Equity	The following is a reconciliation of the changes in total shareholders’ equity for the period: (dollars in thousands) Three Months Beginning balance of total shareholders’ equity $ 1,202,315 Net proceeds from the issuance of common stock 274,298 Exercise of stock options — Earned portion of non-vested stock 1,866 Stock option expense 46 Deferred compensation - directors 23 Adjustment to redemption value on noncontrolling redeemable Operating Partnership units (1,584 ) Net income attributable to common shareholders 28,339 Change in fair value of derivatives (12,096 ) Dividends (31,204 ) Ending balance of total shareholders’ equity $ 1,462,003

Organization - Additional Infor

Organization - Additional Information (Detail) $ in Thousands	3 Months Ended
	Mar. 31, 2016USD ($)StatesPropertyshares	Dec. 31, 2015shares	Dec. 31, 2012Property	Dec. 31, 2011Property	Dec. 31, 2008Property
Organization [Line Items]
Number of self-storage properties owned and managed	562
Number of states in which self-storage properties owned and managed | States	26
Number of properties managed with no ownership	16
Percentage of ownership interest of the subsidiary and its limited partnership which controls the operations of the Operating Partnership	99.50%
Units of redeemable noncontrolling interest in operating partnership | shares	209,638	168,866
Noncontrolling limited partnership unit redemption value	One common share or cash
Number of units issued for acquisition | shares	40,772
Fair value of units, issued for acquisition | $	$ 4,472
Sovran HHF Storage Holdings LLC [Member]
Organization [Line Items]
Number of properties owned and managed under twenty-percent stake joint venture	39				25
Percentage ownership in unconsolidated joint venture	20.00%
Sovran HHF Storage Holdings II LLC [Member]
Organization [Line Items]
Percentage of variable interest ownership in unconsolidated joint venture	15.00%
Number of properties owned and managed under fifteen-percent stake joint venture	30		10	20
Uncle Bob's Management, LLC [Member]
Organization [Line Items]
Percentage of ownership by subsidiary	60.00%
Geographic Concentration Risk [Member] | Texas and Florida [Member] | Revenue [Member]
Organization [Line Items]
Concentration risk, percentage	41.00%
Geographic Concentration Risk [Member] | Houston Texas [Member] | Revenue [Member]
Organization [Line Items]
Concentration risk, percentage	10.00%

Organization - Summary of Redee

Organization - Summary of Redeemable Noncontrolling Interest (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Redeemable Noncontrolling Interest, Equity, Fair Value [Abstract]
Beginning balance noncontrolling redeemable Operating Partnership Units	$ 18,171
Issuance of Operating Partnership Units	4,472
Net income attributable to noncontrolling interest in the Operating Partnership	130	$ 106
Distributions	(144)
Adjustment to redemption value	1,584
Ending balance noncontrolling redeemable Operating Partnership Units	$ 24,213

Stock Based Compensation - Addi

Stock Based Compensation - Additional Information (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock option expense	$ 46,000	$ 36,000
Amortization of non-vested stock grants and performance-based awards	$ 1,866,000	$ 1,612,000
Stock options exercised by employees and directors	0	9,500
Number of shares of non-vested stock that vested	7,185	5,234

Investment in Storage Facilit35

Investment in Storage Facilities - Summary of Activity in Storage Facilities (Detail) $ in Thousands	3 Months Ended
	Mar. 31, 2016USD ($)
Cost:
Beginning balance	$ 2,491,702
Acquisition of storage facilities	327,408
Improvements and equipment additions	6,651
Additions to consolidated subsidiary	1,815
Net increase in construction in progress	6,106
Dispositions	(696)
Ending balance	2,832,986
Accumulated Depreciation:
Beginning balance	465,195
Additions during the period	15,255
Dispositions	(591)
Ending balance	$ 479,859

Investment in Storage Facilit36

Investment in Storage Facilities - Additional Information (Detail) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2016USD ($)FacilityPropertyStore	Mar. 31, 2015USD ($)	Dec. 31, 2015USD ($)Property
Investment Holdings [Line Items]
Number of storage facilities acquired | Facility	25
Stores acquired at certificate of occupancy | Store	1
Cash paid for properties acquired	$ 326,000
Deposits paid at the time of contract			$ 2,500
Acquisition costs	2,384	$ 582
Issuance of Operating Partnership Units	$ 4,500
Amortization period for in-place customer leases on a straight-line basis	12 months
Amortization expense related to in-place customer leases	$ 1,200	1,000
Amortization expense expected for 2016	5,200
Amortization expense expected for 2017	$ 500
Net proceeds from the sale of storage facilities		711
(Loss) gain on sale of storage facilities		$ (7)
Acquisitions 2016 [Member]
Investment Holdings [Line Items]
Number of storage facilities acquired | Property	25
Cash paid for properties acquired	$ 326,048
Acquisition costs	$ 2,384		$ 345
Property Dispositions [Member]
Investment Holdings [Line Items]
Number of properties sold | Property			3
Carrying value of properties sold			$ 5,100
Net proceeds from the sale of storage facilities			4,600
(Loss) gain on sale of storage facilities			$ (500)

Investment in Storage Facilit37

Investment in Storage Facilities - Schedule of Acquired Facilities and Purchase Price of Facilities (Detail) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2016USD ($)FacilityProperty	Mar. 31, 2015USD ($)	Dec. 31, 2015USD ($)
Investment Holdings [Line Items]
Number of Properties | Facility	25
Cash Paid	$ 326,000
Closing Costs Expensed	$ 2,384	$ 582
Acquisitions 2016 [Member]
Investment Holdings [Line Items]
Number of Properties | Property	25
Purchase Price	$ 331,801
Cash Paid	326,048
Consideration paid Value of Operating Partnership Units Issued	4,472
Net Other Liabilities (Assets) Assumed	1,281
Land	114,738
Acquisition Date Building, Equipment, and Improvements	212,670
Fair Value In-Place Customer Leases	4,393
Closing Costs Expensed	$ 2,384		$ 345
Florida [Member] | Date Of Acquisition, 1/6/2016 [Member]
Investment Holdings [Line Items]
Number of Properties | Property	4
Date of Acquisition	Jan. 6, 2016
Purchase Price	$ 20,350
Cash Paid	20,246
Net Other Liabilities (Assets) Assumed	104
Land	6,646
Acquisition Date Building, Equipment, and Improvements	13,339
Fair Value In-Place Customer Leases	365
Closing Costs Expensed	$ 366
Florida [Member] | Date Of Acquisition, 2/12/2016 [Member]
Investment Holdings [Line Items]
Number of Properties | Property	1
Date of Acquisition	Feb. 12, 2016
Purchase Price	$ 11,274
Cash Paid	11,270
Net Other Liabilities (Assets) Assumed	4
Land	2,294
Acquisition Date Building, Equipment, and Improvements	$ 8,980
California [Member] | Date Of Acquisition, 1/21/2016 [Member]
Investment Holdings [Line Items]
Number of Properties | Property	4
Date of Acquisition	Jan. 21, 2016
Purchase Price	$ 78,750
Cash Paid	78,562
Net Other Liabilities (Assets) Assumed	188
Land	27,876
Acquisition Date Building, Equipment, and Improvements	49,860
Fair Value In-Place Customer Leases	1,014
Closing Costs Expensed	$ 327
California [Member] | Date Of Acquisition, 3/16/2016 [Member]
Investment Holdings [Line Items]
Number of Properties | Property	3
Date of Acquisition	Mar. 16, 2016
Purchase Price	$ 68,832
Cash Paid	63,965
Consideration paid Value of Operating Partnership Units Issued	4,472
Net Other Liabilities (Assets) Assumed	395
Land	22,647
Acquisition Date Building, Equipment, and Improvements	45,371
Fair Value In-Place Customer Leases	814
Closing Costs Expensed	$ 260
California [Member] | Date Of Acquisition, 3/17/2016 [Member]
Investment Holdings [Line Items]
Number of Properties | Property	1
Date of Acquisition	Mar. 17, 2016
Purchase Price	$ 17,320
Cash Paid	17,278
Net Other Liabilities (Assets) Assumed	42
Land	6,728
Acquisition Date Building, Equipment, and Improvements	10,339
Fair Value In-Place Customer Leases	253
Closing Costs Expensed	$ 115
New Hampshire [Member] | Date Of Acquisition, 1/21/2016 [Member]
Investment Holdings [Line Items]
Number of Properties | Property	5
Date of Acquisition	Jan. 21, 2016
Purchase Price	$ 54,225
Cash Paid	53,941
Net Other Liabilities (Assets) Assumed	284
Land	12,902
Acquisition Date Building, Equipment, and Improvements	40,428
Fair Value In-Place Customer Leases	895
Closing Costs Expensed	$ 569
Massachusetts [Member] | Date Of Acquisition, 1/21/2016 [Member]
Investment Holdings [Line Items]
Number of Properties | Property	1
Date of Acquisition	Jan. 21, 2016
Purchase Price	$ 11,375
Cash Paid	11,350
Net Other Liabilities (Assets) Assumed	25
Land	4,874
Acquisition Date Building, Equipment, and Improvements	6,335
Fair Value In-Place Customer Leases	166
Closing Costs Expensed	$ 64
Texas [Member] | Date Of Acquisition, 1/21/2016 [Member]
Investment Holdings [Line Items]
Number of Properties | Property	3
Date of Acquisition	Jan. 21, 2016
Purchase Price	$ 42,050
Cash Paid	41,894
Net Other Liabilities (Assets) Assumed	156
Land	23,487
Acquisition Date Building, Equipment, and Improvements	18,000
Fair Value In-Place Customer Leases	563
Closing Costs Expensed	$ 247
Arizona [Member] | Date Of Acquisition, 2/1/2016 [Member]
Investment Holdings [Line Items]
Number of Properties | Property	1
Date of Acquisition	Feb. 1, 2016
Purchase Price	$ 9,275
Cash Paid	9,261
Net Other Liabilities (Assets) Assumed	14
Land	988
Acquisition Date Building, Equipment, and Improvements	8,224
Fair Value In-Place Customer Leases	63
Closing Costs Expensed	$ 119
Pennsylvania [Member] | Date Of Acquisition, 2/17/2016[Member]
Investment Holdings [Line Items]
Number of Properties | Property	1
Date of Acquisition	Feb. 17, 2016
Purchase Price	$ 5,750
Cash Paid	5,732
Net Other Liabilities (Assets) Assumed	18
Land	1,768
Acquisition Date Building, Equipment, and Improvements	3,879
Fair Value In-Place Customer Leases	103
Closing Costs Expensed	$ 147
Colorado [Member] | Date Of Acquisition, 2/29/2016 [Member]
Investment Holdings [Line Items]
Number of Properties | Property	1
Date of Acquisition	Feb. 29, 2016
Purchase Price	$ 12,600
Cash Paid	12,549
Net Other Liabilities (Assets) Assumed	51
Land	4,528
Acquisition Date Building, Equipment, and Improvements	7,915
Fair Value In-Place Customer Leases	157
Closing Costs Expensed	$ 170

Investment in Storage Facilit38

Investment in Storage Facilities - Schedule of Fair Value of In-Place Customer Lease Intangible Assets (Detail) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Real Estate [Abstract]
In-place customer leases	$ 26,714	$ 22,320
Accumulated amortization	(22,192)	(21,017)
Net carrying value at the end of period	$ 4,522	$ 1,303

Investment in Storage Facilit39

Investment in Storage Facilities - Pro Forma Information Based on Combined Historical Financial Statements on Properties Acquired (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Investments Schedule [Abstract]
Total revenues	$ 101,551	$ 90,871
Net income attributable to common shareholders	$ 31,745	$ 20,173
Basic	$ 0.81	$ 0.52
Diluted	$ 0.81	$ 0.51

Investment in Storage Facilit40

Investment in Storage Facilities - Summary of Revenues and Earnings Related to Properties Included in Company's Consolidated Statements of Operations (Detail) - Acquisitions 2016 [Member] $ in Thousands	3 Months Ended
	Mar. 31, 2016USD ($)
Business Combination, Separately Recognized Transactions [Line Items]
Total revenues	$ 3,754
Net loss attributable to common shareholders	$ (1,760)

Investment in Storage Facilit41

Investment in Storage Facilities - Summary of Revenues and Expenses Related to Sale of Properties Included in Company's Consolidated Statements of Operations (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total revenues	$ 99,124	$ 85,408
Property operations and maintenance expense	(22,861)	(20,559)
Real estate tax expense	(10,547)	(8,920)
Depreciation and amortization expense	$ (16,425)	(14,181)
Loss on sale of storage facilities		(7)
Properties Sold In Two Thousand And Fifteen Member
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total revenues		40
Property operations and maintenance expense		(16)
Real estate tax expense		(5)
Depreciation and amortization expense		(9)
Loss on sale of storage facilities		(7)
Total income from discontinued operations		$ 3

Unsecured Line of Credit and 42

Unsecured Line of Credit and Term Notes - Borrowings Outstanding on Unsecured Line of Credit and Term Notes (Detail) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Unsecured Line Of Credit And Term Notes [Line Items]
Revolving line of credit borrowings	$ 141,000	$ 79,000
Total term notes payable	750,000	750,000
Term Note Due April 26, 2016 [Member]
Unsecured Line Of Credit And Term Notes [Line Items]
Total term notes payable	150,000	150,000
Term Note Due June 4, 2020 [Member]
Unsecured Line Of Credit And Term Notes [Line Items]
Total term notes payable	325,000	325,000
Term Note Due August 5, 2021 [Member]
Unsecured Line Of Credit And Term Notes [Line Items]
Total term notes payable	100,000	100,000
Term Note Due April 8, 2024 [Member]
Unsecured Line Of Credit And Term Notes [Line Items]
Total term notes payable	$ 175,000	$ 175,000

Unsecured Line of Credit and 43

Unsecured Line of Credit and Term Notes - Additional Information (Detail) - USD ($)	Apr. 08, 2014	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2011	Jan. 31, 2016	Dec. 31, 2015
Unsecured Line Of Credit And Term Notes [Line Items]
Unsecured term note		$ 750,000,000				$ 750,000,000
Debt issuance costs		3,200,000	$ 3,400,000
Revolving Credit Facility [Member]
Unsecured Line Of Credit And Term Notes [Line Items]
Revolving credit limit		$ 500,000,000			$ 300,000,000
Maturity on June 4, 2020 [Member]
Unsecured Line Of Credit And Term Notes [Line Items]
Basis spread over LIBOR		1.15%
Unsecured term note		$ 325,000,000
Maturity on December 10, 2019 [Member]
Unsecured Line Of Credit And Term Notes [Line Items]
Basis spread over LIBOR		1.10%
Facility fee		0.15%
Interest rate, line of credit facility		1.53%				1.72%
Amount available on unsecured line of credit		$ 359,000,000
Line of credit facility, expiration date		Dec. 10, 2019
Maturity in April, 2024 [Member]
Unsecured Line Of Credit And Term Notes [Line Items]
Line of credit facility, expiration date		Apr. 8, 2024
Additional secured term note	$ 175,000,000
Term note stated interest rate		4.533%
Increase in interest rate on term loan		6.283%
Repayment of Lines of Credit	$ 115,000,000
Maturity in August 2021 [Member]
Unsecured Line Of Credit And Term Notes [Line Items]
Line of credit facility, expiration date		Aug. 5, 2021
Additional secured term note				$ 100,000,000
Term note stated interest rate				5.54%
Increase in interest rate on term loan				7.29%
Maturity in April 2016 [Member]
Unsecured Line Of Credit And Term Notes [Line Items]
Unsecured term note		$ 150,000,000
Line of credit facility, expiration date		Apr. 26, 2016
Term note stated interest rate		6.38%
Increase in interest rate on term loan		8.13%

Mortgages Payable and Debt Ma44

Mortgages Payable and Debt Maturities - Summary of Mortgage Payable (Detail) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Mortgages payable	$ 1,959	$ 1,993
5.99% Mortgage Notes Due May 1, 2026 [Member]
Debt Instrument [Line Items]
Mortgages payable	$ 1,959	$ 1,993

Mortgages Payable and Debt Ma45

Mortgages Payable and Debt Maturities - Summary of Mortgage Payable (Parenthetical) (Detail) - 5.99% Mortgage Notes Due May 1, 2026 [Member] $ in Millions	3 Months Ended
	Mar. 31, 2016USD ($)Facility
Debt Instrument [Line Items]
Interest rate	5.99%
Mortgage note due date	May 1, 2026
Self-storage facilities | Facility	1
Aggregate net book value of property pledged for mortgage note | $	$ 4.3
Effective interest rate	6.24%

Mortgages Payable and Debt Ma46

Mortgages Payable and Debt Maturities - Summary of Debt Obligation and Interest Rate Derivatives (Detail) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Line of credit	$ 141,000	$ 79,000
Term notes	750,000	750,000
Mortgage note, total	1,959	1,993
Interest rate derivatives - liability	26,846	$ 15,343
Line of Credit - Variable Rate LIBOR + 1.10% (1.53% at March 31, 2016) [Member]
Debt Instrument [Line Items]
Payable due 2019	141,000
Line of credit	141,000
Debt instrument, fair value	141,000
Term Note - Fixed Rate 6.38% [Member]
Debt Instrument [Line Items]
Payable due 2016	150,000
Term notes	150,000
Term note, fair value	153,184
Term Note - Variable Rate LIBOR+1.15% (1.59% at March 31, 2016) [Member]
Debt Instrument [Line Items]
Payable due 2020	325,000
Term notes	325,000
Term note, fair value	325,000
Term Note - Fixed Rate 5.54% [Member]
Debt Instrument [Line Items]
Payables due Thereafter	100,000
Term notes	100,000
Term note, fair value	112,467
Term Note - Fixed Rate 4.533% [Member]
Debt Instrument [Line Items]
Payables due Thereafter	175,000
Term notes	175,000
Term note, fair value	186,337
Mortgage Note - Fixed Rate 5.99% [Member]
Debt Instrument [Line Items]
Payable due 2016	108
Payables due 2017	151
Payables due 2018	160
Payable due 2019	170
Payable due 2020	181
Payables due Thereafter	1,189
Mortgage note, total	1,959
Debt instrument, fair value	$ 2,096

Mortgages Payable and Debt Ma47

Mortgages Payable and Debt Maturities - Summary of Debt Obligation and Interest Rate Derivatives (Parenthetical) (Detail)	3 Months Ended
	Mar. 31, 2016
Line of Credit - Variable Rate LIBOR + 1.10% (1.53% at March 31, 2016) [Member]
Debt Instrument [Line Items]
Interest rate at end of period	1.53%
Basis spread over LIBOR	1.10%
Term Note - Fixed Rate 6.38% [Member]
Debt Instrument [Line Items]
Interest rate	6.38%
Term Note - Variable Rate LIBOR+1.15% (1.59% at March 31, 2016) [Member]
Debt Instrument [Line Items]
Interest rate	1.59%
Basis spread over LIBOR	1.15%
Term Note - Fixed Rate 5.54% [Member]
Debt Instrument [Line Items]
Interest rate	5.54%
Term Note - Fixed Rate 4.533% [Member]
Debt Instrument [Line Items]
Interest rate	4.533%
Mortgage Note - Fixed Rate 5.99% [Member]
Debt Instrument [Line Items]
Interest rate	5.99%

Derivative Financial Instrume48

Derivative Financial Instruments - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2017	Dec. 31, 2015
Derivative [Line Items]
Realized loss reclassified from accumulated other comprehensive loss to interest expense	$ (1,197)	$ (1,358)
Fair value of interest rate swap agreements, liability	26,846			$ 15,343
Fair value of interest rate swap agreements, asset				$ 550
Net termination cost	26,800
Interest Expense [Member]
Derivative [Line Items]
Realized loss reclassified from accumulated other comprehensive loss to interest expense	1,200	$ 1,400
Scenario, Forecast [Member]
Derivative [Line Items]
Estimated payments to be made under interest rate swaps			$ 10,800
Interest Rate Swap [Member]
Derivative [Line Items]
Notional amount of variable rate debt swapped	325,000
Notional pre-issuance swap agreement	$ 150,000
Pre-Issuance Swap [Member]
Derivative [Line Items]
Debt issuance date	May 31, 2016

Derivative Financial Instrume49

Derivative Financial Instruments - Summary of Interest Rate Swap Agreements (Detail)	3 Months Ended
	Mar. 31, 2016USD ($)
Interest Rate Swap [Member]
Derivative [Line Items]
Notional Amount	$ 125,000,000
Effective Date	Sep. 1, 2011
Expiration Date	Aug. 1, 2018
Fixed Rate Paid	2.37%
Interest Rate Swap [Member] | London Interbank Offered Rate (LIBOR) [Member]
Derivative [Line Items]
Floating Rate Received	1 month LIBOR
Interest Rate Swap One [Member]
Derivative [Line Items]
Notional Amount	$ 100,000,000
Effective Date	Dec. 30, 2011
Expiration Date	Dec. 29, 2017
Fixed Rate Paid	1.6125%
Interest Rate Swap One [Member] | London Interbank Offered Rate (LIBOR) [Member]
Derivative [Line Items]
Floating Rate Received	1 month LIBOR
Interest Rate Swap Two [Member]
Derivative [Line Items]
Notional Amount	$ 100,000,000
Effective Date	Sep. 4, 2013
Expiration Date	Sep. 4, 2018
Fixed Rate Paid	1.371%
Interest Rate Swap Two [Member] | London Interbank Offered Rate (LIBOR) [Member]
Derivative [Line Items]
Floating Rate Received	1 month LIBOR
Interest Rate Swap Three [Member]
Derivative [Line Items]
Notional Amount	$ 100,000,000
Effective Date	Dec. 29, 2017
Expiration Date	Nov. 29, 2019
Fixed Rate Paid	3.968%
Interest Rate Swap Three [Member] | London Interbank Offered Rate (LIBOR) [Member]
Derivative [Line Items]
Floating Rate Received	1 month LIBOR
Interest Rate Swap Four [Member]
Derivative [Line Items]
Notional Amount	$ 125,000,000
Effective Date	Aug. 1, 2018
Expiration Date	Jun. 1, 2020
Fixed Rate Paid	4.193%
Interest Rate Swap Four [Member] | London Interbank Offered Rate (LIBOR) [Member]
Derivative [Line Items]
Floating Rate Received	1 month LIBOR
Interest Rate Swap Five [Member]
Derivative [Line Items]
Notional Amount	$ 50,000,000
Effective Date	May 31, 2016
Expiration Date	May 31, 2026
Fixed Rate Paid	2.156%
Interest Rate Swap Five [Member] | London Interbank Offered Rate (LIBOR) [Member]
Derivative [Line Items]
Floating Rate Received	3 month LIBOR
Interest Rate Swap Six [Member]
Derivative [Line Items]
Notional Amount	$ 50,000,000
Effective Date	May 31, 2016
Expiration Date	May 31, 2026
Fixed Rate Paid	2.1875%
Interest Rate Swap Six [Member] | London Interbank Offered Rate (LIBOR) [Member]
Derivative [Line Items]
Floating Rate Received	3 month LIBOR
Interest Rate Swap Seven [Member]
Derivative [Line Items]
Notional Amount	$ 25,000,000
Effective Date	May 31, 2016
Expiration Date	May 31, 2026
Fixed Rate Paid	2.033%
Interest Rate Swap Seven [Member] | London Interbank Offered Rate (LIBOR) [Member]
Derivative [Line Items]
Floating Rate Received	3 month LIBOR
Interest Rate Swap Eight [Member]
Derivative [Line Items]
Notional Amount	$ 25,000,000
Effective Date	May 31, 2016
Expiration Date	May 31, 2026
Fixed Rate Paid	1.939%
Interest Rate Swap Eight [Member] | London Interbank Offered Rate (LIBOR) [Member]
Derivative [Line Items]
Floating Rate Received	3 month LIBOR

Derivative Financial Instrume50

Derivative Financial Instruments - Summary of Changes in AOCL (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Accumulated other comprehensive loss beginning of period	$ (14,415)	$ (13,005)
Realized loss reclassified from accumulated other comprehensive loss to interest expense	1,197	1,358
Unrealized loss from changes in the fair value of the effective portion of the interest rate swaps	(13,293)	(5,345)
Loss included in other comprehensive loss	(12,096)	(3,987)
Accumulated other comprehensive loss end of period	$ (26,511)	$ (16,992)

Fair Value Measurements - Asset

Fair Value Measurements - Assets and Liabilities Carried at Fair Value Measured on Recurring Basis (Detail) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Interest rate swaps, Asset		$ 550
Interest rate swaps, Liability	$ (26,846)	(15,343)
Interest Rate Swap [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Interest rate swaps, Asset		550
Interest rate swaps, Liability	(26,846)	(15,343)
Interest Rate Swap [Member] | Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Interest rate swaps, Asset		550
Interest rate swaps, Liability	$ (26,846)	$ (15,343)

Fair Value Measurements - Addit

Fair Value Measurements - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2016Facility
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Number of storage facilities acquired	25
Storage Facilities [Member]
Fair Value Assets And Liabilities Measured On Recurring Basis [Line Items]
Number of storage facilities acquired	25

Investment in Joint Ventures -

Investment in Joint Ventures - Additional Information (Detail)	3 Months Ended		12 Months Ended
	Mar. 31, 2016USD ($)Property	Mar. 31, 2015USD ($)	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)Property	Dec. 31, 2013USD ($)	Dec. 31, 2012USD ($)Property	Dec. 31, 2011USD ($)Property	Dec. 31, 2008USD ($)Property
Schedule of Equity Method Investments [Line Items]
Investment at carrying value	$ 64,985,000		$ 62,520,000
Equity in income of joint ventures	$ 915,000	$ 646,000
Sovran HHF Storage Holdings LLC [Member]
Schedule of Equity Method Investments [Line Items]
Percentage ownership in unconsolidated joint venture	20.00%
Investment at carrying value	$ 44,300,000		44,600,000
Payment for property acquisition				$ 187,200,000				$ 171,500,000
Number of properties owned and managed under twenty-percent stake joint venture | Property	39							25
Additional number of properties owned and managed under twenty-percent stake joint venture | Property				14
Contribution of company to joint venture as share in capital				$ 28,600,000		$ 1,200,000		$ 18,600,000
Receipt of return of capital distribution					$ 3,400,000
Excess of investment over net asset due to capitalization of acquisition related costs	$ 1,700,000
Other-than-temporary impairment recorded on investment	0
Sovran HHF Storage Holdings LLC [Member] | Acquisitions 2014 [Member]
Schedule of Equity Method Investments [Line Items]
Contribution of company to joint venture as share in capital			400,000
Sovran HHF Storage Holdings II LLC [Member]
Schedule of Equity Method Investments [Line Items]
Investment at carrying value	$ 13,900,000		13,900,000
Payment for property acquisition						29,000,000	$ 166,100,000
Contribution of company to joint venture as share in capital			1,700,000			$ 2,400,000	$ 12,800,000
Percentage of variable interest ownership in unconsolidated joint venture	15.00%
Number of properties owned and managed under fifteen-percent stake joint venture | Property	30					10	20
Sovran HHF and Sovran HHF II [Member]
Schedule of Equity Method Investments [Line Items]
Management and call center fee as a percentage of revenues	7.00%
Management and call center fee earned	$ 1,200,000	1,200,000
Equity in income of joint ventures	$ 800,000	600,000
Urban Box Coralway Storage, LLC [Member]
Schedule of Equity Method Investments [Line Items]
Percentage ownership in unconsolidated joint venture	85.00%
Contribution of company to joint venture as share in capital			4,000,000
Management and call center fee as a percentage of revenues	6.00%
Management and call center fee earned	$ 0		0
Iskalo Office Holdings, LLC [Member]
Schedule of Equity Method Investments [Line Items]
Percentage ownership in unconsolidated joint venture	49.00%
Equity in income of joint ventures	$ 59,000	58,000
Investment liability at carrying value	(500,000)		(500,000)
Rent paid during the period	$ 300,000	$ 300,000
SNL/Orix 1200 McDonald Ave., LLC [Member]
Schedule of Equity Method Investments [Line Items]
Percentage ownership in unconsolidated joint venture	5.00%
Management and call center fee earned	$ 0		$ 0
SNL/Orix 1200 McDonald Ave., LLC [Member] | Common Stock Shares [Member]
Schedule of Equity Method Investments [Line Items]
Contribution of company to joint venture as share in capital	400,000
SNL/Orix 1200 McDonald Ave., LLC [Member] | Preferred Stock [Member]
Schedule of Equity Method Investments [Line Items]
Contribution of company to joint venture as share in capital	$ 2,300,000

Investment in Joint Ventures 54

Investment in Joint Ventures - Summary of Unconsolidated Joint Ventures' Financial Statements (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Schedule of Equity Method Investments [Line Items]
Investment in storage facilities, net	$ 2,353,127		$ 2,026,507
Other assets	12,900		9,048
Total Assets	2,449,483		2,118,822
Mortgages payable	1,959		1,993
Total Liabilities	962,839		898,336
Unaffiliated partners' equity	428
Company equity	1,462,003		1,202,315
Total Partners' Equity	1,462,431		$ 1,202,315
Depreciation and amortization of customer list	(16,425)	$ (14,181)
Amortization of financing fees	(356)	(296)
Income tax expense	(600)	(400)
Interest expense	(9,134)	$ (9,161)
Unconsolidated Joint Ventures [Member]
Schedule of Equity Method Investments [Line Items]
Investment in storage facilities, net	527,662
Investment in office building	5,007
Other assets	17,238
Total Assets	549,907
Due to the Company	672
Mortgages payable	223,401
Other liabilities	6,006
Total Liabilities	230,079
Unaffiliated partners' equity	257,098
Company equity	62,730
Total Partners' Equity	319,828
Total Liabilities and Partners' Equity (Deficiency)	549,907
Total revenues	18,005
Property operating expenses	(5,951)
Administrative, management and call center fees	(1,303)
Depreciation and amortization of customer list	(3,106)
Amortization of financing fees	(89)
Income tax expense	(58)
Interest expense	(2,574)
Net income	$ 4,924

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Schedule Of Income Taxes [Line Items]
Federal and state income tax expense	$ 600,000	$ 400,000
Unrecognized tax benefits	0	0
Interest or penalties related to uncertain tax positions	0	$ 0
Current prepaid taxes	100,000
Deferred tax liability	$ 1,300,000
Tax Year 2013 [Member]
Schedule Of Income Taxes [Line Items]
Tax years open to examination	2,013
Latest Tax Year [Member]
Schedule Of Income Taxes [Line Items]
Tax years open to examination	2,015

Earnings Per Share - Computatio

Earnings Per Share - Computation of Basic and Diluted Earnings Per Common Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Numerator:
Net income attributable to common shareholders	$ 28,339	$ 22,451
Denominator:
Denominator for basic earnings per share - weighted average shares	38,410,817	34,329,768
Effect of Dilutive Securities:
Stock options and non-vested stock	252,000	225,000
Denominator for diluted earnings per share - adjusted weighted average shares and assumed conversion	38,663,138	34,554,871
Basic earnings per common share attributable to common shareholders	$ 0.74	$ 0.65
Diluted earnings per common share attributable to common shareholders	$ 0.73	$ 0.65

Earnings Per Share - Additional

Earnings Per Share - Additional Information (Detail) - shares	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Restricted Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Securities not included in the effect of dilutive securities	130,573	171,220

Shareholders' Equity - Reconcil

Shareholders' Equity - Reconciliation of Changes in Total Shareholders' Equity (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Equity [Abstract]
Beginning balance	$ 1,202,315
Net proceeds from the issuance of common stock	274,298
Exercise of stock options	0
Earned portion of non-vested stock	1,866
Stock option expense	46	$ 36
Deferred compensation - directors	23
Adjustment to redemption value on noncontrolling redeemable Operating Partnership units	(1,584)
Net income attributable to common shareholders	28,339	22,451
Change in fair value of derivatives	(12,096)	$ (3,987)
Dividends	(31,204)
Ending balance	$ 1,462,003

Shareholders' Equity - Addition

Shareholders' Equity - Additional Information (Detail) - USD ($)	Jan. 20, 2016	Mar. 31, 2016	May. 12, 2014
Stockholders Equity [Line Items]
Common stock shares issued under equity offering program	2,645,000
Common stock, price per share, public offering	$ 105.75
Proceeds from issuance of common stock	$ 269,700,000
Common stock value authorized under equity offering program			$ 225,000,000
Shares issued under dividend reinvestment plan		44,018
Equity Program [Member]
Stockholders Equity [Line Items]
Common stock, value reserved for future issuance		$ 59,300,000

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) $ in Millions	Apr. 26, 2016Facility	May. 02, 2016USD ($)Facility	Apr. 13, 2016Facility	Mar. 31, 2016USD ($)Facility
Commitment And Contingencies [Line Items]
Payment for self-storage facilities under contract | $				$ 146.4
Number of self-storage facilities under contract to be purchased				13
Subsequent Event [Member] | Acquisition 2016 [Member]
Commitment And Contingencies [Line Items]
Payment for self-storage facilities under contract | $		$ 86.7
Number of self-storage facilities under contract to be purchased			8
Number of self-storage facilities under contract to be purchased	6	6

Subsequent Events - Additional

Subsequent Events - Additional Information (Detail) $ / shares in Units, $ in Thousands	Apr. 26, 2016USD ($)Facility	Apr. 13, 2016USD ($)Facility	May. 02, 2016Facility	Mar. 31, 2016USD ($)Facility	Apr. 01, 2016$ / shares	Dec. 31, 2015USD ($)
Subsequent Event [Line Items]
Dividend declared, date				Apr. 1, 2016
Dividend paid, date				Apr. 26, 2016
Dividend record, date				Apr. 14, 2016
Line of credit balance outstanding after funding of six acquisitions				$ 141,000		$ 79,000
Number of self-storage facilities under contract to be sold | Facility				13
Subsequent Event [Member]
Subsequent Event [Line Items]
Dividend per common share | $ / shares					$ 0.95
Dividend paid	$ 37,300
Repayment of outstanding balance of Notes	$ 150,000
Subsequent Event [Member] | Acquisition 2016 [Member]
Subsequent Event [Line Items]
Number of self-storage facilities under contract to be purchased | Facility	6		6
Line of credit balance outstanding after funding of six acquisitions	$ 390,000
Number of self-storage facilities under contract to be sold | Facility		8
Sale Price Of Facility		$ 35,000