National Storage Affiliates Trust (NSA) 10-Q 2 Aug 19 2019 Q2 Quarterly report Financial data

COVER PAGE

COVER PAGE - shares	6 Months Ended
	Jun. 30, 2019	Aug. 01, 2019
Entity Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jun. 30, 2019
Document Transition Report	false
Entity File Number	001-37351
Entity Registrant Name	National Storage Affiliates Trust
Entity Central Index Key	0001618563
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q2
Amendment Flag	false
Entity Incorporation, State or Country Code	MD
Entity Tax Identification Number	46-5053858
Entity Address, Address Line One	8400 East Prentice Avenue, 9th Floor
Entity Address, City or Town	Greenwood Village
Entity Address, State or Province	CO
Entity Address, Postal Zip Code	80111
City Area Code	720
Local Phone Number	630-2600
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		59,296,248
Common Shares of Beneficial Interest, $0.01 par value per share
Entity Information [Line Items]
Title of 12(b) Security	Common Shares of Beneficial Interest, $0.01 par value per share
Trading Symbol	NSA
Security Exchange Name	NYSE
Series A Cumulative Redeemable Preferred Shares of Beneficial Interest, par value $0.01 per share
Entity Information [Line Items]
Title of 12(b) Security	Series A Cumulative Redeemable Preferred Shares of Beneficial Interest, par value $0.01 per share
Trading Symbol	NSA Pr A
Security Exchange Name	NYSE

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Real estate
Self storage properties	$ 3,015,549	$ 2,637,723
Less accumulated depreciation	(289,886)	(246,261)
Self storage properties, net	2,725,663	2,391,462
Cash and cash equivalents	15,255	13,181
Restricted cash	4,498	3,182
Debt issuance costs, net	810	1,260
Investment in unconsolidated real estate ventures	233,295	245,125
Other assets, net	59,363	75,053
Operating lease right-of-use assets	22,971	0
Total assets	3,061,855	2,729,263
Liabilities
Debt financing	1,469,647	1,278,102
Accounts payable and accrued liabilities	53,054	33,130
Operating lease liabilities	24,152	0
Deferred revenue	16,218	15,732
Total liabilities	1,563,071	1,326,964
Commitments and contingencies (Note 11)
Equity
Preferred shares of beneficial interest, par value $0.01 per share. 50,000,000 authorized, 8,685,680 and 6,900,000 issued and outstanding at June 30, 2019 and December 31, 2018, respectively, at liquidation preference	217,142	172,500
Common shares of beneficial interest, par value $0.01 per share. 250,000,000 shares authorized, 59,296,969 and 56,654,009 shares issued and outstanding at June 30, 2019 and December 31, 2018, respectively	593	567
Additional paid-in capital	901,499	844,276
Distributions in excess of earnings	(156,192)	(114,122)
Accumulated other comprehensive (loss) income	(5,466)	13,618
Total shareholders' equity	957,576	916,839
Noncontrolling interests	541,208	485,460
Total equity	1,498,784	1,402,299
Total liabilities and equity	$ 3,061,855	$ 2,729,263

CONDENSED CONSOLIDATED BALANC_2

CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) (Parenthetical) - $ / shares	Jun. 30, 2019	Dec. 31, 2018
Statement of Financial Position [Abstract]
Series A Preferred shares of beneficial interest, par value (in dollars per share)	$ 0.01	$ 0.01
Series A Preferred shares of beneficial interest, authorized (in shares)	50,000,000	50,000,000
Series A Preferred shares of beneficial interest, issued (in shares)	8,685,680	6,900,000
Series A Preferred shares of beneficial interest, outstanding (in shares)	8,685,680	6,900,000
Common shares of beneficial interest, par value (in dollars per share)	$ 0.01	$ 0.01
Common shares of beneficial interest, authorized (in shares)	250,000,000	250,000,000
Common shares of beneficial interest, issued (in shares)	59,296,969	56,654,009
Common shares of beneficial interest, outstanding (in shares)	59,296,969	56,654,009

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
REVENUE
Rental revenue	$ 87,175	$ 75,019	$ 170,030	$ 147,030
Total revenue	95,419	79,723	185,991	156,216
OPERATING EXPENSES
Property operating expenses	27,190	25,184	53,647	50,410
General and administrative expenses	11,170	8,460	21,936	16,766
Depreciation and amortization	25,829	22,389	50,178	43,757
Total operating expenses	64,189	56,033	125,761	110,933
OTHER (EXPENSE) INCOME
Interest expense	(13,947)	(10,472)	(27,158)	(20,107)
Equity in (losses) earnings of unconsolidated real estate ventures	(1,646)	100	(3,748)	48
Acquisition costs	(305)	(150)	(462)	(330)
Non-operating expense	(169)	0	(267)	(84)
Gain (loss) on sale of self storage properties	2,814	(83)	2,814	391
Other expense	(13,253)	(10,605)	(28,821)	(20,082)
Income before income taxes	17,977	13,085	31,409	25,201
Income tax expense	(244)	(44)	(736)	(187)
Net income	17,733	13,041	30,673	25,014
Net income attributable to noncontrolling interests	(25,389)	(7,150)	(30,918)	(8,663)
Net (loss) income attributable to National Storage Affiliates Trust	(7,656)	5,891	(245)	16,351
Distributions to preferred shareholders	(3,257)	(2,587)	(5,845)	(5,175)
Net Income (Loss) Available to Common Stockholders, Basic	$ (10,913)	$ 3,304	$ (6,090)	$ 11,176
Earnings (loss) per common share - basic and diluted
Earnings (loss) per share - basic	$ (0.19)	$ 0.07	$ (0.11)	$ 0.22
Earnings (loss) per share - diluted	$ (0.19)	$ 0.07	$ (0.11)	$ 0.19
Weighted average shares outstanding - basic	57,543	50,486	57,101	50,393
Weighted average shares outstanding - diluted	57,543	50,486	57,101	100,492
Dividends declared per common share	$ 0.32	$ 0.29	$ 0.62	$ 0.57
Other property-related revenue
REVENUE
Revenue	$ 3,128	$ 2,549	$ 5,952	$ 4,870
Management fees and other revenue
REVENUE
Revenue	$ 5,116	$ 2,155	$ 10,009	$ 4,316

CONDENSED CONSOLIDATED STATEM_2

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Statement of Comprehensive Income [Abstract]
Net income	$ 17,733	$ 13,041	$ 30,673	$ 25,014
Other comprehensive (loss) income
Unrealized (loss) gain on derivative contracts	(19,075)	4,665	(27,114)	13,655
Reclassification of other comprehensive income to interest expense	(1,277)	(281)	(2,553)	(232)
Other comprehensive (loss) income	(20,352)	4,384	(29,667)	13,423
Comprehensive (loss) income	(2,619)	17,425	1,006	38,437
Comprehensive income attributable to noncontrolling interests	(18,029)	(8,834)	(20,160)	(13,838)
Comprehensive (loss) income attributable to National Storage Affiliates Trust	$ (20,648)	$ 8,591	$ (19,154)	$ 24,599

CONDENSED CONSOLIDATED STATEM_3

CONDENSED CONSOLIDATED STATEMENT OF CHANGES IN EQUITY (Unaudited) - USD ($) $ in Thousands	Total	Series A-1 preferred units, OP units, and subordinated performance units	OP units	Preferred Shares	Common Shares	Additional Paid-in Capital	Distributions In Excess Of Earnings	Accumulated Other Comprehensive Income	Noncontrolling Interests	Noncontrolling InterestsSeries A-1 preferred units, OP units, and subordinated performance units	Noncontrolling InterestsOP units	Redeemable Preferred Stock	Redeemable Preferred StockPreferred Shares	Redeemable Preferred StockAdditional Paid-in Capital	Common Shares of Beneficial Interest, $0.01 par value per share	Common Shares of Beneficial Interest, $0.01 par value per shareCommon Shares	Common Shares of Beneficial Interest, $0.01 par value per shareAdditional Paid-in Capital
Balances (in shares) at Dec. 31, 2017				6,900,000
Balances (in shares) at Dec. 31, 2017					50,284,934
Balances at Dec. 31, 2017	$ 1,271,487			$ 172,500	$ 503	$ 711,467	$ (55,729)	$ 12,282	$ 430,464
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of equity units		$ 22,403	$ 5							$ 22,403	$ 5
Redemptions of OP units (in shares)					145,334
Redemptions of OP units	0				$ 1	1,921		51	(1,973)
Effect of changes in ownership for consolidated entities	0					(12,621)		(396)	13,017
Equity-based compensation expense	867					70			797
Issuance of restricted common shares (in shares)					12,311
Issuance of restricted common shares	0
Vesting and forfeitures of restricted common shares, net (in shares)					(3,848)
Vesting and forfeitures of restricted common shares, net	(75)					(75)
Reduction in receivables from partners of the operating partnership	191								191
Preferred share dividends	(2,588)						(2,588)
Common share dividends	(14,099)						(14,099)
Distributions to noncontrolling interests	(14,515)								(14,515)
Other comprehensive loss	9,039							5,548	3,491
Net income	11,973						10,460		1,513
Balances (in shares) at Mar. 31, 2018				6,900,000
Balances (in shares) at Mar. 31, 2018					50,438,731
Balances at Mar. 31, 2018	1,284,688			$ 172,500	$ 504	700,762	(61,956)	17,485	455,393
Balances (in shares) at Dec. 31, 2017				6,900,000
Balances (in shares) at Dec. 31, 2017					50,284,934
Balances at Dec. 31, 2017	1,271,487			$ 172,500	$ 503	711,467	(55,729)	12,282	430,464
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Other comprehensive loss	13,423
Net income	25,014
Balances (in shares) at Jun. 30, 2018				6,900,000
Balances (in shares) at Jun. 30, 2018					50,539,575
Balances at Jun. 30, 2018	1,270,237			$ 172,500	$ 505	701,256	(73,307)	20,211	449,072
Balances (in shares) at Mar. 31, 2018				6,900,000
Balances (in shares) at Mar. 31, 2018					50,438,731
Balances at Mar. 31, 2018	1,284,688			$ 172,500	$ 504	700,762	(61,956)	17,485	455,393
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Redemptions of OP units (in shares)					101,248
Redemptions of OP units	0				$ 1	1,305		36	(1,342)
Effect of changes in ownership for consolidated entities	0					(877)		(10)	887
Equity-based compensation expense	919					66			853
Vesting and forfeitures of restricted common shares, net (in shares)					(404)
Vesting and forfeitures of restricted common shares, net	0					0
Reduction in receivables from partners of the operating partnership	156								156
Preferred share dividends	(2,587)						(2,587)
Common share dividends	(14,655)						(14,655)
Distributions to noncontrolling interests	(15,709)								(15,709)
Other comprehensive loss	4,384							2,700	1,684
Net income	13,041						5,891		7,150
Balances (in shares) at Jun. 30, 2018				6,900,000
Balances (in shares) at Jun. 30, 2018					50,539,575
Balances at Jun. 30, 2018	$ 1,270,237			$ 172,500	$ 505	701,256	(73,307)	20,211	449,072
Balances (in shares) at Dec. 31, 2018	6,900,000			6,900,000
Balances (in shares) at Dec. 31, 2018	56,654,009				56,654,009
Balances at Dec. 31, 2018	$ 1,402,299			$ 172,500	$ 567	844,276	(114,122)	13,618	485,460
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of equity units		32,856								32,856
Redemptions of OP units (in shares)					29,910
Redemptions of OP units	0				$ 0	250		7	(257)
Effect of changes in ownership for consolidated entities	0					(5,385)		(182)	5,567
Equity-based compensation expense	1,112					90			1,022
Issuance of LTIP units for acquisition expenses	5								5
Issuance of restricted common shares (in shares)					18,218
Issuance of restricted common shares	0
Vesting and forfeitures of restricted common shares, net (in shares)					(3,451)
Vesting and forfeitures of restricted common shares, net	(69)					(69)
Reduction in receivables from partners of the operating partnership	139								139
Preferred share dividends	(2,588)						(2,588)
Common share dividends	(17,010)						(17,010)
Distributions to noncontrolling interests	(17,181)								(17,181)
Other comprehensive loss	(9,315)							(5,917)	(3,398)
Net income	12,940						7,411		5,529
Balances (in shares) at Mar. 31, 2019				6,900,000
Balances (in shares) at Mar. 31, 2019					56,698,686
Balances at Mar. 31, 2019	$ 1,403,188			$ 172,500	$ 567	839,162	(126,309)	7,526	509,742
Balances (in shares) at Dec. 31, 2018	6,900,000			6,900,000
Balances (in shares) at Dec. 31, 2018	56,654,009				56,654,009
Balances at Dec. 31, 2018	$ 1,402,299			$ 172,500	$ 567	844,276	(114,122)	13,618	485,460
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Other comprehensive loss	(29,667)
Net income	$ 30,673
Balances (in shares) at Jun. 30, 2019	8,685,680			8,685,680
Balances (in shares) at Jun. 30, 2019	59,296,969				59,296,969
Balances at Jun. 30, 2019	$ 1,498,784			$ 217,142	$ 593	901,499	(156,192)	(5,466)	541,208
Balances (in shares) at Mar. 31, 2019				6,900,000
Balances (in shares) at Mar. 31, 2019					56,698,686
Balances at Mar. 31, 2019	1,403,188			$ 172,500	$ 567	839,162	(126,309)	7,526	509,742
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of equity units		$ 15,515	$ 8,540							$ 15,515	$ 8,540
Stock Issued During Period, Shares, New Issues													1,785,680			2,375,000
Stock Issued During Period, Value, New Issues												$ 43,624	$ 44,642	$ (1,018)	$ 70,637	$ 24	$ 70,613
Redemptions of OP units (in shares)					224,618
Redemptions of OP units	0				$ 2	1,839		28	(1,869)
Effect of changes in ownership for consolidated entities	0					(9,179)		(28)	9,207
Equity-based compensation expense	1,108					82			1,026
Issuance of LTIP units for acquisition expenses	56								56
Vesting and forfeitures of restricted common shares, net (in shares)					(1,335)
Vesting and forfeitures of restricted common shares, net	0					0
Preferred share dividends	(3,257)						(3,257)
Common share dividends	(18,970)						(18,970)
Distributions to noncontrolling interests	(19,038)								(19,038)
Other comprehensive loss	(20,352)							(12,992)	(7,360)
Net income	$ 17,733						(7,656)		25,389
Balances (in shares) at Jun. 30, 2019	8,685,680			8,685,680
Balances (in shares) at Jun. 30, 2019	59,296,969				59,296,969
Balances at Jun. 30, 2019	$ 1,498,784			$ 217,142	$ 593	$ 901,499	$ (156,192)	$ (5,466)	$ 541,208

CONDENSED CONSOLIDATED STATEM_4

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
OPERATING ACTIVITIES
Net income	$ 30,673	$ 25,014
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	50,178	43,757
Amortization of debt issuance costs	1,414	1,219
Amortization of debt discount and premium, net	(708)	(744)
Gain on sale of self storage properties	(2,814)	(391)
Equity-based compensation expense	2,220	1,786
Equity in losses (earnings) of unconsolidated real estate ventures	3,748	(48)
Distributions from unconsolidated real estate ventures	7,065	2,806
Change in assets and liabilities, net of effects of self storage property acquisitions:
Other assets	119	(916)
Accounts payable and accrued liabilities	2,893	1,863
Deferred revenue	(1,313)	(61)
Net Cash Provided by Operating Activities	93,475	74,285
INVESTING ACTIVITIES
Acquisition of self storage properties	(307,791)	(162,322)
Capital expenditures	(10,443)	(10,126)
Investments in and advances to unconsolidated real estate ventures	0	(2,390)
Distributions from unconsolidated real estate ventures	1,017	0
Deposits and advances for self storage property and other acquisitions	175	18,286
Expenditures for corporate furniture, equipment and other	(416)	(81)
Acquisition of interest in reinsurance company and related cash flows	6,600	0
Proceeds from sale of self storage properties	6,335	5,259
Net Cash Used In Investing Activities	(318,073)	(187,946)
FINANCING ACTIVITIES
Proceeds from issuance of common shares	70,637	0
Proceeds from issuance of preferred shares	43,624	0
Borrowings under debt financings	499,000	438,500
Receipts for OP unit subscriptions	318	606
Principal payments under debt financings	(306,538)	(252,417)
Payment of dividends to common shareholders	(35,980)	(28,754)
Distributions to preferred shareholders	(5,845)	(5,175)
Distributions to noncontrolling interests	(36,080)	(29,918)
Debt issuance costs	(987)	(1,829)
Equity offering costs	(161)	(231)
Net Cash Provided By Financing Activities	227,988	120,782
Increase in Cash, Cash Equivalents and Restricted Cash	3,390	7,121
CASH, CASH EQUIVALENTS AND RESTRICTED CASH
Beginning of period	16,363	16,407
End of period	19,753	23,528
Supplemental Cash Flow Information
Cash paid for interest	25,999	18,981
Operating lease right-of-use assets on balance sheet due to implementation of leases standard	22,971	0
Operating lease liabilities on balance sheet due to implementation of leases standard	$ 24,152	$ 0

ORGANIZATION AND NATURE OF OPER

ORGANIZATION AND NATURE OF OPERATIONS	6 Months Ended
	Jun. 30, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
ORGANIZATION AND NATURE OF OPERATIONS	ORGANIZATION AND NATURE OF OPERATIONS National Storage Affiliates Trust was organized in the state of Maryland on May 16, 2013 and is a fully integrated, self-administered and self-managed real estate investment trust focused on the self storage sector. As used herein, "NSA," the "Company," "we," "our," and "us" refers to National Storage Affiliates Trust and its consolidated subsidiaries, except where the context indicates otherwise. The Company has elected and believes that it has qualified to be taxed as a real estate investment trust for U.S. federal income tax purposes ("REIT") commencing with its taxable year ended December 31, 2015. Through its controlling interest as the sole general partner of NSA OP, LP (its "operating partnership"), a Delaware limited partnership formed on February 13, 2013, the Company is focused on the ownership, operation, and acquisition of self storage properties located within the top 100 metropolitan statistical areas throughout the United States. Pursuant to the Agreement of Limited Partnership (as amended, the "LP Agreement") of its operating partnership, the Company's operating partnership is authorized to issue preferred units, Class A Units ("OP units"), different series of Class B Units ("subordinated performance units"), and Long-Term Incentive Plan Units ("LTIP units"). The Company also owns certain of its self storage properties through other consolidated limited partnership subsidiaries of its operating partnership, which the Company refers to as "DownREIT partnerships." The DownREIT partnerships issue equity ownership interests that are intended to be economically equivalent to the Company's OP units ("DownREIT OP units") and subordinated performance units ("DownREIT subordinated performance units"). The Company owned 554 consolidated self storage properties in 29 states and Puerto Rico with approximately 33.8 million rentable square feet in approximately 269,000 storage units as of June 30, 2019 . These properties are managed with local operational focus and expertise by the Company and its participating regional operators ("PROs"). These PROs are SecurCare Self Storage, Inc. and its controlled affiliates ("SecurCare"), Kevin Howard Real Estate Inc., d/b/a Northwest Self Storage and its controlled affiliates ("Northwest"), Optivest Properties LLC and its controlled affiliates ("Optivest"), Guardian Storage Centers LLC and its controlled affiliates ("Guardian"), Move It Self Storage and its controlled affiliates ("Move It"), Arizona Mini Storage Management Company d/b/a Storage Solutions and its controlled affiliates ("Storage Solutions"), Hide-Away Storage Services, Inc. and its controlled affiliates ("Hide-Away"), an affiliate of Shader Brothers Corporation d/b/a Personal Mini Storage ("Personal Mini"), Southern Storage Management Systems, Inc. d/b/a Southern Self Storage ("Southern") and affiliates of Investment Real Estate Management, LLC d/b/a Moove In Self Storage of York, Pennsylvania ("Moove In"). As of June 30, 2019 , the Company also managed through its property management platform an additional portfolio of 175 properties owned by the Company's unconsolidated real estate ventures. These properties contain approximately 12.7 million rentable square feet, configured in approximately 104,000 storage units and located across 21 states. The Company owns a 25% equity interest in each of its unconsolidated real estate ventures. As of June 30, 2019 , in total, the Company operated and held ownership interests in 729 self storage properties located across 35 states and Puerto Rico with approximately 46.5 million rentable square feet in approximately 373,000 storage units.

SUMMARY OF SIGNIFICANT ACCOUNTI

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	6 Months Ended
	Jun. 30, 2019
Accounting Policies [Abstract]
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Basis of Presentation The accompanying condensed consolidated financial statements are presented on the accrual basis of accounting in accordance with U.S. generally accepted accounting principles ("GAAP") and have been prepared by the Company pursuant to the rules and regulations of the Securities and Exchange Commission (the "SEC") regarding interim financial reporting. Accordingly, certain information and footnote disclosures required by GAAP for complete financial statements have been condensed or omitted in accordance with such rules and regulations. In the opinion of management, all adjustments (consisting of normal recurring adjustments) considered necessary for a fair presentation of the condensed consolidated financial statements have been included. The Company's results of operations for the quarterly period ended June 30, 2019 are not necessarily indicative of the results to be expected for the full year or any other future period. Principles of Consolidation The Company's financial statements include the accounts of its operating partnership and its controlled subsidiaries. All significant intercompany balances and transactions have been eliminated in the consolidation of entities. When the Company obtains an economic interest in an entity, the Company evaluates the entity to determine if the entity is deemed a variable interest entity ("VIE"), and if the Company is deemed to be the primary beneficiary, in accordance with authoritative guidance issued on the consolidation of VIEs. When an entity is not deemed to be a VIE, the Company considers the provisions of additional guidance to determine whether the general partner controls a limited partnership or similar entity when the limited partners have certain rights. The Company consolidates all entities that are VIEs and of which the Company is deemed to be the primary beneficiary. The Company has determined that its operating partnership is a VIE. The sole significant asset of National Storage Affiliates Trust is its investment in its operating partnership, and consequently, substantially all of the Company’s assets and liabilities represent those assets and liabilities of its operating partnership. As of June 30, 2019 and December 31, 2018 , the Company's operating partnership was the primary beneficiary of, and therefore consolidated, 21 DownREIT partnerships that are considered VIEs, which owned 34 self storage properties. The net book value of the real estate owned by these VIEs was $236.8 million and $240.4 million as of June 30, 2019 and December 31, 2018 , respectively. For certain DownREIT partnerships which are subject to fixed rate mortgages payable, the carrying value of such fixed rate mortgages payable held by these VIEs was $137.4 million and $138.4 million as of June 30, 2019 and December 31, 2018 , respectively. The creditors of the consolidated VIEs do not have recourse to the Company's general credit. Revenue Recognition Rental revenue Rental revenue consists of space rentals and related fees. Management has determined that all of the Company's leases are operating leases. Substantially all leases may be terminated on a month-to-month basis and rental income is recognized ratably over the lease term using the straight-line method. Rents received in advance are deferred and recognized on a straight-line basis over the related lease term associated with the prepayment. Promotional discounts and other incentives are recognized as a reduction to rental income over the applicable lease term. Other property-related revenue Other property-related revenue primarily consists of ancillary revenues such as tenant insurance and/or tenant warranty protection-related access fees and sales of storage supplies which are recognized in the period earned. The Company and certain of the Company’s PROs have tenant insurance- and/or tenant warranty protection plan-related arrangements with insurance companies and the Company’s tenants. During the three months ended June 30, 2019 and 2018 , the Company recognized $2.2 million and $1.8 million , respectively, of tenant insurance and tenant warranty protection plan revenues and during the six months ended June 30, 2019 and 2018 , the Company recognized $4.3 million and $3.5 million , respectively, of tenant insurance and tenant warranty protection plan revenues. The Company sells boxes, packing supplies, locks and other retail merchandise at its properties. During the three months ended June 30, 2019 and 2018 , the Company recognized retail sales of $0.5 million and $0.4 million , respectively, and during the six months ended June 30, 2019 and 2018 , the Company recognized retail sales of $0.9 million and $0.8 million , respectively. Management fees and other revenue Management fees and other revenue consist of property management fees, platform fees, call center fees, acquisition fees, and a portion of tenant warranty protection or tenant insurance proceeds that the Company earns for managing and operating its unconsolidated real estate ventures. With respect to both the 2018 Joint Venture and the 2016 Joint Venture (as each are defined in Note 5), the Company provides supervisory and administrative property management services, centralized call center services, and technology platform and revenue management services to the properties in the unconsolidated real estate ventures. The property management fees are equal to 6% of monthly gross revenues and net sales revenues from the assets of the unconsolidated real estate ventures, and the platform fees are equal to $1,250 per month per unconsolidated real estate venture property. With respect to the 2016 Joint Venture only, the call center fees are equal to 1% of each of monthly gross revenues and net sales revenues from the 2016 Joint Venture properties. During the three months ended June 30, 2019 and 2018 , the Company recognized property management fees, call center fees and platform fees of $3.2 million and $1.4 million , respectively, and during the six months ended June 30, 2019 and 2018 , the Company recognized property management fees, call center fees and platform fees of $6.4 million and $2.7 million , respectively. For acquisition fees, the Company provides sourcing, underwriting and administration services to the unconsolidated real estate ventures. The 2016 Joint Venture paid the Company a $4.1 million acquisition fee equal to 0.65% of the gross capitalization (including debt and equity) of the original 66 -property 2016 Joint Venture portfolio (the "Initial 2016 JV Portfolio") in 2016, at the time of the Initial 2016 JV Portfolio acquisition. The 2018 Joint Venture paid the Company a $4.0 million acquisition fee related to the initial acquisition of properties by the 2018 Joint Venture (the "Initial 2018 JV Portfolio") in 2018, at the time of the Initial 2018 JV Portfolio acquisition. These fees are refundable to the unconsolidated real estate ventures, on a prorated basis, if the Company is removed as the managing member during the initial four year life of the unconsolidated real estate ventures and as such, the Company's performance obligation for these acquisition fees are satisfied over a four year period. As of June 30, 2019 and December 31, 2018 , the Company had deferred revenue related to the acquisition fees of $3.7 million and $4.6 million , respectively. The Company also earns acquisition fees for properties acquired by the unconsolidated real estate ventures subsequent to the Initial 2016 JV Portfolio and the Initial 2018 JV Portfolio. These fees are based on a percentage of the gross capitalization of the acquired assets determined by the members of the 2016 Joint Venture and the 2018 Joint Venture, and are generally earned when the unconsolidated real estate ventures obtain title and control of an acquired property. During the three months ended June 30, 2019 and 2018 , the Company recognized acquisition fees of $0.5 million and $0.3 million , respectively, and during the six months ended June 30, 2019 and 2018 , the Company recognized acquisition fees of $1.0 million and $0.6 million , respectively. An affiliate of the Company facilitates tenant warranty protection or tenant insurance programs for tenants of the properties in the unconsolidated real estate ventures in exchange for 50% of all proceeds from such programs at each unconsolidated real estate venture property. During the three months ended June 30, 2019 and 2018 , the Company recognized $1.2 million and $0.5 million , respectively, of revenue related to these activities and during the six months ended June 30, 2019 and 2018 , the Company recognized $2.4 million and $1.0 million , respectively, of revenue related to these activities. Gain on sale of self storage properties The Company recognizes gains from disposition of facilities only upon closing in accordance with the guidance on sales of nonfinancial assets. Profit on real estate sold is recognized upon closing when all, or substantially all, of the promised consideration has been received and is nonrefundable and the Company has transferred control of the facilities to the purchaser. Investments in Unconsolidated Real Estate Ventures The Company’s investments in its unconsolidated real estate ventures are recorded under the equity method of accounting in the accompanying condensed consolidated financial statements. Under the equity method, the Company’s investments in unconsolidated real estate ventures are stated at cost and adjusted for the Company’s share of net earnings or losses and reduced by distributions. Equity in earnings (losses) is recognized based on the Company’s ownership interest in the earnings (losses) of the unconsolidated real estate ventures. The Company follows the "nature of the distribution approach" for classification of distributions from its unconsolidated real estate ventures in its condensed consolidated statements of cash flows. Under this approach, distributions are reported on the basis of the nature of the activity or activities that generated the distributions as either a return on investment, which are classified as operating cash flows, or a return of investment (e.g., proceeds from the unconsolidated real estate ventures' sale of assets) which are reported as investing cash flows. Noncontrolling Interests All of the limited partner equity interests ("OP equity") in the operating partnership not held by the Company are reflected as noncontrolling interests. Noncontrolling interests also include ownership interests in DownREIT partnerships held by entities other than the operating partnership or its subsidiaries. In the condensed consolidated statements of operations, the Company allocates net income (loss) attributable to noncontrolling interests to arrive at net income (loss) attributable to National Storage Affiliates Trust. For transactions that result in changes to the Company's ownership interest in its operating partnership, the carrying amount of noncontrolling interests is adjusted to reflect such changes. The difference between the fair value of the consideration received or paid and the amount by which the noncontrolling interest is adjusted is reflected as an adjustment to additional paid-in capital on the condensed consolidated balance sheets. Allocation of Net Income (Loss) The distribution rights and priorities set forth in the operating partnership's LP Agreement differ from what is reflected by the underlying percentage ownership interests of the unitholders. Accordingly, the Company allocates GAAP income (loss) utilizing the hypothetical liquidation at book value ("HLBV") method, in which the Company allocates income or loss based on the change in each unitholders’ claim on the net assets of its operating partnership at period end after adjusting for any distributions or contributions made during such period. The HLBV method is commonly applied to equity investments where cash distribution percentages vary at different points in time and are not directly linked to an equity holder’s ownership percentage. The HLBV method is a balance sheet-focused approach to income (loss) allocation. A calculation is prepared at each balance sheet date to determine the amount that unitholders would receive if the operating partnership were to liquidate all of its assets (at GAAP net book value) and distribute the resulting proceeds to its creditors and unitholders based on the contractually defined liquidation priorities. The difference between the calculated liquidation distribution amounts at the beginning and the end of the reporting period, after adjusting for capital contributions and distributions, is used to derive each unitholder's share of the income (loss) for the period. Due to the stated liquidation priorities and because the HLBV method incorporates non-cash items such as depreciation expense, in any given period, income or loss may be allocated disproportionately to unitholders as compared to their respective ownership percentage in the operating partnership, and net income (loss) attributable to National Storage Affiliates Trust could be more or less net income than actual cash distributions received and more or less income or loss than what may be received in the event of an actual liquidation. Additionally, the HLBV method could result in net income (or net loss) attributable to National Storage Affiliates Trust during a period when the Company reports consolidated net loss (or net income), or net income (or net loss) attributable to National Storage Affiliates Trust in excess of the Company's consolidated net income (or net loss). The computations of basic and diluted earnings (loss) per share may be materially affected by these disproportionate income (loss) allocations, resulting in volatile fluctuations of basic and diluted earnings (loss) per share. Other Comprehensive Income (Loss) The Company has cash flow hedge derivative instruments that are measured at fair value with unrealized gains or losses recognized in other comprehensive income (loss) with a corresponding adjustment to accumulated other comprehensive income (loss) within equity, as discussed further in Note 12. Under the HLBV method of allocating income (loss) discussed above, a calculation is prepared at each balance sheet date by applying the HLBV method including, and excluding, the assets and liabilities resulting from the Company's cash flow hedge derivative instruments to determine comprehensive income (loss) attributable to National Storage Affiliates Trust. As a result of the distribution rights and priorities set forth in the operating partnership's LP Agreement, in any given period, other comprehensive income (loss) may be allocated disproportionately to unitholders as compared to their respective ownership percentage in the operating partnership and as compared to their respective allocation of net income (loss). Restricted Cash The Company's restricted cash consists of escrowed funds deposited with financial institutions for real estate taxes, insurance and other reserves for capital improvements in accordance with the Company's loan agreements. Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. Recent Accounting Pronouncements In February 2016, the Financial Accounting Standards Board ("FASB") issued ASU 2016-02, Leases, which amends the existing guidance for accounting for leases, including requiring lessors to account for leases using an approach that is substantially equivalent to existing guidance for sales-type leases, direct financing leases and operating leases and lessees to recognize most leases on-balance sheet as lease liabilities with corresponding right-of-use assets. In July 2018, the FASB issued ASU 2018-11, Leases - Targeted Improvements, which allows entities the option to apply the new standard at adoption date with a cumulative-effect adjustment in the period of adoption. The Company adopted ASU 2016-02 and ASU 2018-11 effective January 1, 2019 and applied it to leases that were in place on the effective date. The Company elected the practical expedients which permit the Company to combine lease and nonlease components and to not reassess (i) whether any expired or existing contracts are or contain leases, (ii) the lease classification for any expired or existing leases, and (iii) any initial direct costs for any existing leases as of the effective date. Results for reporting periods beginning January 1, 2019 are presented under ASU 2016-02 and ASU 2018-11. As a result, beginning on January 1, 2019, activity related to uncollectible accounts are recognized as a current-period adjustment within revenue. For periods prior to January 1, 2019, such amounts were previously included in operating expenses. The adoption of the lease standard did not result in a cumulative catch-up adjustment to opening equity. See Note 13 for additional detail about the Company's non-cancelable leasehold interest agreements where the Company is a lessee.

SHAREHOLDERS' EQUITY AND NONCON

SHAREHOLDERS' EQUITY AND NONCONTROLLING INTERESTS	6 Months Ended
	Jun. 30, 2019
Equity [Abstract]
SHAREHOLDERS' EQUITY AND NONCONTROLLING INTERESTS	SHAREHOLDERS' EQUITY AND NONCONTROLLING INTERESTS Shareholders' Equity At the Market ("ATM") Program On February 27, 2019, the Company entered into a sales agreement with certain sales agents, pursuant to which the Company may sell from time to time up to $250.0 million of the Company's common of beneficial interest, $0.01 par value per share ("common shares") and 6.000% Series A cumulative redeemable preferred shares of beneficial interest ("Series A preferred shares") in sales deemed to be "at the market" offerings. The sales agreement contemplates that, in addition to the issuance and sale by the Company of offered shares to or through the sale agents, the Company may enter into separate forward sale agreements with any forward purchaser. Forward sale agreements, if any, will include only the Company's common shares and will not include any Series A preferred shares. If the Company enters into a forward sale agreement with any forward purchaser, such forward purchaser will attempt to borrow from third parties and sell, through the related agent, acting as sales agent for such forward purchaser (each, a "forward seller"), offered shares, in an amount equal to the offered shares subject to such forward sale agreement, to hedge such forward purchaser’s exposure under such forward sale agreement. The Company may offer the common shares and Series A preferred shares through the agents, as the Company's sales agents, or, as applicable, as forward seller, or directly to the agents or forward sellers, acting as principals, by means of, among others, ordinary brokers’ transactions on the NYSE or otherwise at market prices prevailing at the time of sale or at negotiated prices. During the three and six months ended June 30, 2019 , the Company sold 2,375,000 of its common shares through the ATM program at an average offering price of $30.06 per share, resulting in net proceeds to the Company of approximately $70.6 million , after deducting compensation payable by the Company to such agents and offering expenses. In addition, during the three and six months ended June 30, 2019 , the Company sold 1,785,680 of its Series A preferred shares through the ATM program at an average offering price of $24.84 per share, resulting in net proceeds to the Company of approximately $43.6 million , after deducting compensation payable by the Company to such agents and offering expenses. Noncontrolling Interests All of the OP equity in the Company's operating partnership not held by the Company are reflected as noncontrolling interests. Noncontrolling interests also include ownership interests in DownREIT partnerships held by entities other than the Company's operating partnership. NSA is the general partner of its operating partnership and is authorized to cause its operating partnership to issue additional partner interests, including OP units and subordinated performance units, at such prices and on such other terms as it determines in its sole discretion. As of June 30, 2019 and December 31, 2018 , units reflecting noncontrolling interests consisted of the following: June 30, 2019 December 31, 2018 Series A-1 preferred units 684,421 343,719 OP units 30,491,509 28,874,103 Subordinated performance units 10,932,635 10,749,475 LTIP units 756,267 931,671 DownREIT units DownREIT OP units 1,848,261 1,834,786 DownREIT subordinated performance units 4,371,622 4,386,999 Total 49,084,715 47,120,753 Series A-1 Preferred Units The 6.000% Series A-1 Cumulative Redeemable Preferred Units ("Series A-1 preferred units") rank senior to OP units and subordinated performance units in the Company's operating partnership with respect to distributions and liquidation. The Series A-1 preferred units have a stated value of $25.00 per unit and receive distributions at an annual rate of 6.000% . These distributions are cumulative. The Series A-1 preferred units are redeemable at the option of the holder after the first anniversary of the date of issuance, which redemption obligations may be satisfied at the Company’s option in cash in an amount equal to the market value of an equivalent number of the Series A preferred shares or the issuance of Series A preferred shares on a one -for-one basis, subject to adjustments. The increase in Series A-1 preferred units outstanding from December 31, 2018 to June 30, 2019 was due to the issuance of Series A-1 preferred units in connection with the acquisition of self storage properties. OP Units and DownREIT OP units OP units in the Company's operating partnership are redeemable for cash or, at the Company's option, exchangeable for the Company's common shares on a one -for-one basis, and DownREIT OP units are redeemable for cash or, at the Company's option, exchangeable for OP units in its operating partnership on a one -for-one basis, subject to certain adjustments in each case. The holders of OP units are generally not entitled to elect redemption until one year after the issuance of the OP units. The holders of DownREIT OP units are generally not entitled to elect redemption until five years after the date of the contributor's initial contribution. The increase in OP Units outstanding from December 31, 2018 to June 30, 2019 was due to the issuance of 863,148 OP units related to the voluntary conversions of 913,680 subordinated performance units (as discussed further below), the issuance of 343,657 OP units in connection with the acquisition of self storage properties, 379,617 LTIP units which were converted into OP units and the issuance of 285,512 OP units in connection with the acquisition of an interest in a tenant reinsurance company and related cash flows, as discussed in Note 10, partially offset by the redemption of 254,528 OP units for common shares. The increase in DownREIT OP units outstanding from December 31, 2018 to June 30, 2019 was due to the issuance of 13,475 DownREIT OP units related to the conversion of 15,377 DownREIT subordinated performance units (as discussed further below). Subordinated Performance Units and DownREIT Subordinated Performance Units Subordinated performance units may also, under certain circumstances, be convertible into OP units which are exchangeable for common shares as described above, and DownREIT subordinated performance units may, under certain circumstances, be exchangeable for subordinated performance units on a one -for-one basis. Subordinated performance units are only convertible into OP units after a two year lock-out period and then generally (i) at the holder’s election only upon the achievement of certain performance thresholds relating to the properties to which such subordinated performance units relate or (ii) at the Company's election upon a retirement event of a PRO that holds such subordinated performance units or upon certain qualifying terminations. The holders of DownREIT subordinated performance units are generally not entitled to elect redemption until at least five years after the date of the contributor's initial contribution. Following such lock-out period, a holder of subordinated performance units in the Company's operating partnership may elect a voluntary conversion one time each year prior to December 1st to convert a pre-determined portion of such subordinated performance units into OP units in the Company's operating partnership, with such conversion effective January 1st of the following year, with each subordinated performance unit being converted into the number of OP units determined by dividing the average cash available for distribution, or CAD, per unit on the series of specific subordinated performance units over the one-year period prior to conversion by 110% of the CAD per unit on the OP units determined over the same period. CAD per unit on the series of specific subordinated performance units and OP units is determined by the Company based generally upon the application of the provisions of the LP Agreement applicable to the distributions of operating cash flow and capital transactions proceeds. The increase in subordinated performance units outstanding from December 31, 2018 to June 30, 2019 was due to the issuance of 1,096,840 subordinated performance units for co-investment by certain of the Company's PROs in connection with the acquisition of self storage properties partially offset by the voluntary conversion of 913,680 subordinated performance units into 863,148 OP units. The decrease in DownREIT subordinated performance units outstanding from December 31, 2018 to June 30, 2019 was due to the conversion of 15,377 DownREIT subordinated performance units into 13,475 DownREIT OP units. LTIP Units LTIP units are a special class of partnership interest in the Company's operating partnership that allow the holder to participate in the ordinary and liquidating distributions received by holders of the OP units (subject to the achievement of specified levels of profitability by the Company's operating partnership or the achievement of certain events). LTIP units may also, under certain circumstances, be convertible into OP units on a one -for-one basis, which are then exchangeable for common shares as described above. The decrease in LTIP units outstanding from December 31, 2018 to June 30, 2019 was due to the conversion of 379,617 LTIP units into OP units partially offset by the issuance of 204,213 compensatory LTIP units to employees, trustees and consultants, net of forfeitures.

SELF STORAGE PROPERTIES

SELF STORAGE PROPERTIES	6 Months Ended
	Jun. 30, 2019
Real Estate [Abstract]
SELF STORAGE PROPERTIES	SELF STORAGE PROPERTIES Self storage properties are summarized as follows (dollars in thousands): June 30, 2019 December 31, 2018 Land $ 640,052 $ 583,455 Buildings and improvements 2,369,152 2,048,281 Furniture and equipment 6,345 5,987 Total self storage properties 3,015,549 2,637,723 Less accumulated depreciation (289,886 ) (246,261 ) Self storage properties, net $ 2,725,663 $ 2,391,462 Depreciation expense related to self storage properties amounted to $22.7 million and $18.9 million during the three months ended June 30, 2019 and 2018 , respectively, and $44.2 million and $36.9 million during the six months ended June 30, 2019 and 2018 , respectively.

INVESTMENT IN UNCONSOLIDATED RE

INVESTMENT IN UNCONSOLIDATED REAL ESTATE VENTURES	6 Months Ended
	Jun. 30, 2019
Equity Method Investments and Joint Ventures [Abstract]
INVESTMENT IN UNCONSOLIDATED REAL ESTATE VENTURES	INVESTMENT IN UNCONSOLIDATED REAL ESTATE VENTURES 2018 Joint Venture As of June 30, 2019 , the Company's unconsolidated real estate venture, formed in September 2018 with an affiliate of Heitman America Real Estate REIT LLC (the "2018 Joint Venture"), owned and operated a portfolio of 103 self storage properties containing approximately 7.7 million rentable square feet, configured in over 63,000 storage units and located across 17 states. 2016 Joint Venture As of June 30, 2019 , the Company's unconsolidated real estate venture, formed in September 2016 with a state pension fund advised by Heitman Capital Management LLC (the "2016 Joint Venture"), owned and operated a portfolio of 72 properties containing approximately 4.9 million rentable square feet, configured in approximately 40,000 storage units and located across 13 states. During the six months ended June 30, 2019 , the 2016 Joint Venture sold to the Company one self storage property for a gross sales price of $4.1 million . See Note 10 for additional details about the Company's acquisition of the self storage property from the 2016 Joint Venture. The following table presents the combined condensed financial position of the Company's unconsolidated real estate ventures as of June 30, 2019 and December 31, 2018 (in thousands): June 30, 2019 December 31, 2018 ASSETS Self storage properties, net $ 1,863,002 $ 1,894,412 Other assets 29,489 50,915 Total assets $ 1,892,491 $ 1,945,327 LIABILITIES AND EQUITY Debt financing $ 947,493 $ 956,357 Other liabilities 19,973 16,516 Equity 925,025 972,454 Total liabilities and equity $ 1,892,491 $ 1,945,327 The following tables present the combined condensed operating information of the Company's unconsolidated real estate ventures for the three and six months ended June 30, 2019 and 2018 (in thousands): Three Months Ended June 30, 2019 2018 Total revenue $ 40,858 $ 15,196 Property operating expenses 12,544 5,000 Net operating income 28,314 10,196 Supervisory, administrative and other expenses (2,706 ) (1,072 ) Depreciation and amortization (21,888 ) (5,527 ) Interest expense (9,941 ) (2,928 ) Acquisition and other expenses (419 ) (275 ) Net (loss) income $ (6,640 ) $ 394 Six Months Ended June 30, 2019 2018 Total revenue $ 80,653 $ 30,002 Property operating expenses 25,088 10,293 Net operating income 55,565 19,709 Supervisory, administrative and other expenses (5,359 ) (2,129 ) Depreciation and amortization (43,714 ) (11,034 ) Interest expense (19,961 ) (5,827 ) Loss on sale of self storage properties (806 ) — Acquisition and other expenses (827 ) (537 ) Net (loss) income $ (15,102 ) $ 182 The combined condensed operating information in the tables above only includes information for the 2018 Joint Venture following the acquisition of the Initial 2018 JV Portfolio in September 2018.

SELF STORAGE PROPERTY ACQUISITI

SELF STORAGE PROPERTY ACQUISITIONS AND DISPOSITIONS	6 Months Ended
	Jun. 30, 2019
Business Combinations [Abstract]
SELF STORAGE PROPERTY ACQUISITIONS AND DISPOSITIONS	SELF STORAGE PROPERTY ACQUISITIONS AND DISPOSITIONS Acquisitions The Company acquired 56 self storage properties with an estimated fair value of $379.9 million during the six months ended June 30, 2019 . Of these acquisitions, 21 self storage properties with an estimated fair value of $145.5 million were acquired by the Company from its PROs and one self storage property with an estimated fair value of $4.1 million was acquired by the Company from the 2016 Joint Venture. The 56 self storage property acquisitions were accounted for as asset acquisitions and accordingly, $2.6 million of transaction costs related to the acquisitions were capitalized as part of the basis of the acquired properties. The Company recognized the estimated fair value of the acquired assets and assumed liabilities on the respective dates of such acquisitions. The Company allocated the total purchase price to the estimated fair value of tangible and intangible assets acquired, and liabilities assumed. The Company allocated a portion of the purchase price to identifiable intangible assets consisting of customer in-place leases which were recorded at estimated fair value of $9.2 million , resulting in a total fair value of $370.7 million allocated to real estate. The following table summarizes the investment in self storage property acquisitions completed by the Company during the six months ended June 30, 2019 (dollars in thousands): Acquisitions Closed During the Three Months Ended: Number of Properties Summary of Investment Cash and Acquisition Costs Value of OP Equity (1) Other Liabilities Total March 31, 2019 32 $ 160,531 $ 33,356 $ 674 $ 194,561 June 30, 2019 24 168,442 15,515 1,378 185,335 Total 56 $ 328,973 $ 48,871 $ 2,052 $ 379,896 (1) Value of OP equity represents the fair value of Series A-1 preferred units, OP units and subordinated performance units. Dispositions During the six months ended June 30, 2019 , the Company sold one self storage property to an unrelated third party. The gross sales price was $6.5 million and the Company recognized $2.8 million of gain on the sale.

OTHER ASSETS

OTHER ASSETS	6 Months Ended
	Jun. 30, 2019
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
OTHER ASSETS	OTHER ASSETS Other assets consist of the following (dollars in thousands): June 30, 2019 December 31, 2018 Customer in-place leases, net of accumulated amortization of $5,568 and $5,090, respectively $ 8,029 $ 4,063 Receivables: Trade, net 3,374 3,402 PROs and other affiliates 1,664 2,027 Receivables from unconsolidated real estate ventures 4,454 4,573 Property acquisition and other deposits 275 20,977 Interest rate swaps 2,186 16,164 Prepaid expenses and other 5,444 4,266 Corporate furniture, equipment and other, net 1,704 1,574 Trade name 3,200 3,200 Management contract, net of accumulated amortization of $1,918 and $1,564, respectively 8,703 9,057 Tenant reinsurance intangible, net of accumulated amortization of less than $100 14,580 — Goodwill 5,750 5,750 Total $ 59,363 $ 75,053 Amortization expense related to customer in-place leases amounted to $2.8 million and $3.3 million for the three months ended June 30, 2019 and 2018 , respectively, and $5.3 million and $6.3 million during the six months ended June 30, 2019 and 2018 , respectively. Amortization expense related to the management contract amounted to $0.2 million and $0.2 million for the three months ended June 30, 2019 and 2018 , respectively, and $0.4 million and $0.4 million during the six months ended June 30, 2019 and 2018 , respectively. Amortization expense related to the tenant reinsurance intangible amounted to less than $0.1 million for the three and six months ended June 30, 2019

DEBT FINANCING

DEBT FINANCING	6 Months Ended
	Jun. 30, 2019
Debt Disclosure [Abstract]
DEBT FINANCING	DEBT FINANCING The Company's outstanding debt as of June 30, 2019 and December 31, 2018 is summarized as follows (dollars in thousands): Interest Rate (1) June 30, 2019 December 31, 2018 Credit Facility: Revolving line of credit 3.80% $ 234,500 $ 139,500 Term loan A 2.91% 235,000 235,000 Term loan B 2.94% 155,000 155,000 Term loan C 3.71% 105,000 105,000 Term loan D 3.79% 125,000 125,000 2023 Term loan facility 2.83% 175,000 175,000 2028 Term loan facility 4.62% 75,000 75,000 2029 Term loan facility 4.27% 100,000 — Fixed rate mortgages payable 4.18% 265,601 268,138 Total principal 1,470,101 1,277,638 Unamortized debt issuance costs and debt premium, net (454 ) 464 Total debt $ 1,469,647 $ 1,278,102 (1) Represents the effective interest rate as of June 30, 2019 . Effective interest rate incorporates the stated rate plus the impact of interest rate cash flow hedges and discount and premium amortization, if applicable. For the revolving line of credit, the effective interest rate excludes fees for unused borrowings. As of June 30, 2019 , the Company's unsecured credit facility provided for total borrowings of $1.020 billion consisting of the following components: (i) a $400.0 million revolving line of credit (the "Revolver"), (ii) a tranche A term loan facility (the "Term Loan A"), which provides for a total borrowing commitment of up to $235.0 million , (iii) a tranche B term loan facility (the "Term Loan B"), which provides for a total borrowing commitment of up to $155.0 million , (iv) a tranche C term loan facility (the "Term Loan C"), which provides for a total borrowing commitment of up to $105.0 million and (v) a tranche D term loan facility, (the "Term Loan D" and together with the Revolver, the Term Loan A, Term Loan B and Term Loan C, the "credit facility"), which provides for a total borrowing commitment of up to $125.0 million . The Company has an expansion option under the credit facility, which, if exercised in full, would provide for a total borrowing capacity under the credit facility of $1.3 billion . As of June 30, 2019 , the Company had outstanding letters of credit totaling $5.7 million and would have had the capacity to borrow remaining Revolver commitments of $159.8 million while remaining in compliance with the credit facility's financial covenants. At June 30, 2019 , the Company was in compliance with all such covenants. As discussed in Note 14, on July 29, 2019 , the Company entered into a second amended and restated credit agreement with a syndicated group of lenders to increase the total borrowing capacity under the credit facility by $255.0 million for a total credit facility of $1.275 billion . 2029 Term Loan Facility On April 24, 2019, the Company entered into a credit agreement with BMO Harris Bank N.A. to make available an unsecured term loan facility that matures in April 2029 (the "2029 Term Loan Facility") in an aggregate amount of $100.0 million . The entire outstanding principal amount of, and all accrued but unpaid interest, is due on the maturity date. Interest rates applicable to loans under the 2029 Term Loan Facility are payable during such periods as such loans are LIBOR loans, at the applicable LIBOR based on a 1, 2, 3 or 6 month LIBOR period (as elected by the Company at the beginning of any applicable interest period) plus an applicable margin, and during the period that such loans are base rate loans, at the base rate under the 2029 Term Loan Facility in effect from time to time plus an applicable margin. The base rate under the 2029 Term Loan Facility is equal to the greatest of the BMO Harris Bank prime rate, the federal funds rate plus 0.50% or one month LIBOR plus 1.00% . The applicable margin for the 2029 Term Loan Facility is leverage-based and ranges from 1.85% to 2.30% for LIBOR loans and 0.85% to 1.30% for base rate loans; provided that after such time as the Company achieves an investment grade rating from at least two rating agencies, the Company may elect (but is not required to elect) that the 2029 Term Loan Facility be subject to rating-based margins ranging from 1.40% to 2.25% for LIBOR Loans and 0.40% to 1.25% for base rate loans. On April 24, 2019, the Company also entered into an interest rate swap agreement with a notional amount of $100.0 million that matures in April 2029 fixing the interest rate of the 2029 Term Loan Facility at an effective interest rate of 4.27% . The Company is required to comply with the same financial covenants under the 2029 Term Loan Facility as it is with the credit facility, 2023 Term Loan Facility and the 2028 Term Loan Facility. In addition, the terms of the 2029 Term Loan Facility contain customary affirmative and negative covenants that are consistent with those contained in the 2023 Term Loan Facility and 2028 Term Loan Facility, and, among other things, limit the Company's ability to make distributions, make certain investments, incur debt, incur liens and enter into certain transactions. 2029 And 2031 Senior Unsecured Notes As discussed in Note 14, on July 30, 2019 , the Company's operating partnership entered into an agreement to issue $100.0 million of 3.98% senior unsecured notes due August 30, 2029 and $50.0 million of 4.08% senior unsecured notes due August 30, 2031 in a private placement to certain institutional accredited investors. Future Debt Obligations Based on existing debt agreements in effect as of June 30, 2019 , the scheduled principal and maturity payments for the Company's outstanding borrowings are presented in the table below (in thousands): Year Ending December 31, Scheduled Principal and Maturity Payments Amortization of Premium and Unamortized Debt Issuance Costs Total Remainder of 2019 $ 2,590 $ (239 ) $ 2,351 2020 273,897 (816 ) 273,081 2021 242,603 (894 ) 241,709 2022 159,205 (556 ) 158,649 2023 377,049 (166 ) 376,883 2024 126,964 162 127,126 Thereafter 287,793 2,055 289,848 $ 1,470,101 $ (454 ) $ 1,469,647

EARNINGS PER SHARE

EARNINGS PER SHARE	6 Months Ended
	Jun. 30, 2019
Earnings Per Share [Abstract]
EARNINGS PER SHARE	EARNINGS PER SHARE The following table sets forth the computation of basic and diluted earnings (loss) per common share for the three and six months ended June 30, 2019 and 2018 , (in thousands, except per share amounts): Three Months Ended Six Months Ended 2019 2018 2019 2018 Earnings (loss) per common share - basic and diluted Numerator Net income $ 17,733 $ 13,041 $ 30,673 $ 25,014 Net income attributable to noncontrolling interests (25,389 ) (7,150 ) (30,918 ) (8,663 ) Net (loss) income attributable to National Storage Affiliates Trust (7,656 ) 5,891 (245 ) 16,351 Distributions to preferred shareholders (3,257 ) (2,587 ) (5,845 ) (5,175 ) Distributed and undistributed earnings allocated to participating securities (9 ) (7 ) (18 ) (14 ) Net (loss) income attributable to common shareholders - basic $ (10,922 ) $ 3,297 $ (6,108 ) $ 11,162 Effect of assumed conversion of dilutive securities — — — 8,356 Net (loss) income attributable to common shareholders - diluted $ (10,922 ) $ 3,297 $ (6,108 ) $ 19,518 Denominator Weighted average shares outstanding - basic 57,543 50,486 57,101 50,393 Effect of dilutive securities: Weighted average OP units outstanding — — — 29,060 Weighted average DownREIT OP unit equivalents outstanding — — — 1,835 Weighted average LTIP units outstanding — — — 323 Weighted average subordinated performance units and DownREIT subordinated performance unit equivalents — — — 18,881 Weighted average shares outstanding - diluted 57,543 50,486 57,101 100,492 Earnings (loss) per share - basic $ (0.19 ) $ 0.07 $ (0.11 ) $ 0.22 Earnings (loss) per share - diluted $ (0.19 ) $ 0.07 $ (0.11 ) $ 0.19 As discussed in Note 2 , the Company allocates GAAP income (loss) utilizing the HLBV method, in which the Company allocates income or loss based on the change in each unitholders' claim on the net assets of its operating partnership at period end after adjusting for any distributions or contributions made during such period. Due to the stated liquidation priorities and because the HLBV method incorporates non-cash items such as depreciation expense, in any given period, income or loss may be allocated disproportionately to National Storage Affiliates Trust and noncontrolling interests, resulting in volatile fluctuations of basic and diluted earnings (loss) per share. Outstanding equity interests of the Company's operating partnership and DownREIT partnerships are considered potential common shares for purposes of calculating diluted earnings (loss) per share as the unitholders may, through the exercise of redemption rights, obtain common shares, subject to various restrictions. Basic earnings per share is calculated based on the weighted average number of common shares outstanding during the period. Diluted earnings per share is calculated by further adjusting for the dilutive impact using the treasury stock method for unvested LTIP units subject to a service condition outstanding during the period and the if-converted method for any convertible securities outstanding during the period. Generally, following certain lock-out periods, OP units in the Company's operating partnership are redeemable for cash or, at the Company's option, exchangeable for common shares on a one -for-one basis, subject to certain adjustments and DownREIT OP units are redeemable for cash or, at the Company's option, exchangeable for OP units in its operating partnership on a one -for-one basis, subject to certain adjustments in each case. LTIP units may also, under certain circumstances, be convertible into OP units on a one-for-one basis, which are then exchangeable for common shares as described above. Certain LTIP units vested prior to or upon the completion of the Company's initial public offering and certain LTIP units have vested upon the satisfaction of a service condition or will vest upon the satisfaction of future service and market conditions. Vested LTIP units and unvested LTIP units that vest based on a service or market condition are allocated income or loss in a similar manner as OP units. Unvested LTIP units subject to a service or market condition are evaluated for dilution using the treasury stock method. For the three and six months ended June 30, 2019 , 448,089 unvested LTIP units that vest based on a service or market condition are excluded from the calculation of diluted earnings (loss) per share as they are not dilutive to earnings (loss) per share. In addition, certain LTIP units vest upon the future acquisition of properties sourced by PROs. For the three and six months ended June 30, 2019 , 224,000 unvested LTIP units that vest upon the future acquisition of properties are excluded from the calculation of diluted earnings (loss) per share because the contingency for the units to vest has not been attained as of the end of the reported periods. Subordinated performance units may also, under certain circumstances, be convertible into OP units which are exchangeable for common shares as described above, and DownREIT subordinated performance units may, under certain circumstances, be exchangeable for subordinated performance units on a one -for-one basis. Subordinated performance units are only convertible into OP units, after a two year lock-out period and then generally (i) at the holder’s election only upon the achievement of certain performance thresholds relating to the properties to which such subordinated performance units relate or (ii) at the Company's election upon a retirement event of a PRO that holds such subordinated performance units or upon certain qualifying terminations. Although subordinated performance units may only be convertible after a two year lock-out period, the Company assumes a hypothetical conversion of each subordinated performance unit (including each DownREIT subordinated performance unit) into OP units (with subsequently assumed redemption into common shares) for the purposes of calculating diluted weighted average common shares. This hypothetical conversion is calculated using historical financial information, and as a result, is not necessarily indicative of the results of operations, cash flows or financial position of the Company upon expiration of the two -year lock out period on conversions. For the three and six months ended June 30, 2019 , and the three months ended June 30, 2018, potential common shares totaling 54.0 million , 53.2 million and 50.6 million , respectively, related to OP units, DownREIT OP units, subordinated performance units and DownREIT subordinated performance units have been excluded from the calculation of diluted earnings (loss) per share as they are not dilutive to earnings (loss) per share. Participating securities, which consist of unvested restricted common shares, receive dividends equal to those received by common shares. The effect of participating securities for the periods presented above is calculated using the two-class method of allocating distributed and undistributed earnings.

RELATED PARTY TRANSACTIONS

RELATED PARTY TRANSACTIONS	6 Months Ended
	Jun. 30, 2019
Related Party Transactions [Abstract]
RELATED PARTY TRANSACTIONS	RELATED PARTY TRANSACTIONS Supervisory and Administrative Fees For the self storage properties that are managed by the PROs, the Company has entered into asset management agreements with the PROs to provide leasing, operating, supervisory and administrative services. The asset management agreements generally provide for fees ranging from 5% to 6% of gross revenue for the managed self storage properties. During the three months ended June 30, 2019 and 2018 , the Company incurred $4.9 million and $4.2 million , respectively, for supervisory and administrative fees to the PROs and during the six months ended June 30, 2019 and 2018 , the Company incurred $9.6 million and $8.2 million , respectively, for supervisory and administrative fees to the PROs. Such fees are included in general and administrative expenses in the accompanying condensed consolidated statements of operations. Payroll Services For the self storage properties that are managed by the PROs, the employees responsible for operations are employees of the PROs who charge the Company for the costs associated with the respective employees. For the three months ended June 30, 2019 and 2018 , the Company incurred $7.9 million and $7.2 million , respectively, for payroll and related costs reimbursable to these PROs and for the six months ended June 30, 2019 and 2018 , the Company incurred $15.7 million and $14.5 million , respectively, for payroll and related costs reimbursable to these PROs. Such costs are included in property operating expenses in the accompanying condensed consolidated statements of operations. Due Diligence Costs During the three months ended June 30, 2019 and 2018 , the Company incurred $0.3 million and $0.1 million , respectively, of expenses payable to certain PROs related to self storage property acquisitions sourced by the PROs and during the six months ended June 30, 2019 and 2018 , the Company incurred $0.6 million and $0.3 million , respectively, of expenses payable to certain PROs related to self storage property acquisitions sourced by the PROs. These expenses, which are based on the volume of transactions sourced by the PROs, are intended to reimburse the PROs for due diligence costs incurred in the sourcing and underwriting process. These due diligence costs are capitalized as part of the basis of the acquired self storage properties. Self Storage Property Acquisitions During the six months ended June 30, 2019 , the Company acquired one self storage property from the 2016 Joint Venture for $4.1 million . Acquisition of Interest in Reinsurance Company and Related Cash Flows On June 1, 2019, the Company, as acquiror, and Ground Up Development LLC ("Ground Up"), an affiliate of SecurCare and of the Company's chairman and chief executive officer, Arlen D. Nordhagen, entered into a Contribution and Purchase Agreement (the "Ground Up Contribution Agreement") whereby the Company acquired Ground Up’s ownership interest (approximately 5.5% ) in SBOA TI Reinsurance Ltd. (the "Reinsurance Company"), a Cayman Islands exempted company. The Reinsurance Company provides reinsurance for a self storage tenant insurance program issued by a licensed insurance company, whereby tenants of the Company's self storage facilities and tenants of other operators participating in the program can purchase insurance to cover damage or destruction to their personal property while stored at such facilities. The Company will now be entitled to receive its share of distributions of any profits generated by the Reinsurance Company, depending on actual losses incurred by the program. As part of the transaction, the Company also acquired the rights to the access fees previously earned by Ground Up associated with the tenant insurance-related arrangements. For NSA properties managed by SecurCare, in addition to the tenant insurance revenues the Company already receives directly from the program insurer, the Company will now be entitled to receive these additional access fees. The consideration paid for the interest in the Reinsurance Company was $15.1 million , which consisted of $6.6 million of cash and 285,512 OP units totaling $8.5 million . Of the total consideration transferred, Arlen D. Nordhagen received $2.2 million of cash and 95,170 OP Units totaling approximately $2.8 million . The Ground Up Contribution Agreement contains customary representations, warranties, covenants and agreements of the Company and Ground Up. The Company allocated the total purchase price to the estimated fair value of the assets acquired, consisting of $0.5 million of equity interest in the Reinsurance Company and $14.6 million as an intangible related to the acquired access fees and rights to control the tenant insurance-related arrangements. These assets are reported in other assets, net in the Company's condensed consolidated balance sheets. The intangible asset is amortized on a straight-line basis over 25 years, which approximates the weighted average remaining useful life of the SecurCare-managed properties, and is recorded in depreciation and amortization expense in the Company's condensed consolidated statements of operations.

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	6 Months Ended
	Jun. 30, 2019
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	COMMITMENTS AND CONTINGENCIES Legal Proceedings

FAIR VALUE MEASUREMENTS

FAIR VALUE MEASUREMENTS	6 Months Ended
	Jun. 30, 2019
Fair Value Disclosures [Abstract]
FAIR VALUE MEASUREMENTS	FAIR VALUE MEASUREMENTS Recurring Fair Value Measurements The Company sometimes limits its exposure to interest rate fluctuations by entering into interest rate swap agreements. The interest rate swap agreements moderate the Company's exposure to interest rate risk by effectively converting the interest on variable rate debt to a fixed rate. The Company measures its interest rate swap derivatives at fair value on a recurring basis. The changes in the fair value of derivatives designated and that qualify as cash flow hedges are recorded in accumulated other comprehensive income (loss) and are subsequently reclassified into earnings in the period that the hedged transaction affects earnings. Information regarding the Company's interest rate swaps measured at fair value, which are classified within Level 2 of the GAAP fair value hierarchy, is presented below (dollars in thousands): Fair value at December 31, 2017 $ 12,414 Gains on interest rate swaps reclassified into interest expense from accumulated other comprehensive income (232 ) Unrealized gains on interest rate swaps included in accumulated other comprehensive income 13,655 Fair value at June 30, 2018 $ 25,837 Fair value at December 31, 2018 $ 14,195 Gains on interest rate swaps reclassified into interest expense from accumulated other comprehensive income (2,553 ) Unrealized losses on interest rate swaps included in accumulated other comprehensive income (27,114 ) Fair value at June 30, 2019 $ (15,472 ) As of June 30, 2019 and December 31, 2018 , the Company had outstanding interest rate swaps with aggregate notional amounts of $970.0 million and $795.0 million , respectively, designated as cash flow hedges. As of June 30, 2019 , the Company's swaps had a weighted average remaining term of approximately 4.6 years . The fair value of these swaps are presented within accounts payable and accrued liabilities and other assets in the Company's balance sheets, and the Company recognizes any changes in the fair value as an adjustment of accumulated other comprehensive income (loss) within equity. If the forward rates at June 30, 2019 remain constant, the Company estimates that during the next 12 months , the Company would reclassify into earnings approximately $0.6 million of the unrealized losses included in accumulated other comprehensive income (loss). If market interest rates increase above the 1.92% weighted average fixed rate under these interest rate swaps, the Company will benefit from net cash payments due from its counterparties to the interest rate swaps. There were no transfers between levels of the three-tier fair value measurement hierarchy during the six months ended June 30, 2019 and 2018 . For financial assets and liabilities that utilize Level 2 inputs, the Company utilizes both direct and indirect observable price quotes, including LIBOR yield curves. The Company uses valuation techniques for Level 2 financial assets and liabilities which include LIBOR yield curves at the reporting date as well as assessing counterparty credit risk. Counterparties to these contracts are highly rated financial institutions. Although the Company has determined that the majority of the inputs used to value its derivatives fall within Level 2 of the fair value hierarchy, the credit valuation adjustments associated with the Company's derivatives utilize Level 3 inputs, such as estimates of current credit spreads, to evaluate the likelihood of default by the Company and the counterparties. As of June 30, 2019 , the Company determined that the effect of credit valuation adjustments on the overall valuation of its derivative positions are not significant to the overall valuation of its derivatives. Therefore, the Company has determined that its derivative valuations are appropriately classified in Level 2 of the fair value hierarchy. Fair Value Disclosures The carrying values of cash and cash equivalents, restricted cash, trade receivables, and accounts payable and accrued liabilities reflected in the balance sheets at June 30, 2019 and December 31, 2018 , approximate fair value due to the short term nature of these financial assets and liabilities. The carrying value of variable rate debt financing reflected in the balance sheets at June 30, 2019 and December 31, 2018 approximates fair value as the changes in their associated interest rates reflect the current market and credit risk is similar to when the loans were originally obtained. The combined principal balance of the Company's fixed rate mortgages payable was approximately $265.6 million as of June 30, 2019 with a fair value of approximately $283.0 million (categorized within Level 2 of the fair value hierarchy). In determining the fair value, the Company estimated a weighted average market interest rate of approximately 3.39% , compared to the weighted average contractual interest rate of 4.84% . The combined principal balance of the Company's fixed rate mortgages was approximately $268.1 million as of December 31, 2018 with a fair value of approximately $276.5 million . In determining the fair value as of December 31, 2018 , the Company estimated a weighted average market interest rate of approximately 4.17% , compared to the weighted average contractual interest rate of 4.85%

LEASES

LEASES	6 Months Ended
	Jun. 30, 2019
Leases [Abstract]
LEASES	LEASES The Company determines if a contractual arrangement is a lease at inception. As a lessee, the Company has non-cancelable lease agreements for real estate and its corporate office space that are classified as operating leases. The Company's operating leases are included in operating lease right-of-use ("ROU") assets and operating lease liabilities in its condensed consolidated balance sheets. Operating lease ROU assets and liabilities are recognized at commencement date based on the present value of lease payments over the lease term. As the Company's operating leases do not provide an implicit rate, the Company used its incremental borrowing rate based on the information available at commencement date in determining the discount rate for the present value of the lease payments. To the extent that the lease agreements provide for fixed increases throughout the term of the lease, the Company recognizes lease expense on a straight-line basis over the expected lease terms. Real Estate Leasehold Interests The Company has seven properties that are subject to non-cancelable leasehold interest agreements with remaining lease terms ranging from 15 to 73 years, inclusive of extension options that the Company anticipates exercising. Rent expense under these leasehold interest agreements is included in property operating expenses in the accompanying condensed consolidated statements of operations and amounted to $0.4 million and $0.4 million for the three months ended June 30, 2019 and 2018 , respectively, and $0.8 million and $0.8 million for the six months ended June 30, 2019 and 2018 , respectively. Office Leases The Company has entered into non-cancelable lease agreements for its corporate office space with remaining lease terms ranging from three to seven years. Rent expense related to these office leases is included in general and administrative expenses in the accompanying condensed consolidated statements of operations and amounted to $0.1 million and less than $0.1 million for the three months ended June 30, 2019 and 2018 , respectively, and $0.2 million and $0.1 million for the six months ended June 30, 2019 and 2018 , respectively. The weighted-average remaining lease term and the weighted-average discount rate for the Company's operating leases as of June 30, 2019 are as follows: June 30, 2019 Weighted-average remaining lease term Real estate leasehold interests 29 years Office leases 7 years Weighted-average remaining discount rate Real estate leasehold interests 4.9 % Office leases 4.1 % As of June 30, 2019 , the future minimum lease payments under the Company's operating leases, for which the Company is a lessee, are as follows (in thousands): Year Ending December 31, Real Estate Leasehold Interests Office Leases Total Remainder of 2019 $ 670 $ 116 $ 786 2020 1,385 286 1,671 2021 1,410 387 1,797 2022 1,425 381 1,806 2023 1,431 346 1,777 2024 through 2092 36,728 1,043 37,771 Total lease payments $ 43,049 $ 2,559 $ 45,608 Less imputed interest (21,091 ) (365 ) (21,456 ) Total $ 21,958 $ 2,194 $ 24,152 As of December 31, 2018, the future minimum lease payments under the Company's operating leases, for which the Company is a lessee, are as follows (in thousands): Year Ending December 31, Real Estate Leasehold Interests Office Leases Total Remainder of 2019 $ 1,334 $ 345 $ 1,679 2020 1,379 398 1,777 2021 1,404 387 1,791 2022 1,419 381 1,800 2023 1,424 346 1,770 2024 through 2092 36,074 1,073 37,147 Total lease payments $ 43,034 $ 2,930 $ 45,964

SUBSEQUENT EVENTS

SUBSEQUENT EVENTS	6 Months Ended
	Jun. 30, 2019
Subsequent Events [Abstract]
SUBSEQUENT EVENTS	SUBSEQUENT EVENTS 2029 And 2031 Senior Unsecured Notes On July 30, 2019 , the operating partnership as issuer, and the Company, entered into a Note Purchase Agreement (the "Note Purchase Agreement") which provides for the private placement of $100.0 million of 3.98% senior unsecured notes due August 30, 2029 (the " 2029 Notes") and $50.0 million of 4.08% senior unsecured notes due August 30, 2031 (the " 2031 Notes" and together with the 2029 Notes the "Senior Unsecured Notes") to certain institutional accredited investors. The Senior Unsecured Notes are governed by the Note Purchase Agreement and the sale and purchase of the Senior Unsecured Notes is expected to occur on August 30, 2019, subject to customary closing conditions. Interest is payable semiannually, on August 30th and February 28th of each year, commencing on February 28, 2020. The Senior Unsecured Notes are senior unsecured obligations of the Company and will be jointly and severally guaranteed by certain of the Company's subsidiaries, as subsidiary guarantors, upon issuance. The Senior Unsecured Notes rank pari passu with the amended credit facility, the 2023 Term Loan Facility, 2028 Term Loan Facility, and the 2029 Term Loan Facility. The Note Purchase Agreement contains financial covenants that are substantially similar to those described under the heading "Credit Facility Amendment" below. In addition, the terms of the Note Purchase Agreement contain customary affirmative and negative covenants that, among other things, limit the Company's ability to make distributions or certain investments, incur debt, incur liens and enter into certain transactions. Credit Facility Amendment On July 29, 2019 , the operating partnership, as borrower, the Company, and certain of the operating partnership's subsidiaries, as subsidiary guarantors, entered into a second amended and restated credit agreement with a syndicated group of lenders, which extended the maturities, enhanced the terms in line with the current market and increased the total borrowing capacity under the credit facility by $255.0 million for a total credit facility of $1.275 billion (the "amended credit facility"). The amended credit facility consists of the following components: (i) a Revolver which provides for a total borrowing commitment up to $500.0 million , whereby the Company may borrow, repay and re-borrow amounts under the Revolver, (ii) a $125.0 million Term Loan A, (iii) a $250.0 million Term Loan B, (iv) a $225.0 million Term Loan C, and (v) a $175.0 million Term Loan D. The Company has an expansion option under the amended credit facility, which if exercised in full, would provide for a total borrowing capacity under the amended credit facility of $1.750 billion . The Revolver matures in January 2024; provided that the Company may elect to extend the maturity to June 2024 by paying an extension fee of 0.075% of the total borrowing commitment thereunder at the time of extension and meeting other customary conditions with respect to compliance. The Term Loan A matures in January 2023, the Term Loan B matures in July 2024, the Term Loan C matures in January 2025 and the Term Loan D matures in July 2026. The amended credit facility is not subject to any scheduled reduction or amortization payments prior to maturity. Interest rates applicable to loans under the amended credit facility are determined based on a 1, 2, 3 or 6 month LIBOR period (as elected by the Company at the beginning of any applicable interest period) plus an applicable margin or a base rate, determined by the greatest of the Key Bank prime rate, the federal funds rate plus 0.50% or one month LIBOR plus 1.00% , plus an applicable margin. The applicable margins for the amended credit facility are leverage based and range from 1.15% to 2.20% for LIBOR loans and 0.15% to 1.20% for base rate loans; provided that after such time as the Company achieves an investment grade rating as defined in the amended credit facility, the Company may elect (but is not required to elect) (a "credit rating pricing election") that the amended credit facility be subject to applicable margins ranging from 0.78% to 2.25% for LIBOR loans and 0.00% to 1.25% for base rate loans. The Company is also required to pay usage based fees ranging from 0.15% to 0.20% with respect to the unused portion of the Revolver; provided that if the Company makes a credit rating pricing election as defined in the amended credit facility, the Company will be required to pay rating based fees ranging from 0.125% to 0.300% with respect to the entire Revolver in lieu of any usage based fees. On July 29, 2019 , the Company entered into interest rate swap agreements which together with the Company's existing interest rate swap agreements, fix the interest rates through maturity for the Term Loan A, Term Loan B, Term Loan C and Term Loan D. As of August 1, 2019, the Term Loan A, Term Loan B, Term Loan C and Term Loan D had effective interest rates of 3.74% , 2.91% , 2.80% and 3.57% , respectively. As of July 29, 2019 , the Company had outstanding letters of credit totaling $5.7 million and would have had the capacity to borrow remaining Revolver commitments of $395.5 million while remaining in compliance with the amended credit facility's financial covenants described in the following paragraph. The Company is required to comply with the following financial covenants under the amended credit facility: • Maximum total leverage ratio not to exceed 60% , provided, however, the Company is permitted to maintain a ratio of up to 65% up to two (2) consecutive fiscal quarters immediately following the quarter in which a material acquisition (as defined in the amended credit facility) occurs • Minimum fixed charge coverage ratio of at least 1.5 x • Maximum unsecured debt to unencumbered asset value ratio not to exceed 60% , provided, however, the Company shall be permitted to maintain a ratio of up to 65% up to two (2) consecutive fiscal quarters immediately following the quarter in which a material acquisition (as defined in the amended credit facility) occurs • Unencumbered adjusted net operating income to unsecured interest expense of at least 2.0 x On July 29, 2019, the financial covenants and certain other terms of each of the 2023 Term Loan Facility, 2028 Term Loan Facility, and the 2029 Term Loan Facility were amended to make such terms substantially similar to those in the amended credit facility. In addition, the terms of the amended credit facility contain customary affirmative and negative covenants that, among other things, limit the Company's ability to make distributions or certain investments, incur debt, incur liens and enter into certain transactions.

SUMMARY OF SIGNIFICANT ACCOUN_2

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	6 Months Ended
	Jun. 30, 2019
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation The accompanying condensed consolidated financial statements are presented on the accrual basis of accounting in accordance with U.S. generally accepted accounting principles ("GAAP") and have been prepared by the Company pursuant to the rules and regulations of the Securities and Exchange Commission (the "SEC") regarding interim financial reporting. Accordingly, certain information and footnote disclosures required by GAAP for complete financial statements have been condensed or omitted in accordance with such rules and regulations. In the opinion of management, all adjustments (consisting of normal recurring adjustments) considered necessary for a fair presentation of the condensed consolidated financial statements have been included. The Company's results of operations for the quarterly period ended June 30, 2019 are not necessarily indicative of the results to be expected for the full year or any other future period.
Principles of Consolidation	Principles of Consolidation
Variable Interest Entities	When the Company obtains an economic interest in an entity, the Company evaluates the entity to determine if the entity is deemed a variable interest entity ("VIE"), and if the Company is deemed to be the primary beneficiary, in accordance with authoritative guidance issued on the consolidation of VIEs. When an entity is not deemed to be a VIE, the Company considers the provisions of additional guidance to determine whether the general partner controls a limited partnership or similar entity when the limited partners have certain rights. The Company consolidates all entities that are VIEs and of which the Company is deemed to be the primary beneficiary. The Company has determined that its operating partnership is a VIE. The sole significant asset of National Storage Affiliates Trust is its investment in its operating partnership, and consequently, substantially all of the Company’s assets and liabilities represent those assets and liabilities of its operating partnership.
Revenue Recognition - Rental revenue	Rental revenue
Revenue Recognition - Other property-related revenue, management fees and other revenue	Other property-related revenue Other property-related revenue primarily consists of ancillary revenues such as tenant insurance and/or tenant warranty protection-related access fees and sales of storage supplies which are recognized in the period earned. The Company and certain of the Company’s PROs have tenant insurance- and/or tenant warranty protection plan-related arrangements with insurance companies and the Company’s tenants. During the three months ended June 30, 2019 and 2018 , the Company recognized $2.2 million and $1.8 million , respectively, of tenant insurance and tenant warranty protection plan revenues and during the six months ended June 30, 2019 and 2018 , the Company recognized $4.3 million and $3.5 million , respectively, of tenant insurance and tenant warranty protection plan revenues. The Company sells boxes, packing supplies, locks and other retail merchandise at its properties. During the three months ended June 30, 2019 and 2018 , the Company recognized retail sales of $0.5 million and $0.4 million , respectively, and during the six months ended June 30, 2019 and 2018 , the Company recognized retail sales of $0.9 million and $0.8 million , respectively. Management fees and other revenue Management fees and other revenue consist of property management fees, platform fees, call center fees, acquisition fees, and a portion of tenant warranty protection or tenant insurance proceeds that the Company earns for managing and operating its unconsolidated real estate ventures. With respect to both the 2018 Joint Venture and the 2016 Joint Venture (as each are defined in Note 5), the Company provides supervisory and administrative property management services, centralized call center services, and technology platform and revenue management services to the properties in the unconsolidated real estate ventures. The property management fees are equal to 6% of monthly gross revenues and net sales revenues from the assets of the unconsolidated real estate ventures, and the platform fees are equal to $1,250 per month per unconsolidated real estate venture property. With respect to the 2016 Joint Venture only, the call center fees are equal to 1% of each of monthly gross revenues and net sales revenues from the 2016 Joint Venture properties. During the three months ended June 30, 2019 and 2018 , the Company recognized property management fees, call center fees and platform fees of $3.2 million and $1.4 million , respectively, and during the six months ended June 30, 2019 and 2018 , the Company recognized property management fees, call center fees and platform fees of $6.4 million and $2.7 million , respectively. For acquisition fees, the Company provides sourcing, underwriting and administration services to the unconsolidated real estate ventures. The 2016 Joint Venture paid the Company a $4.1 million acquisition fee equal to 0.65% of the gross capitalization (including debt and equity) of the original 66 -property 2016 Joint Venture portfolio (the "Initial 2016 JV Portfolio") in 2016, at the time of the Initial 2016 JV Portfolio acquisition. The 2018 Joint Venture paid the Company a $4.0 million acquisition fee related to the initial acquisition of properties by the 2018 Joint Venture (the "Initial 2018 JV Portfolio") in 2018, at the time of the Initial 2018 JV Portfolio acquisition. These fees are refundable to the unconsolidated real estate ventures, on a prorated basis, if the Company is removed as the managing member during the initial four year life of the unconsolidated real estate ventures and as such, the Company's performance obligation for these acquisition fees are satisfied over a four year period. As of June 30, 2019 and December 31, 2018 , the Company had deferred revenue related to the acquisition fees of $3.7 million and $4.6 million , respectively. The Company also earns acquisition fees for properties acquired by the unconsolidated real estate ventures subsequent to the Initial 2016 JV Portfolio and the Initial 2018 JV Portfolio. These fees are based on a percentage of the gross capitalization of the acquired assets determined by the members of the 2016 Joint Venture and the 2018 Joint Venture, and are generally earned when the unconsolidated real estate ventures obtain title and control of an acquired property. During the three months ended June 30, 2019 and 2018 , the Company recognized acquisition fees of $0.5 million and $0.3 million , respectively, and during the six months ended June 30, 2019 and 2018 , the Company recognized acquisition fees of $1.0 million and $0.6 million , respectively. An affiliate of the Company facilitates tenant warranty protection or tenant insurance programs for tenants of the properties in the unconsolidated real estate ventures in exchange for 50% of all proceeds from such programs at each unconsolidated real estate venture property. During the three months ended June 30, 2019 and 2018 , the Company recognized $1.2 million and $0.5 million , respectively, of revenue related to these activities and during the six months ended June 30, 2019 and 2018 , the Company recognized $2.4 million and $1.0 million , respectively, of revenue related to these activities.
Gain on sale of self storage properties	Gain on sale of self storage properties
Investments in Unconsolidated Real Estate Ventures	Investments in Unconsolidated Real Estate Ventures The Company’s investments in its unconsolidated real estate ventures are recorded under the equity method of accounting in the accompanying condensed consolidated financial statements. Under the equity method, the Company’s investments in unconsolidated real estate ventures are stated at cost and adjusted for the Company’s share of net earnings or losses and reduced by distributions. Equity in earnings (losses) is recognized based on the Company’s ownership interest in the earnings (losses) of the unconsolidated real estate ventures. The Company follows the "nature of the distribution approach" for classification of distributions from its unconsolidated real estate ventures in its condensed consolidated statements of cash flows. Under this approach, distributions are reported on the basis of the nature of the activity or activities that generated the distributions as either a return on investment, which are classified as operating cash flows, or a return of investment (e.g., proceeds from the unconsolidated real estate ventures' sale of assets) which are reported as investing cash flows.
Noncontrolling Interests	Noncontrolling Interests All of the limited partner equity interests ("OP equity") in the operating partnership not held by the Company are reflected as noncontrolling interests. Noncontrolling interests also include ownership interests in DownREIT partnerships held by entities other than the operating partnership or its subsidiaries. In the condensed consolidated statements of operations, the Company allocates net income (loss) attributable to noncontrolling interests to arrive at net income (loss) attributable to National Storage Affiliates Trust. For transactions that result in changes to the Company's ownership interest in its operating partnership, the carrying amount of noncontrolling interests is adjusted to reflect such changes. The difference between the fair value of the consideration received or paid and the amount by which the noncontrolling interest is adjusted is reflected as an adjustment to additional paid-in capital on the condensed consolidated balance sheets.
Allocation of Net Income (Loss)	Allocation of Net Income (Loss) The distribution rights and priorities set forth in the operating partnership's LP Agreement differ from what is reflected by the underlying percentage ownership interests of the unitholders. Accordingly, the Company allocates GAAP income (loss) utilizing the hypothetical liquidation at book value ("HLBV") method, in which the Company allocates income or loss based on the change in each unitholders’ claim on the net assets of its operating partnership at period end after adjusting for any distributions or contributions made during such period. The HLBV method is commonly applied to equity investments where cash distribution percentages vary at different points in time and are not directly linked to an equity holder’s ownership percentage. The HLBV method is a balance sheet-focused approach to income (loss) allocation. A calculation is prepared at each balance sheet date to determine the amount that unitholders would receive if the operating partnership were to liquidate all of its assets (at GAAP net book value) and distribute the resulting proceeds to its creditors and unitholders based on the contractually defined liquidation priorities. The difference between the calculated liquidation distribution amounts at the beginning and the end of the reporting period, after adjusting for capital contributions and distributions, is used to derive each unitholder's share of the income (loss) for the period. Due to the stated liquidation priorities and because the HLBV method incorporates non-cash items such as depreciation expense, in any given period, income or loss may be allocated disproportionately to unitholders as compared to their respective ownership percentage in the operating partnership, and net income (loss) attributable to National Storage Affiliates Trust could be more or less net income than actual cash distributions received and more or less income or loss than what may be received in the event of an actual liquidation. Additionally, the HLBV method could result in net income (or net loss) attributable to National Storage Affiliates Trust during a period when the Company reports consolidated net loss (or net income), or net income (or net loss) attributable to National Storage Affiliates Trust in excess of the Company's consolidated net income (or net loss). The computations of basic and diluted earnings (loss) per share may be materially affected by these disproportionate income (loss) allocations, resulting in volatile fluctuations of basic and diluted earnings (loss) per share.
Other Comprehensive Income (Loss)	Other Comprehensive Income (Loss)
Restricted Cash	Restricted Cash
Use of Estimates	Use of Estimates
Recent Accounting Pronouncements	Recent Accounting Pronouncements In February 2016, the Financial Accounting Standards Board ("FASB") issued ASU 2016-02, Leases, which amends the existing guidance for accounting for leases, including requiring lessors to account for leases using an approach that is substantially equivalent to existing guidance for sales-type leases, direct financing leases and operating leases and lessees to recognize most leases on-balance sheet as lease liabilities with corresponding right-of-use assets. In July 2018, the FASB issued ASU 2018-11, Leases - Targeted Improvements, which allows entities the option to apply the new standard at adoption date with a cumulative-effect adjustment in the period of adoption. The Company adopted ASU 2016-02 and ASU 2018-11 effective January 1, 2019 and applied it to leases that were in place on the effective date. The Company elected the practical expedients which permit the Company to combine lease and nonlease components and to not reassess (i) whether any expired or existing contracts are or contain leases, (ii) the lease classification for any expired or existing leases, and (iii) any initial direct costs for any existing leases as of the effective date. Results for reporting periods beginning January 1, 2019 are presented under ASU 2016-02 and ASU 2018-11. As a result, beginning on January 1, 2019, activity related to uncollectible accounts are recognized as a current-period adjustment within revenue. For periods prior to January 1, 2019, such amounts were previously included in operating expenses. The adoption of the lease standard did not result in a cumulative catch-up adjustment to opening equity. See Note 13 for additional detail about the Company's non-cancelable leasehold interest agreements where the Company is a lessee.

SHAREHOLDERS' EQUITY AND NONC_2

SHAREHOLDERS' EQUITY AND NONCONTROLLING INTERESTS (Tables)	6 Months Ended
	Jun. 30, 2019
Equity [Abstract]
Schedule of outstanding equity interests	As of June 30, 2019 and December 31, 2018 , units reflecting noncontrolling interests consisted of the following: June 30, 2019 December 31, 2018 Series A-1 preferred units 684,421 343,719 OP units 30,491,509 28,874,103 Subordinated performance units 10,932,635 10,749,475 LTIP units 756,267 931,671 DownREIT units DownREIT OP units 1,848,261 1,834,786 DownREIT subordinated performance units 4,371,622 4,386,999 Total 49,084,715 47,120,753

SELF STORAGE PROPERTIES (Tables

SELF STORAGE PROPERTIES (Tables)	6 Months Ended
	Jun. 30, 2019
Real Estate [Abstract]
Schedule of self storage properties	Self storage properties are summarized as follows (dollars in thousands): June 30, 2019 December 31, 2018 Land $ 640,052 $ 583,455 Buildings and improvements 2,369,152 2,048,281 Furniture and equipment 6,345 5,987 Total self storage properties 3,015,549 2,637,723 Less accumulated depreciation (289,886 ) (246,261 ) Self storage properties, net $ 2,725,663 $ 2,391,462

INVESTMENT IN UNCONSOLIDATED _2

INVESTMENT IN UNCONSOLIDATED REAL ESTATE VENTURES (Tables)	6 Months Ended
	Jun. 30, 2019
Equity Method Investments and Joint Ventures [Abstract]
Schedule of condensed financial information of joint ventures	The following table presents the combined condensed financial position of the Company's unconsolidated real estate ventures as of June 30, 2019 and December 31, 2018 (in thousands): June 30, 2019 December 31, 2018 ASSETS Self storage properties, net $ 1,863,002 $ 1,894,412 Other assets 29,489 50,915 Total assets $ 1,892,491 $ 1,945,327 LIABILITIES AND EQUITY Debt financing $ 947,493 $ 956,357 Other liabilities 19,973 16,516 Equity 925,025 972,454 Total liabilities and equity $ 1,892,491 $ 1,945,327 The following tables present the combined condensed operating information of the Company's unconsolidated real estate ventures for the three and six months ended June 30, 2019 and 2018 (in thousands): Three Months Ended June 30, 2019 2018 Total revenue $ 40,858 $ 15,196 Property operating expenses 12,544 5,000 Net operating income 28,314 10,196 Supervisory, administrative and other expenses (2,706 ) (1,072 ) Depreciation and amortization (21,888 ) (5,527 ) Interest expense (9,941 ) (2,928 ) Acquisition and other expenses (419 ) (275 ) Net (loss) income $ (6,640 ) $ 394 Six Months Ended June 30, 2019 2018 Total revenue $ 80,653 $ 30,002 Property operating expenses 25,088 10,293 Net operating income 55,565 19,709 Supervisory, administrative and other expenses (5,359 ) (2,129 ) Depreciation and amortization (43,714 ) (11,034 ) Interest expense (19,961 ) (5,827 ) Loss on sale of self storage properties (806 ) — Acquisition and other expenses (827 ) (537 ) Net (loss) income $ (15,102 ) $ 182 The combined condensed operating information in the tables above only includes information for the 2018 Joint Venture following the acquisition of the Initial 2018 JV Portfolio in September 2018.

SELF STORAGE PROPERTY ACQUISI_2

SELF STORAGE PROPERTY ACQUISITIONS AND DISPOSITIONS (Tables)	6 Months Ended
	Jun. 30, 2019
Business Combinations [Abstract]
Schedule of investments in self storage property acquisitions	The following table summarizes the investment in self storage property acquisitions completed by the Company during the six months ended June 30, 2019 (dollars in thousands): Acquisitions Closed During the Three Months Ended: Number of Properties Summary of Investment Cash and Acquisition Costs Value of OP Equity (1) Other Liabilities Total March 31, 2019 32 $ 160,531 $ 33,356 $ 674 $ 194,561 June 30, 2019 24 168,442 15,515 1,378 185,335 Total 56 $ 328,973 $ 48,871 $ 2,052 $ 379,896 (1)

OTHER ASSETS (Tables)

OTHER ASSETS (Tables)	6 Months Ended
	Jun. 30, 2019
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Schedule of other assets	Other assets consist of the following (dollars in thousands): June 30, 2019 December 31, 2018 Customer in-place leases, net of accumulated amortization of $5,568 and $5,090, respectively $ 8,029 $ 4,063 Receivables: Trade, net 3,374 3,402 PROs and other affiliates 1,664 2,027 Receivables from unconsolidated real estate ventures 4,454 4,573 Property acquisition and other deposits 275 20,977 Interest rate swaps 2,186 16,164 Prepaid expenses and other 5,444 4,266 Corporate furniture, equipment and other, net 1,704 1,574 Trade name 3,200 3,200 Management contract, net of accumulated amortization of $1,918 and $1,564, respectively 8,703 9,057 Tenant reinsurance intangible, net of accumulated amortization of less than $100 14,580 — Goodwill 5,750 5,750 Total $ 59,363 $ 75,053

DEBT FINANCING (Tables)

DEBT FINANCING (Tables)	6 Months Ended
	Jun. 30, 2019
Debt Disclosure [Abstract]
Schedule of debt	The Company's outstanding debt as of June 30, 2019 and December 31, 2018 is summarized as follows (dollars in thousands): Interest Rate (1) June 30, 2019 December 31, 2018 Credit Facility: Revolving line of credit 3.80% $ 234,500 $ 139,500 Term loan A 2.91% 235,000 235,000 Term loan B 2.94% 155,000 155,000 Term loan C 3.71% 105,000 105,000 Term loan D 3.79% 125,000 125,000 2023 Term loan facility 2.83% 175,000 175,000 2028 Term loan facility 4.62% 75,000 75,000 2029 Term loan facility 4.27% 100,000 — Fixed rate mortgages payable 4.18% 265,601 268,138 Total principal 1,470,101 1,277,638 Unamortized debt issuance costs and debt premium, net (454 ) 464 Total debt $ 1,469,647 $ 1,278,102 (1) Represents the effective interest rate as of June 30, 2019 . Effective interest rate incorporates the stated rate plus the impact of interest rate cash flow hedges and discount and premium amortization, if applicable. For the revolving line of credit, the effective interest rate excludes fees for unused borrowings.
Schedule of future debt maturities	Based on existing debt agreements in effect as of June 30, 2019 , the scheduled principal and maturity payments for the Company's outstanding borrowings are presented in the table below (in thousands): Year Ending December 31, Scheduled Principal and Maturity Payments Amortization of Premium and Unamortized Debt Issuance Costs Total Remainder of 2019 $ 2,590 $ (239 ) $ 2,351 2020 273,897 (816 ) 273,081 2021 242,603 (894 ) 241,709 2022 159,205 (556 ) 158,649 2023 377,049 (166 ) 376,883 2024 126,964 162 127,126 Thereafter 287,793 2,055 289,848 $ 1,470,101 $ (454 ) $ 1,469,647

EARNINGS PER SHARE (Tables)

EARNINGS PER SHARE (Tables)	6 Months Ended
	Jun. 30, 2019
Earnings Per Share [Abstract]
Schedule of the computation of basic and diluted earnings per common share	The following table sets forth the computation of basic and diluted earnings (loss) per common share for the three and six months ended June 30, 2019 and 2018 , (in thousands, except per share amounts): Three Months Ended Six Months Ended 2019 2018 2019 2018 Earnings (loss) per common share - basic and diluted Numerator Net income $ 17,733 $ 13,041 $ 30,673 $ 25,014 Net income attributable to noncontrolling interests (25,389 ) (7,150 ) (30,918 ) (8,663 ) Net (loss) income attributable to National Storage Affiliates Trust (7,656 ) 5,891 (245 ) 16,351 Distributions to preferred shareholders (3,257 ) (2,587 ) (5,845 ) (5,175 ) Distributed and undistributed earnings allocated to participating securities (9 ) (7 ) (18 ) (14 ) Net (loss) income attributable to common shareholders - basic $ (10,922 ) $ 3,297 $ (6,108 ) $ 11,162 Effect of assumed conversion of dilutive securities — — — 8,356 Net (loss) income attributable to common shareholders - diluted $ (10,922 ) $ 3,297 $ (6,108 ) $ 19,518 Denominator Weighted average shares outstanding - basic 57,543 50,486 57,101 50,393 Effect of dilutive securities: Weighted average OP units outstanding — — — 29,060 Weighted average DownREIT OP unit equivalents outstanding — — — 1,835 Weighted average LTIP units outstanding — — — 323 Weighted average subordinated performance units and DownREIT subordinated performance unit equivalents — — — 18,881 Weighted average shares outstanding - diluted 57,543 50,486 57,101 100,492 Earnings (loss) per share - basic $ (0.19 ) $ 0.07 $ (0.11 ) $ 0.22 Earnings (loss) per share - diluted $ (0.19 ) $ 0.07 $ (0.11 ) $ 0.19

FAIR VALUE MEASUREMENTS (Tables

FAIR VALUE MEASUREMENTS (Tables)	6 Months Ended
	Jun. 30, 2019
Fair Value Disclosures [Abstract]
Schedule of interest rate swap derivatives measured at fair value	Information regarding the Company's interest rate swaps measured at fair value, which are classified within Level 2 of the GAAP fair value hierarchy, is presented below (dollars in thousands): Fair value at December 31, 2017 $ 12,414 Gains on interest rate swaps reclassified into interest expense from accumulated other comprehensive income (232 ) Unrealized gains on interest rate swaps included in accumulated other comprehensive income 13,655 Fair value at June 30, 2018 $ 25,837 Fair value at December 31, 2018 $ 14,195 Gains on interest rate swaps reclassified into interest expense from accumulated other comprehensive income (2,553 ) Unrealized losses on interest rate swaps included in accumulated other comprehensive income (27,114 ) Fair value at June 30, 2019 $ (15,472 )

LEASES (Tables)

LEASES (Tables)	6 Months Ended
	Jun. 30, 2019
Leases [Abstract]
Schedule of weighted-average remaining lease terms and weighted-average discount rates	The weighted-average remaining lease term and the weighted-average discount rate for the Company's operating leases as of June 30, 2019 are as follows: June 30, 2019 Weighted-average remaining lease term Real estate leasehold interests 29 years Office leases 7 years Weighted-average remaining discount rate Real estate leasehold interests 4.9 % Office leases 4.1 %
Schedule of Future Minimum Lease Payments Under Operating Leases	As of June 30, 2019 , the future minimum lease payments under the Company's operating leases, for which the Company is a lessee, are as follows (in thousands): Year Ending December 31, Real Estate Leasehold Interests Office Leases Total Remainder of 2019 $ 670 $ 116 $ 786 2020 1,385 286 1,671 2021 1,410 387 1,797 2022 1,425 381 1,806 2023 1,431 346 1,777 2024 through 2092 36,728 1,043 37,771 Total lease payments $ 43,049 $ 2,559 $ 45,608 Less imputed interest (21,091 ) (365 ) (21,456 ) Total $ 21,958 $ 2,194 $ 24,152
Schedule of Future Minimum Lease Payments Under Operating Leases at Prior Year	As of December 31, 2018, the future minimum lease payments under the Company's operating leases, for which the Company is a lessee, are as follows (in thousands): Year Ending December 31, Real Estate Leasehold Interests Office Leases Total Remainder of 2019 $ 1,334 $ 345 $ 1,679 2020 1,379 398 1,777 2021 1,404 387 1,791 2022 1,419 381 1,800 2023 1,424 346 1,770 2024 through 2092 36,074 1,073 37,147 Total lease payments $ 43,034 $ 2,930 $ 45,964

ORGANIZATION AND NATURE OF OP_2

ORGANIZATION AND NATURE OF OPERATIONS (Details) ft² in Millions	Jun. 30, 2019ft²storage_unitstateproperty
Schedule of Equity Method Investments [Line Items]
Number of self storage properties | property	729
Number of states in which self storage properties are located | state	35
Total rentable square feet in self storage properties | ft²	46.5
Number of storage units | storage_unit	373,000
Consolidated Properties
Schedule of Equity Method Investments [Line Items]
Number of self storage properties | property	554
Number of states in which self storage properties are located | state	29
Total rentable square feet in self storage properties | ft²	33.8
Number of storage units | storage_unit	269,000
Unconsolidated Properties | Corporate Joint Venture
Schedule of Equity Method Investments [Line Items]
Number of self storage properties | property	175
Number of states in which self storage properties are located | state	21
Total rentable square feet in self storage properties | ft²	12.7
Number of storage units | storage_unit	104,000
Company's equity interest in unconsolidated real estate ventures (percent)	25.00%

SUMMARY OF SIGNIFICANT ACCOUN_3

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Narrative (Details) $ in Thousands	Jun. 30, 2019USD ($)partnershipproperty	Dec. 31, 2018USD ($)partnershipproperty
Variable Interest Entity [Line Items]
Number of self storage properties | property	729
Net book value of real estate owned	$ 2,725,663	$ 2,391,462
Carrying value of fixed rate mortgages	1,470,101	1,277,638
Mortgages | Fixed rate mortgages payable
Variable Interest Entity [Line Items]
Carrying value of fixed rate mortgages	$ 265,601	$ 268,138
VIE, Primary Beneficiary
Variable Interest Entity [Line Items]
Number of partnerships considered to be VIEs | partnership	21	21
Number of self storage properties | property	34	34
Net book value of real estate owned	$ 236,800	$ 240,400
VIE, Primary Beneficiary | Mortgages | Fixed rate mortgages payable
Variable Interest Entity [Line Items]
Carrying value of fixed rate mortgages	$ 137,400	$ 138,400

SUMMARY OF SIGNIFICANT ACCOUN_4

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Revenue Recognition (Details)	3 Months Ended			4 Months Ended	6 Months Ended
	Jun. 30, 2019USD ($)property	Jun. 30, 2018USD ($)	Dec. 31, 2016USD ($)property	Dec. 31, 2018USD ($)	Jun. 30, 2019USD ($)property	Jun. 30, 2018USD ($)
Disaggregation of Revenue [Line Items]
Number of self storage properties | property	729				729
Initial term of unconsolidated real estate venture agreements					4 years
Performance obligation period of recognition					4 years
Corporate Joint Venture | 2016 Joint Venture
Disaggregation of Revenue [Line Items]
Number of self storage properties | property			66
Tenant Insurance and Tenant Warranty Protection Plan Revenues
Disaggregation of Revenue [Line Items]
Revenue	$ 2,200,000	$ 1,800,000			$ 4,300,000	$ 3,500,000
Retail Products and Supplies
Disaggregation of Revenue [Line Items]
Revenue	500,000	400,000			900,000	800,000
Property Management, Call Center, and Platform Fees
Disaggregation of Revenue [Line Items]
Revenue	3,200,000	1,400,000			$ 6,400,000	2,700,000
Property management fees as percent of monthly gross revenues and net sales revenue of unconsolidated real estate venture assets					6.00%
Platform fees per unconsolidated real estate venture property per month					$ 1,250
Call center fees as percent of monthly gross revenues and net sales revenue of unconsolidated real estate venture assets					1.00%
Acquisition Fees
Disaggregation of Revenue [Line Items]
Revenue	500,000	300,000			$ 1,000,000	600,000
Acquisition fee			$ 4,100,000	$ 4,000,000
Acquisition fees received as a percent of gross capitalization of Initial 2016 JV Portfolio			0.65%
Deferred revenue	3,700,000			$ 4,600,000	3,700,000
Tenant Warranty Protection or Tenant Insurance
Disaggregation of Revenue [Line Items]
Revenue	$ 1,200,000	$ 500,000			$ 2,400,000	$ 1,000,000
Percent of total warranty protection plan proceeds received per unconsolidated real estate venture property (percent)					50.00%

SHAREHOLDERS' EQUITY AND NONC_3

SHAREHOLDERS' EQUITY AND NONCONTROLLING INTERESTS - Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Class of Stock [Line Items]
Common and preferred shares, shares authorized under ATM program	$ 250,000
Common shares of beneficial interest, par value (in dollars per share)	$ 0.01		$ 0.01
Preferred share/unit dividend rate (percent)	6.00%
Proceeds from issuance of common shares	$ 70,637	$ 0
Proceeds from issuance of preferred shares	$ 43,624	$ 0
Series A-1 preferred units stated value (in dollars per share)	$ 0.01		$ 0.01
Series A-1 preferred units | NSA OP, LP
Class of Stock [Line Items]
Preferred share/unit dividend rate (percent)	6.00%
Series A-1 preferred units stated value (in dollars per share)	$ 25
Unit conversion ratio	1
OP units | NSA OP, LP
Class of Stock [Line Items]
Issuance of shares/units (in shares)	863,148
Unit conversion ratio	1
Minimum conversion period (in years)	1 year
Redemptions/conversions of units (in shares)	254,528
OP units | NSA OP, LP | Self Storage Properties
Class of Stock [Line Items]
Issuance of shares/units (in shares)	343,657
OP units | DownREIT Partnership
Class of Stock [Line Items]
Issuance of shares/units (in shares)	13,475
Unit conversion ratio	1
Minimum conversion period (in years)	5 years
Subordinated performance units
Class of Stock [Line Items]
Percentage of cash available for distribution used in conversion ratio calculation	110.00%
Subordinated performance units | NSA OP, LP
Class of Stock [Line Items]
Redemptions/conversions of units (in shares)	913,680
Unit conversion, lock out period (in years)	2 years
Subordinated performance units | NSA OP, LP | Self Storage Properties
Class of Stock [Line Items]
Issuance of shares/units (in shares)	1,096,840
Subordinated performance units | DownREIT Partnership
Class of Stock [Line Items]
Unit conversion ratio	1
Minimum conversion period (in years)	5 years
Redemptions/conversions of units (in shares)	15,377
LTIP units | NSA OP, LP
Class of Stock [Line Items]
Issuance of shares/units (in shares)	204,213
Unit conversion ratio	1
Conversion of LTIP units into OP units (in shares)	379,617
Par value of common shares of beneficial interest (in dollars per share) | At the Market Program [Member]
Class of Stock [Line Items]
Issuance of shares/units (in shares)	2,375,000
Average offering price (in dollars per share)	$ 30.06
Proceeds from issuance of common shares	$ 70,600
Series A preferred shares | At the Market Program [Member]
Class of Stock [Line Items]
Issuance of shares/units (in shares)	1,785,680
Average offering price (in dollars per share)	$ 24.84
Proceeds from issuance of preferred shares	$ 43,600
Acquisition of Interest in Reinsurance Company | OP units | NSA OP, LP
Class of Stock [Line Items]
Issuance of shares/units (in shares)	285,512

SHAREHOLDERS' EQUITY AND NONC_4

SHAREHOLDERS' EQUITY AND NONCONTROLLING INTERESTS - Equity Interests (Details) - shares	Jun. 30, 2019	Dec. 31, 2018
Partnership Subsidiaries [Member]
Noncontrolling Interest [Line Items]
Outstanding equity interest (in shares)	49,084,715	47,120,753
Series A-1 preferred units | NSA OP, LP
Noncontrolling Interest [Line Items]
Outstanding equity interest (in shares)	684,421	343,719
OP units | NSA OP, LP
Noncontrolling Interest [Line Items]
Outstanding equity interest (in shares)	30,491,509	28,874,103
OP units | DownREIT Partnership
Noncontrolling Interest [Line Items]
Outstanding equity interest (in shares)	1,848,261	1,834,786
Subordinated performance units | NSA OP, LP
Noncontrolling Interest [Line Items]
Outstanding equity interest (in shares)	10,932,635	10,749,475
Subordinated performance units | DownREIT Partnership
Noncontrolling Interest [Line Items]
Outstanding equity interest (in shares)	4,371,622	4,386,999
LTIP units | NSA OP, LP
Noncontrolling Interest [Line Items]
Outstanding equity interest (in shares)	756,267	931,671

SELF STORAGE PROPERTIES (Detail

SELF STORAGE PROPERTIES (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Real Estate [Abstract]
Land	$ 640,052		$ 640,052		$ 583,455
Buildings and improvements	2,369,152		2,369,152		2,048,281
Furniture and equipment	6,345		6,345		5,987
Total self storage properties	3,015,549		3,015,549		2,637,723
Less accumulated depreciation	(289,886)		(289,886)		(246,261)
Self storage properties, net	2,725,663		2,725,663		$ 2,391,462
Depreciation expense related to self storage properties	$ 22,700	$ 18,900	$ 44,200	$ 36,900

INVESTMENT IN UNCONSOLIDATED _3

INVESTMENT IN UNCONSOLIDATED REAL ESTATE VENTURES - Narrative (Details) ft² in Millions, $ in Millions	6 Months Ended
	Jun. 30, 2019USD ($)ft²storage_unitstateproperty	Dec. 31, 2016property
Schedule of Equity Method Investments [Line Items]
Number of self storage properties	729
Rentable square feet in self storage properties | ft²	46.5
Number of storage units | storage_unit	373,000
Number of states in which self storage properties are located | state	35
Number of self storage properties sold	1
Gross selling price of self storage properties sold | $	$ 6.5
Corporate Joint Venture | 2016 Joint Venture
Schedule of Equity Method Investments [Line Items]
Number of self storage properties		66
Unconsolidated Properties | Corporate Joint Venture
Schedule of Equity Method Investments [Line Items]
Number of self storage properties	175
Rentable square feet in self storage properties | ft²	12.7
Number of storage units | storage_unit	104,000
Number of states in which self storage properties are located | state	21
Unconsolidated Properties | Corporate Joint Venture | 2018 Joint Venture
Schedule of Equity Method Investments [Line Items]
Number of self storage properties	103
Rentable square feet in self storage properties | ft²	7.7
Number of storage units | storage_unit	63,000
Number of states in which self storage properties are located | state	17
Unconsolidated Properties | Corporate Joint Venture | 2016 Joint Venture
Schedule of Equity Method Investments [Line Items]
Number of self storage properties	72
Rentable square feet in self storage properties | ft²	4.9
Number of storage units | storage_unit	40,000
Number of states in which self storage properties are located | state	13
Number of self storage properties sold	1
Gross selling price of self storage properties sold | $	$ 4.1

INVESTMENT IN UNCONSOLIDATED _4

INVESTMENT IN UNCONSOLIDATED REAL ESTATE VENTURES - Condensed Financial Position (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
ASSETS
Self storage properties, net	$ 1,863,002	$ 1,894,412
Other assets	29,489	50,915
Total assets	1,892,491	1,945,327
LIABILITIES AND EQUITY
Debt financing	947,493	956,357
Other liabilities	19,973	16,516
Equity	925,025	972,454
Total liabilities and equity	$ 1,892,491	$ 1,945,327

INVESTMENT IN UNCONSOLIDATED _5

INVESTMENT IN UNCONSOLIDATED REAL ESTATE VENTURES - Condensed Operating Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Equity Method Investments and Joint Ventures [Abstract]
Total revenue	$ 40,858	$ 15,196	$ 80,653	$ 30,002
Property operating expenses	12,544	5,000	25,088	10,293
Net operating income	28,314	10,196	55,565	19,709
Supervisory, administrative and other expenses	(2,706)	(1,072)	(5,359)	(2,129)
Depreciation and amortization	(21,888)	(5,527)	(43,714)	(11,034)
Interest expense	(9,941)	(2,928)	(19,961)	(5,827)
Loss on sale of self storage properties			(806)	0
Acquisition and other expenses	(419)	(275)	(827)	(537)
Net (loss) income	$ (6,640)	$ 394	$ (15,102)	$ 182

SELF STORAGE PROPERTY ACQUISI_3

SELF STORAGE PROPERTY ACQUISITIONS AND DISPOSITIONS - Narrative (Details) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019USD ($)property	Mar. 31, 2019property	Jun. 30, 2019USD ($)property
Business Acquisition [Line Items]
Number of self storage properties sold			1
Acquisition-related costs capitalized			$ 2.6
Recognized fair value allocated to real estate	$ 370.7		370.7
Gross selling price of self storage properties sold	6.5		6.5
Gain (loss) on disposal of self storage properties			2.8
Customer In-Place Leases
Business Acquisition [Line Items]
Recognized fair value allocated to intangible assets	9.2		$ 9.2
Affiliated Entity | Participating Regional Operator (PRO)
Business Acquisition [Line Items]
Number of properties acquired | property			21
Estimated fair value of acquired self storage properties	145.5		$ 145.5
Corporate Joint Venture | 2016 Joint Venture
Business Acquisition [Line Items]
Number of properties acquired | property			1
Estimated fair value of acquired self storage properties	$ 4.1		$ 4.1
2019 Acquisitions
Business Acquisition [Line Items]
Number of properties acquired | property	24	32	56
Estimated fair value of acquired self storage properties	$ 379.9		$ 379.9

SELF STORAGE PROPERTY ACQUISI_4

SELF STORAGE PROPERTY ACQUISITIONS AND DISPOSITIONS - Acquisitions (Details) - 2019 Acquisitions $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019USD ($)property	Mar. 31, 2019USD ($)property	Jun. 30, 2019USD ($)property
Business Acquisition [Line Items]
Number of Properties | property	24	32	56
Cash and Acquisition Costs	$ 168,442	$ 160,531	$ 328,973
Value of OP equity	15,515	33,356	48,871
Other Liabilities	1,378	674	2,052
Total	$ 185,335	$ 194,561	$ 379,896

OTHER ASSETS (Details)

OTHER ASSETS (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Receivables:
Trade, net	$ 3,374		$ 3,374		$ 3,402
PROs and other affiliates	1,664		1,664		2,027
Receivables from unconsolidated real estate ventures	4,454		4,454		4,573
Property acquisition and other deposits	275		275		20,977
Interest rate swaps	2,186		2,186		16,164
Prepaid expenses and other	5,444		5,444		4,266
Corporate furniture, equipment and other, net	1,704		1,704		1,574
Goodwill	5,750		5,750		5,750
Total	59,363		59,363		75,053
Customer In-Place Leases
Finite-Lived Intangible Assets [Line Items]
Amortization expense	2,800	$ 3,300	5,300	$ 6,300
Accumulated amortization	5,568		5,568		5,090
Receivables:
Finite-lived intangible	8,029		8,029		4,063
Trade Name
Receivables:
Trade name	3,200		3,200		3,200
Management Contract
Finite-Lived Intangible Assets [Line Items]
Amortization expense	200	$ 200	400	$ 400
Accumulated amortization	1,918		1,918		1,564
Receivables:
Finite-lived intangible	8,703		8,703		9,057
Tenant reinsurance intangible
Finite-Lived Intangible Assets [Line Items]
Amortization expense	100		100
Accumulated amortization	100		100		0
Receivables:
Finite-lived intangible	$ 14,580		$ 14,580		$ 0

DEBT FINANCING - Debt Summary (

DEBT FINANCING - Debt Summary (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Apr. 24, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Effective interest rate (percent)		4.27%
Debt, principal amount	$ 1,470,101		$ 1,277,638
Unamortized debt issuance costs and debt premium, net	(454)		464
Total debt	$ 1,469,647		1,278,102
Line of Credit | Credit Facility | Revolving line of credit
Debt Instrument [Line Items]
Effective interest rate (percent)	3.80%
Debt, principal amount	$ 234,500		139,500
Unsecured Debt | Credit Facility | Term loan A
Debt Instrument [Line Items]
Effective interest rate (percent)	2.91%
Debt, principal amount	$ 235,000		235,000
Unsecured Debt | Credit Facility | Term loan B
Debt Instrument [Line Items]
Effective interest rate (percent)	2.94%
Debt, principal amount	$ 155,000		155,000
Unsecured Debt | Credit Facility | Term loan C
Debt Instrument [Line Items]
Effective interest rate (percent)	3.71%
Debt, principal amount	$ 105,000		105,000
Unsecured Debt | Credit Facility | Term loan D
Debt Instrument [Line Items]
Effective interest rate (percent)	3.79%
Debt, principal amount	$ 125,000		125,000
Unsecured Debt | 2023 Term loan facility
Debt Instrument [Line Items]
Effective interest rate (percent)	2.83%
Debt, principal amount	$ 175,000		175,000
Unsecured Debt | 2028 Term loan facility
Debt Instrument [Line Items]
Effective interest rate (percent)	4.62%
Debt, principal amount	$ 75,000		75,000
Unsecured Debt | 2029 Term loan facility
Debt Instrument [Line Items]
Effective interest rate (percent)	4.27%
Debt, principal amount	$ 100,000		0
Mortgages | Fixed rate mortgages payable
Debt Instrument [Line Items]
Effective interest rate (percent)	4.18%
Debt, principal amount	$ 265,601		$ 268,138

DEBT FINANCING - Future maturit

DEBT FINANCING - Future maturities (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Scheduled Principal and Maturity Payments
2019	$ 2,590
2020	273,897
2021	242,603
2022	159,205
2023	377,049
2024	126,964
Thereafter	287,793
Total principal	1,470,101	$ 1,277,638
Amortization of Premium and Unamortized Debt Issuance Costs
2019	(239)
2020	(816)
2021	(894)
2022	(556)
2023	(166)
2024	162
Thereafter	2,055
Total premium amortization and unamortized debt issuance costs	(454)	464
Total
2019	2,351
2020	273,081
2021	241,709
2022	158,649
2023	376,883
2024	127,126
Thereafter	289,848
Total debt	$ 1,469,647	$ 1,278,102

DEBT FINANCING - Narrative (Det

DEBT FINANCING - Narrative (Details) - USD ($)	Jul. 29, 2019	Jun. 30, 2019	Jul. 30, 2019	Apr. 24, 2019
Debt Instrument [Line Items]
Notional amount				$ 100,000,000
Effective interest rate (percent)				4.27%
Letter of credit
Debt Instrument [Line Items]
Letters of credit outstanding		$ 5,700,000
Unsecured Debt | Credit Facility
Debt Instrument [Line Items]
Maximum borrowing capacity		1,020,000,000
Maximum borrowing capacity if expansion option is exercised		1,300,000,000
Unsecured Debt | Credit Facility | Term loan A
Debt Instrument [Line Items]
Maximum borrowing capacity		$ 235,000,000
Effective interest rate (percent)		2.91%
Unsecured Debt | Credit Facility | Term loan B
Debt Instrument [Line Items]
Maximum borrowing capacity		$ 155,000,000
Effective interest rate (percent)		2.94%
Unsecured Debt | Credit Facility | Term loan C
Debt Instrument [Line Items]
Maximum borrowing capacity		$ 105,000,000
Effective interest rate (percent)		3.71%
Unsecured Debt | Credit Facility | Term loan D
Debt Instrument [Line Items]
Maximum borrowing capacity		$ 125,000,000
Effective interest rate (percent)		3.79%
Unsecured Debt | Amended Credit Facility | Subsequent Event
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 1,275,000,000
Maximum borrowing capacity if expansion option is exercised	1,750,000,000
Amended credit facility total borrowing capacity increase	255,000,000
Unsecured Debt | Amended Credit Facility | Term loan A | Subsequent Event
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 125,000,000
Effective interest rate (percent)	3.74%
Unsecured Debt | Amended Credit Facility | Term loan B | Subsequent Event
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 250,000,000
Effective interest rate (percent)	2.91%
Unsecured Debt | Amended Credit Facility | Term loan C | Subsequent Event
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 225,000,000
Effective interest rate (percent)	2.80%
Unsecured Debt | Amended Credit Facility | Term loan D | Subsequent Event
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 175,000,000
Effective interest rate (percent)	3.57%
Unsecured Debt | 2029 Term loan facility
Debt Instrument [Line Items]
Debt instrument, face amount				$ 100,000,000
Effective interest rate (percent)		4.27%
Unsecured Debt | 2029 Senior Notes | Subsequent Event
Debt Instrument [Line Items]
Debt instrument, face amount			$ 100,000,000
Long-term debt, percentage bearing fixed interest, percentage rate			3.98%
Unsecured Debt | 2031 Senior Notes | Subsequent Event
Debt Instrument [Line Items]
Debt instrument, face amount			$ 50,000,000
Long-term debt, percentage bearing fixed interest, percentage rate			4.08%
Line of Credit | Credit Facility | Revolving line of credit
Debt Instrument [Line Items]
Maximum borrowing capacity		$ 400,000,000
Revolving line of credit remaining borrowing capacity		$ 159,800,000
Effective interest rate (percent)		3.80%
Line of Credit | Amended Credit Facility | Revolving line of credit | Subsequent Event
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 500,000,000
Revolving line of credit remaining borrowing capacity	395,500,000
Line of Credit | Amended Credit Facility | Letter of credit | Subsequent Event
Debt Instrument [Line Items]
Letters of credit outstanding	$ 5,700,000
Fed Funds Rate | Unsecured Debt | Amended Credit Facility | Subsequent Event
Debt Instrument [Line Items]
Basis spread on variable rate (percent)	0.50%
Fed Funds Rate | Unsecured Debt | 2029 Term loan facility
Debt Instrument [Line Items]
Basis spread on variable rate (percent)		0.50%
LIBOR | Unsecured Debt | Amended Credit Facility | Subsequent Event
Debt Instrument [Line Items]
Basis spread on variable rate (percent)	1.00%
LIBOR | Unsecured Debt | 2029 Term loan facility
Debt Instrument [Line Items]
Basis spread on variable rate (percent)		1.00%
Minimum | LIBOR | Unsecured Debt | Amended Credit Facility | Subsequent Event
Debt Instrument [Line Items]
Leverage based margin threshold (percent)	1.15%
Elective leverage based margin threshold (percent)	0.78%
Minimum | LIBOR | Unsecured Debt | 2029 Term loan facility
Debt Instrument [Line Items]
Leverage based margin threshold (percent)		1.85%
Elective leverage based margin threshold (percent)		1.40%
Minimum | Base Rate | Unsecured Debt | Amended Credit Facility | Subsequent Event
Debt Instrument [Line Items]
Leverage based margin threshold (percent)	0.15%
Elective leverage based margin threshold (percent)	0.00%
Minimum | Base Rate | Unsecured Debt | 2029 Term loan facility
Debt Instrument [Line Items]
Leverage based margin threshold (percent)		0.85%
Elective leverage based margin threshold (percent)		0.40%
Maximum | LIBOR | Unsecured Debt | Amended Credit Facility | Subsequent Event
Debt Instrument [Line Items]
Leverage based margin threshold (percent)	2.20%
Elective leverage based margin threshold (percent)	2.25%
Maximum | LIBOR | Unsecured Debt | 2029 Term loan facility
Debt Instrument [Line Items]
Leverage based margin threshold (percent)		2.30%
Elective leverage based margin threshold (percent)		2.25%
Maximum | Base Rate | Unsecured Debt | Amended Credit Facility | Subsequent Event
Debt Instrument [Line Items]
Leverage based margin threshold (percent)	1.20%
Elective leverage based margin threshold (percent)	1.25%
Maximum | Base Rate | Unsecured Debt | 2029 Term loan facility
Debt Instrument [Line Items]
Leverage based margin threshold (percent)		1.30%
Elective leverage based margin threshold (percent)		1.25%

EARNINGS PER SHARE - Basic and

EARNINGS PER SHARE - Basic and Diluted Earnings per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018
Numerator
Net income	$ 17,733	$ 12,940	$ 13,041	$ 11,973	$ 30,673	$ 25,014
Net income attributable to noncontrolling interests	(25,389)		(7,150)		(30,918)	(8,663)
Net (loss) income attributable to National Storage Affiliates Trust	(7,656)		5,891		(245)	16,351
Distributions to preferred shareholders	(3,257)		(2,587)		(5,845)	(5,175)
Distributed and undistributed earnings allocated to participating securities	(9)		(7)		(18)	(14)
Net (loss) income attributable to common shareholders - basic	(10,922)		3,297		(6,108)	11,162
Effect of assumed conversion of dilutive securities	0		0		0	8,356
Net (loss) income attributable to common shareholders - diluted	$ (10,922)		$ 3,297		$ (6,108)	$ 19,518
Denominator
Weighted average shares outstanding - basic	57,543		50,486		57,101	50,393
Effect of dilutive securities:
Weighted average shares outstanding - diluted	57,543		50,486		57,101	100,492
Earnings (loss) per share - basic	$ (0.19)		$ 0.07		$ (0.11)	$ 0.22
Earnings (loss) per share - diluted	$ (0.19)		$ 0.07		$ (0.11)	$ 0.19
OP units | NSA OP, LP
Effect of dilutive securities:
Effect of dilutive securities	0		0		0	29,060
OP units | DownREIT Partnership
Effect of dilutive securities:
Effect of dilutive securities	0		0		0	1,835
LTIP units | NSA OP, LP
Effect of dilutive securities:
Effect of dilutive securities	0		0		0	323
Subordinated performance units | NSA OP, LP And DownREIT Partnership
Effect of dilutive securities:
Effect of dilutive securities	0		0		0	18,881

EARNINGS PER SHARE - Narrative

EARNINGS PER SHARE - Narrative (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2019shares	Jun. 30, 2018shares	Jun. 30, 2019shares
NSA OP, LP | OP units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Unit conversion ratio			1
Minimum conversion period (in years)			1 year
DownREIT Partnership | OP units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Unit conversion ratio			1
Minimum conversion period (in years)			5 years
DownREIT Partnership | Subordinated performance units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Unit conversion ratio			1
Minimum conversion period (in years)			5 years
NSA OP, LP And DownREIT Partnership | Subordinated performance units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Unit conversion ratio			1
Minimum conversion period (in years)			2 years
Long-Term Incentive Plan Unit based on service or market condition
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Weighted average outstanding equity interests excluded from computation of diluted earnings per share (in units)			448,089
Long-Term Incentive Plan Unit based on future acquisitions
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Weighted average outstanding equity interests excluded from computation of diluted earnings per share (in units)			224,000
OP units, DownREIT OP units, Subordinated performance units, DownREIT subordinated performance units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Weighted average outstanding equity interests excluded from computation of diluted earnings per share (in units)	54,000,000	50,600,000	53,200,000

RELATED PARTY TRANSACTIONS (Det

RELATED PARTY TRANSACTIONS (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Jun. 01, 2019
Related Party Transaction [Line Items]
Payroll and related costs reimbursed to the PROs by the Company		$ 27,190	$ 25,184	$ 53,647	$ 50,410
Ownership interest in reinsurance company acquired (percent)						5.50%
Equity interest in reinsurance company	$ 500	500		500
Supervisory and Administrative Fee Agreement | Management | Participating Regional Operator (PRO)
Related Party Transaction [Line Items]
Supervisory and administrative fees paid to the PROs		4,900	4,200	$ 9,600	8,200
Supervisory and Administrative Fee Agreement | Management | Participating Regional Operator (PRO) | Minimum
Related Party Transaction [Line Items]
Supervisory and administrative fee agreement of gross revenue, percent				5.00%
Supervisory and Administrative Fee Agreement | Management | Participating Regional Operator (PRO) | Maximum
Related Party Transaction [Line Items]
Supervisory and administrative fee agreement of gross revenue, percent				6.00%
Payroll Services | Management | Participating Regional Operator (PRO)
Related Party Transaction [Line Items]
Payroll and related costs reimbursed to the PROs by the Company		7,900	7,200	$ 15,700	14,500
Due Diligence Costs | Management | Participating Regional Operator (PRO)
Related Party Transaction [Line Items]
Due diligence expenses payable to the PROs		300	$ 100	$ 600	$ 300
Real Estate Purchases | Corporate Joint Venture
Related Party Transaction [Line Items]
Number of properties acquired				1
Consideration in acquisition transaction				$ 4,100
Acquisition of Interest in Reinsurance Company
Related Party Transaction [Line Items]
Consideration in acquisition transaction	15,100
Cash paid in acquisition	6,600
Acquisition of Interest in Reinsurance Company | Management
Related Party Transaction [Line Items]
Cash paid in acquisition	2,200
Tenant reinsurance intangible
Related Party Transaction [Line Items]
Recognized fair value allocated to intangible assets	$ 14,600	$ 14,600		$ 14,600
Weighted average remaining useful life (in years)				25 years
OP units | NSA OP, LP | Acquisition of Interest in Reinsurance Company
Related Party Transaction [Line Items]
OP units issued in acquisition (in shares)	285,512
Value of OP units issued in acquisition	$ 8,500
OP units | NSA OP, LP | Acquisition of Interest in Reinsurance Company | Management
Related Party Transaction [Line Items]
OP units issued in acquisition (in shares)	95,170
Value of OP units issued in acquisition	$ 2,800

FAIR VALUE MEASUREMENTS - Inter

FAIR VALUE MEASUREMENTS - Interest Swap Derivatives (Details) - Interest Rate Swap - Level 2 - Designated as Hedging Instrument - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis [Roll Forward]
Fair value at beginning of period	$ 14,195	$ 12,414
(Gains) losses on interest rate swaps reclassified into interest expense from accumulated other comprehensive income	(2,553)	(232)
Unrealized gains (losses) on interest rate swaps included in accumulated other comprehensive income	(27,114)	13,655
Fair value of end of period	$ (15,472)	$ 25,837

FAIR VALUE MEASUREMENTS - Narra

FAIR VALUE MEASUREMENTS - Narrative (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Apr. 24, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notional amount			$ 100
Unrealized gains forecasted to be included in earnings transferred from AOCI in the next twelve months	$ (0.6)
Level 2 | Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed rate mortgages, fair value disclosure	$ 283			$ 276.5
Weighted average market interest rate (percent)	3.39%	4.17%
Weighted average contractual interest rate (percent)	4.84%	4.85%
Designated as Hedging Instrument | Interest Rate Swap
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Notional amount	$ 970			795
Weighted average remaining term	4 years 7 months 6 days
Weighted average fixed rate (percent)	1.92%
Reported Value Measurement
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fixed rate mortgages, fair value disclosure	$ 265.6			$ 268.1

LEASES - Narrative (Details)

LEASES - Narrative (Details) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019USD ($)	Jun. 30, 2018USD ($)	Jun. 30, 2019USD ($)	Jun. 30, 2018USD ($)
Real Estate Leasehold Interest
Lessee, Lease, Description [Line Items]
Number of properties subject to non-cancelable leasehold interest agreements			7
Rent expense	$ 0.4	$ 0.4	$ 0.8	$ 0.8
Real Estate Leasehold Interest | Minimum
Lessee, Lease, Description [Line Items]
Operating leases, term (in years)	15 years		15 years
Real Estate Leasehold Interest | Maximum
Lessee, Lease, Description [Line Items]
Operating leases, term (in years)	73 years		73 years
Office Leases
Lessee, Lease, Description [Line Items]
Rent expense	$ 0.1	$ 0.1	$ 0.2	$ 0.1
Office Leases | Minimum
Lessee, Lease, Description [Line Items]
Operating leases, term (in years)	3 years		3 years
Office Leases | Maximum
Lessee, Lease, Description [Line Items]
Operating leases, term (in years)	7 years		7 years

LEASES - Weighted-Average Remai

LEASES - Weighted-Average Remaining Term and Weighted-Average Discount Rate (Details)	Jun. 30, 2019
Real Estate Leasehold Interest
Lessee, Lease, Description [Line Items]
Weighted-average remaining lease term	29 years
Weighted-average remaining discount rate	4.90%
Office Leases
Lessee, Lease, Description [Line Items]
Weighted-average remaining lease term	7 years
Weighted-average remaining discount rate	4.10%

LEASES - Future Minimum Lease P

LEASES - Future Minimum Lease Payments Under Operating Leases (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018	Jun. 30, 2018
Future Minimum Lease Payments
Remainder of 2019	$ 786
2020	1,671
2021	1,797
2022	1,806
2023	1,777
2024 through 2092	37,771
Total lease payments	45,608
Less imputed interest	(21,456)
Operating lease liabilities	24,152	$ 0	$ 0
Future Minimum Lease Payments, Prior Year End
Remainder of 2019		1,679
2020		1,777
2021		1,791
2022		1,800
2023		1,770
2024 through 2092		37,147
Total lease payments		45,964
Real Estate Leasehold Interest
Future Minimum Lease Payments
Remainder of 2019	670
2020	1,385
2021	1,410
2022	1,425
2023	1,431
2024 through 2092	36,728
Total lease payments	43,049
Less imputed interest	(21,091)
Operating lease liabilities	21,958
Future Minimum Lease Payments, Prior Year End
Remainder of 2019		1,334
2020		1,379
2021		1,404
2022		1,419
2023		1,424
2024 through 2092		36,074
Total lease payments		43,034
Office Leases
Future Minimum Lease Payments
Remainder of 2019	116
2020	286
2021	387
2022	381
2023	346
2024 through 2092	1,043
Total lease payments	2,559
Less imputed interest	(365)
Operating lease liabilities	$ 2,194
Future Minimum Lease Payments, Prior Year End
Remainder of 2019		345
2020		398
2021		387
2022		381
2023		346
2024 through 2092		1,073
Total lease payments		$ 2,930

SUBSEQUENT EVENTS (Details)

SUBSEQUENT EVENTS (Details) - USD ($)	Jul. 29, 2019	Jul. 30, 2019	Jun. 30, 2019	Apr. 24, 2019
Subsequent Event [Line Items]
Effective interest rate (percent)				4.27%
Letter of credit
Subsequent Event [Line Items]
Letters of credit outstanding			$ 5,700,000
Subsequent Event | 2029 Senior Notes | Unsecured Debt
Subsequent Event [Line Items]
Debt instrument, face amount		$ 100,000,000
Long-term debt, percentage bearing fixed interest, percentage rate		3.98%
Subsequent Event | 2031 Senior Notes | Unsecured Debt
Subsequent Event [Line Items]
Debt instrument, face amount		$ 50,000,000
Long-term debt, percentage bearing fixed interest, percentage rate		4.08%
Subsequent Event | Amended Credit Facility
Subsequent Event [Line Items]
Extension fee (percent)	0.075%
Subsequent Event | Amended Credit Facility | Unsecured Debt
Subsequent Event [Line Items]
Amended credit facility total borrowing capacity increase	$ 255,000,000
Maximum borrowing capacity	1,275,000,000
Maximum borrowing capacity if expansion option is exercised	$ 1,750,000,000
Maximum total leverage ratio	60.00%
Maximum total leverage ratio allowable within two quarters of material acquisition	65.00%
Minimum fixed charge ratio	1.5
Maximum unsecured debt to unencumbered asset value ratio	60.00%
Maximum unsecured debt to unencumbered asset value ratio allowable within two quarters of material acquisition	65.00%
Minimum enencumbered adjusted net operating income to unsecured interest expense ratio	2
Subsequent Event | Fed Funds Rate | Amended Credit Facility | Unsecured Debt
Subsequent Event [Line Items]
Basis spread on variable rate (percent)	0.50%
Subsequent Event | LIBOR | Amended Credit Facility | Unsecured Debt
Subsequent Event [Line Items]
Basis spread on variable rate (percent)	1.00%
Subsequent Event | Minimum | LIBOR | Amended Credit Facility | Unsecured Debt
Subsequent Event [Line Items]
Leverage based applicable margin (percent)	1.15%
Credit pricing elective applicable margin (percent)	0.78%
Subsequent Event | Minimum | Base Rate | Amended Credit Facility | Unsecured Debt
Subsequent Event [Line Items]
Leverage based applicable margin (percent)	0.15%
Credit pricing elective applicable margin (percent)	0.00%
Subsequent Event | Maximum | LIBOR | Amended Credit Facility | Unsecured Debt
Subsequent Event [Line Items]
Leverage based applicable margin (percent)	2.20%
Credit pricing elective applicable margin (percent)	2.25%
Subsequent Event | Maximum | Base Rate | Amended Credit Facility | Unsecured Debt
Subsequent Event [Line Items]
Leverage based applicable margin (percent)	1.20%
Credit pricing elective applicable margin (percent)	1.25%
Subsequent Event | Revolving line of credit | Amended Credit Facility | Line of Credit
Subsequent Event [Line Items]
Maximum borrowing capacity	$ 500,000,000
Revolving line of credit remaining borrowing capacity	$ 395,500,000
Subsequent Event | Revolving line of credit | Minimum | Amended Credit Facility
Subsequent Event [Line Items]
Usage based fees with respect to unused portion of Revolver (percent)	0.15%
Ratings based fees if credit pricing elected (percent)	0.125%
Subsequent Event | Revolving line of credit | Maximum | Amended Credit Facility
Subsequent Event [Line Items]
Usage based fees with respect to unused portion of Revolver (percent)	0.20%
Ratings based fees if credit pricing elected (percent)	0.30%
Subsequent Event | Term loan A | Amended Credit Facility | Unsecured Debt
Subsequent Event [Line Items]
Maximum borrowing capacity	$ 125,000,000
Effective interest rate (percent)	3.74%
Subsequent Event | Term loan B | Amended Credit Facility | Unsecured Debt
Subsequent Event [Line Items]
Maximum borrowing capacity	$ 250,000,000
Effective interest rate (percent)	2.91%
Subsequent Event | Term loan C | Amended Credit Facility | Unsecured Debt
Subsequent Event [Line Items]
Maximum borrowing capacity	$ 225,000,000
Effective interest rate (percent)	2.80%
Subsequent Event | Term loan D | Amended Credit Facility | Unsecured Debt
Subsequent Event [Line Items]
Maximum borrowing capacity	$ 175,000,000
Effective interest rate (percent)	3.57%
Subsequent Event | Letter of credit | Amended Credit Facility | Line of Credit
Subsequent Event [Line Items]
Letters of credit outstanding	$ 5,700,000