Qts Realty Trust (QTS) 10-K 26 Feb 21 2020 FY Annual report Financial data

Cover

Cover - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2020	Feb. 22, 2021	Jun. 30, 2020
Document Information [Line Items]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2020
Current Fiscal Year End Date	--12-31
Document Transition Report	false
Entity File Number	001-36109
Entity Registrant Name	QTS Realty Trust, Inc.
Entity Incorporation, State or Country Code	MD
Entity Tax Identification Number	46-2809094
Entity Address, Address Line One	12851 Foster Street
Entity Address, City or Town	Overland Park
Entity Address, State or Province	KS
Entity Address, Postal Zip Code	66213
City Area Code	913
Local Phone Number	312-5503
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
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
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Entity Public Float			$ 3.9
Documents Incorporated by Reference	Portions of the Definitive Proxy Statement for our 2021 Annual Meeting of Stockholders are incorporated by reference into Part III of this report. We expect to file our proxy statement within 120 days after December 31, 2020.
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Entity Central Index Key	0001577368
Amendment Flag	false
Class A Common Stock
Document Information [Line Items]
Title of 12(b) Security	Class A common stock, $.01 par value
Trading Symbol	QTS
Security Exchange Name	NYSE
Entity Common Stock, Shares Outstanding		64,520,050
Class B Common Stock
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		124,995
Series A Redeemable Perpetual Preferred
Document Information [Line Items]
Title of 12(b) Security	Preferred Stock, 7.125% Series A Cumulative Redeemable Perpetual, $0.01 par value
Trading Symbol	QTS.PRA
Security Exchange Name	NYSE
Series B Convertible preferred stock
Document Information [Line Items]
Title of 12(b) Security	Preferred Stock, 6.50% Series B Cumulative Convertible Perpetual, $0.01 par value
Trading Symbol	QTS.PRB
Security Exchange Name	NYSE

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Real Estate Assets
Land	$ 165,109	$ 130,605
Buildings, improvements and equipment	2,839,261	2,178,901
Less: Accumulated depreciation	(702,944)	(558,560)
Total real estate assets	2,301,426	1,750,946
Construction in progress	1,028,765	920,922
Real Estate Assets, net	3,330,191	2,671,868
Investments in unconsolidated entity	22,608	30,218
Operating lease right-of-use assets, net	51,342	57,141
Cash and cash equivalents	22,775	15,653
Rents and other receivables, net	107,563	81,181
Acquired intangibles, net	68,090	81,679
Deferred costs, net	63,689	52,363
Prepaid expenses	10,253	10,586
Goodwill	173,843	173,843
Other assets, net	48,218	49,001
TOTAL ASSETS	3,898,572	3,223,533
LIABILITIES
Unsecured term loans and revolver, net	1,335,241	1,010,640
Senior notes, net of debt issuance costs	492,534	395,549
Finance leases and mortgage notes payable	41,718	46,876
Operating lease liabilities	58,005	64,416
Accounts payable and accrued liabilities	187,270	142,547
Dividends and distributions payable	39,373	34,500
Advance rents, security deposits and other liabilities	19,850	18,027
Derivative liabilities	53,722	26,609
Deferred income taxes	810	749
Deferred income	85,351	39,169
TOTAL LIABILITIES	2,313,874	1,779,082
EQUITY
Additional paid-in capital	1,622,857	1,330,444
Accumulated other comprehensive loss	(50,451)	(24,642)
Accumulated dividends in excess of earnings	(504,313)	(376,002)
Total stockholders’ equity	1,476,174	1,337,817
Noncontrolling interests	108,524	106,634
TOTAL EQUITY	1,584,698	1,444,451
TOTAL LIABILITIES AND EQUITY	3,898,572	3,223,533
Series A Redeemable Perpetual Preferred
EQUITY
Cumulative redeemable perpetual preferred stock	103,212	103,212
Series B Convertible Preferred Units
EQUITY
Cumulative redeemable perpetual preferred stock	304,223	304,223
Common stock
EQUITY
Common stock	$ 646	$ 582

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Series A Redeemable Perpetual Preferred
Dividend rate (as a percent)	7.125%	7.125%
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, liquidation preference (in dollars per share)	$ 25	$ 25
Preferred stock, shares authorized (in shares)	4,600,000	4,600,000
Preferred stock, shares issued (in shares)	4,280,000	4,280,000
Preferred stock, shares outstanding (in shares)	4,280,000	4,280,000
Series B Convertible Preferred Units
Dividend rate (as a percent)	6.50%	6.50%
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, liquidation preference (in dollars per share)	$ 100	$ 100
Preferred stock, shares authorized (in shares)	3,162,500	3,162,500
Preferred stock, shares issued (in shares)	3,162,500	3,162,500
Preferred stock, shares outstanding (in shares)	3,162,500	3,162,500
Common stock
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	450,133,000	450,133,000
Common stock, shares issued (in shares)	64,580,118	58,227,523
Common stock, shares outstanding (in shares)	64,580,118	58,227,523

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Revenues:
Rental	$ 519,858	$ 465,123	$ 413,620
Other	19,510	15,695	36,904
Total revenues	539,368	480,818	450,524
Operating expenses:
Property operating costs	168,497	156,048	148,236
Real estate taxes and insurance	16,020	14,503	12,193
Depreciation and amortization	199,889	168,305	149,891
General and administrative	84,965	80,385	80,857
Transaction, integration, and impairment costs	4,340	15,190	2,743
Restructuring	0	0	37,943
Total operating expenses	473,711	434,431	431,863
(Gain) loss on sale of real estate, net	0	14,769	0
Operating income	65,657	61,156	18,661
Other income and expense:
Interest income	2	111	150
Interest expense	(30,724)	(26,593)	(28,749)
Debt restructuring costs	(18,036)	(1,523)	(605)
Other income (expense)	159	(50)	0
Equity in net loss of unconsolidated entity	(2,044)	(1,473)	0
Income (loss) before taxes	15,014	31,628	(10,543)
Tax benefit (expense)	(438)	37	3,368
Net income (loss)	14,576	31,665	(7,175)
Net (income) loss attributable to noncontrolling interests	1,330	(374)	2,715
Net income (loss) attributable to QTS Realty Trust, Inc.	15,906	31,291	(4,460)
Preferred stock dividends	(28,180)	(28,180)	(16,666)
Net income (loss) attributable to common stockholders	$ (12,274)	$ 3,111	$ (21,126)
Net loss per share attributable to common shares:
Basic (in dollars per share)	$ (0.47)	$ (0.09)	$ (0.44)
Diluted (in dollars per share)	$ (0.47)	$ (0.09)	$ (0.44)
Weighted average Class A common shares outstanding:
Basic (in shares)	60,717,301	54,836,801	50,432,590
Diluted (in shares)	60,717,301	54,836,801	50,432,590

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Net income (loss)	$ 14,576	$ 31,665	$ (7,175)
Other comprehensive income (loss):
Foreign currency translation adjustment gain	187	34	0
Increase (decrease) in fair value of derivative contracts	(28,295)	(29,843)	895
Reclassification of other comprehensive income to utilities expense	1,204	749	0
Reclassification of other comprehensive income to interest expense	10,148	(1,031)	110
Comprehensive income (loss)	(2,180)	1,574	(6,170)
Comprehensive (income) loss attributable to noncontrolling interests	213	(169)	711
Comprehensive income (loss) attributable to QTS Realty Trust, Inc.	$ (1,967)	$ 1,405	$ (5,459)

CONSOLIDATED STATEMENTS OF EQUI

CONSOLIDATED STATEMENTS OF EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	Cumulative Effect, Period of Adoption, Adjustment	Series A Preferred Stock	Series B Preferred Stock	Total stockholders' Equity	Total stockholders' EquityCumulative Effect, Period of Adoption, Adjustment	Total stockholders' EquitySeries A Preferred Stock	Total stockholders' EquitySeries B Preferred Stock	Preferred stock	Preferred stockSeries A Preferred Stock	Preferred stockSeries B Preferred Stock	Common stock	Additional paid-in capital	Accumulated other comprehensive income (loss)	Accumulated dividends in excess of earnings	Accumulated dividends in excess of earningsCumulative Effect, Period of Adoption, Adjustment	Accumulated dividends in excess of earningsSeries A Preferred Stock	Accumulated dividends in excess of earningsSeries B Preferred Stock	Noncontrolling interests
Beginning balance (in shares) at Dec. 31, 2017									0			50,702
Beginning balance at Dec. 31, 2017	$ 990,656				$ 877,414				$ 0			$ 507	$ 1,049,176	$ 1,283	$ (173,552)				$ 113,242
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net share activity through equity award plan (in shares)												421
Net share activity through equity award plan	(1,788)				(2,713)							$ 4	(2,717)						925
Increase (decrease) in fair value of derivative contracts	895				790									790					105
Foreign currency translation adjustments	0
Equity-based compensation expense	18,100				16,014								16,014						2,086
Proceeds net of fees from common equity offering (in shares)										4,280	3,163
Proceeds net of fees from common equity offering			$ 103,212	$ 304,265			$ 103,212	$ 304,265		$ 103,212	$ 304,265
Dividends declared on preferred stock			(6,046)	(10,621)			(6,046)	(10,621)									$ (6,046)	$ (10,621)
Dividends declared to common stockholders	(83,869)				(83,869)										(83,869)
Dividends declared to noncontrolling interests	(10,942)				0														(10,942)
Net income (loss)	(7,175)				(4,460)										(4,460)				(2,715)
Ending balance at Dec. 31, 2018	$ 1,296,687	$ (1,813)			1,193,986	$ (1,813)			$ 407,477			$ 511	1,062,473	2,073	(278,548)	$ (1,813)			102,701
Ending balance (in shares) at Dec. 31, 2018									7,443			51,123
Accounting Standards Update [Extensible List]	us-gaap:AccountingStandardsUpdate201602Member
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net share activity through equity award plan (in shares)												273
Net share activity through equity award plan	$ 1,825				1,819							$ 3	1,816						6
Increase (decrease) in fair value of derivative contracts	(29,843)				(26,745)									(26,745)					(3,098)
Foreign currency translation adjustments	34				30									30					4
Equity-based compensation expense	16,413				14,651								14,651						1,762
Proceeds net of fees from settlement of forward shares (in shares)												2,832
Proceeds net of fees from settlement of forward shares	109,527				102,882							$ 28	102,854						6,645
Adjustment to expenses net from Series B Convertible Preferred stock offering			(42)				(42)			$ (42)
Proceeds net of fees from common equity offering (in shares)												4,000
Proceeds net of fees from common equity offering	158,663				148,690							$ 40	148,650						9,973
Dividends declared on preferred stock			(7,624)	(20,556)			(7,624)	(20,556)									(7,624)	(20,556)
Dividends declared to common stockholders	(98,752)				(98,752)										(98,752)
Dividends declared to noncontrolling interests	(11,733)				0														(11,733)
Net income (loss)	31,665				31,291										31,291				374
Ending balance at Dec. 31, 2019	1,444,451				1,337,817				$ 407,435			$ 582	1,330,444	(24,642)	(376,002)				106,634
Ending balance (in shares) at Dec. 31, 2019									7,443			58,228
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net share activity through equity award plan (in shares)												341
Net share activity through equity award plan	(1,860)				(1,671)							$ 4	(1,675)						(189)
Conversion of Class A Partnership units to Class A common stock (in shares)												100
Conversion of Class A Partnership units to Class A common stock	0				2,290							$ 1	2,289						(2,290)
Increase (decrease) in fair value of derivative contracts	(28,295)				(25,980)									(25,980)					(2,315)
Foreign currency translation adjustments	187				171									171					16
Equity-based compensation expense	26,980				24,353								24,353						2,627
Proceeds net of fees from settlement of forward shares (in shares)												5,911
Proceeds net of fees from settlement of forward shares	285,353				267,505							$ 59	267,446						17,848
Dividends declared on preferred stock			$ (7,624)	$ (20,556)			$ (7,624)	$ (20,556)									$ (7,624)	$ (20,556)
Dividends declared to common stockholders	(116,037)				(116,037)										(116,037)
Dividends declared to noncontrolling interests	(12,477)				0														(12,477)
Net income (loss)	14,576				15,906										15,906				(1,330)
Ending balance at Dec. 31, 2020	$ 1,584,698				$ 1,476,174				$ 407,435			$ 646	$ 1,622,857	$ (50,451)	$ (504,313)				$ 108,524
Ending balance (in shares) at Dec. 31, 2020									7,443			64,580

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOW $ in Thousands	12 Months Ended
	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Cash flow from operating activities:
Net income (loss)	$ 14,576	$ 31,665	$ (7,175)
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization	193,242	160,528	143,354
Amortization of above and below market leases	429	187	465
Amortization of deferred loan costs	4,053	3,877	3,856
Distributions from unconsolidated entity	2,345	3,280	0
Equity in net loss of unconsolidated entity	2,044	1,473	0
Equity-based compensation expense	26,980	16,412	14,972
Bad debt expense (recoveries)	5,036	2,406	(2,275)
(Gain) loss on sale of real estate, net	0	(14,769)	6,994
Loss on extinguishment of debt	14,252	0	0
Write off of deferred loan costs	3,784	1,532	605
Deferred tax expense (benefit)	58	(348)	(2,970)
Integration, impairment & restructuring costs	1,484	11,462	19,575
Foreign currency remeasurement (income) loss	(159)	50	0
Changes in operating assets and liabilities
Rents and other receivables, net	(31,108)	(27,234)	(6,495)
Prepaid expenses	358	(3,406)	(3,063)
Due to/from affiliates, net	2,039	9,284	0
Other assets	(371)	35	4,518
Accounts payable and accrued liabilities	12,324	2,973	8,573
Advance rents, security deposits and other liabilities	2,267	(5,845)	2,069
Deferred income	46,082	5,928	8,270
Net cash provided by operating activities	299,715	199,490	191,273
Cash flow from investing activities:
Proceeds from sale of property, net	0	54,427	2,779
Acquisitions, net of cash acquired	(43,933)	(76,383)	(117,029)
Investments in unconsolidated entity	0	(4,144)	0
Additions to property and equipment	(773,812)	(361,160)	(484,303)
Net cash used in investing activities	(817,745)	(387,260)	(598,553)
Cash flow from financing activities:
Credit facility proceeds	827,582	399,028	483,000
Credit facility repayments	(759,000)	(334,000)	(362,000)
4.75% Senior Notes repayment	(400,000)	0	0
3.875% Senior Notes issuance	500,000	0	0
Term Loan D issuance	250,000	0	0
Payment of debt extinguishment costs	(14,252)	0	0
Payment of deferred financing costs	(9,559)	(5,130)	(3,964)
Payment of preferred stock dividends	(28,180)	(28,180)	(10,728)
Payment of common stock dividends	(111,311)	(94,085)	(82,579)
Distribution to noncontrolling interests	(12,330)	(11,533)	(10,759)
Proceeds from exercise of stock options	2,524	3,857	246
Payment of tax withholdings related to equity-based awards	(5,343)	(3,900)	(2,205)
Principal payments on finance lease obligations	(2,579)	(2,855)	(7,626)
Mortgage principal debt repayments	(1,736)	(65)	(66)
Preferred stock issuance proceeds, net of costs	0	0	407,477
Common stock issuance proceeds, net of costs	285,352	268,259	0
Net cash provided by financing activities	521,168	191,396	410,796
Effect of foreign currency exchange rates on cash and cash equivalents	3,984	268	0
Net change in cash and cash equivalents	7,122	3,894	3,516
Cash and cash equivalents, beginning of period	15,653	11,759	8,243
Cash and cash equivalents, end of period	22,775	15,653	11,759
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION
Cash paid for interest	54,596	56,023	51,380
Noncash investing and financing activities:
Accrued capital additions	121,194	92,206	76,890
Net increase (decrease) in other assets/liabilities related to change in fair value of derivative contracts	(27,113)	(28,952)	895
Equity received in unconsolidated entity in exchange for real estate assets	0	25,280	0
Increase in assets in exchange for finance lease obligation	0	45,024	0
Accrued equity issuance costs	0	30	115
Accrued preferred stock dividend	5,938	5,938	5,938
Accrued deferred financing costs	0	0	76
Acquisitions, net of cash acquired:
Land	0	1,743	0
Buildings, improvements and equipment	0	8,640	445
Construction in progress	43,933	61,514	114,283
Rents and other receivables, net	0	1,239	0
Acquired intangibles, net	0	2,628	2,301
Deferred costs	0	906	0
Prepaid expenses	0	359	0
Other assets	0	128	0
Accounts payable and accrued liabilities	0	(52)	0
Advance rents, security deposits and other liabilities	0	(722)	0
Total acquisitions, net of cash acquired	$ (43,933)	$ (76,383)	$ (117,029)

CONSOLIDATED STATEMENTS OF CA_2

CONSOLIDATED STATEMENTS OF CASH FLOW (Parenthetical)	Dec. 31, 2020	Oct. 07, 2020	Nov. 08, 2017
3.875% Senior Notes
Interest rate	3.875%	3.875%
Senior Notes | 4.75% Senior Notes
Interest rate	4.75%		4.75%

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and ContingenciesWe are subject to various routine legal proceedings and other matters in the ordinary course of business. We currently do not have any litigation that would have a material adverse impact on our financial statements. Additionally, we do not currently have any material contingencies related to the impact of COVID-19 reflected in our financial statements aside from certain increases to our general bad debt reserve provided for under ASC 450-20.

Description of Business

Description of Business	12 Months Ended
	Dec. 31, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of Business	Description of Business QTS Realty Trust, Inc. (“QTS”) through its controlling interest in QualityTech, LP (the “Operating Partnership” and collectively with QTS and its subsidiaries, the “Company,” “we,” “us,” or “our”) and the subsidiaries of the Operating Partnership, is engaged in the business of owning, acquiring, constructing, redeveloping and managing multi-tenant data centers. As of December 31, 2020 our portfolio consisted of 28 owned and leased properties, including a property owned by an unconsolidated entity, with data centers located throughout the United States, Canada and Europe. QTS elected to be taxed as a real estate investment trust (“REIT”) for U.S. federal income tax purposes, commencing with its taxable year ended December 31, 2013. As a REIT, QTS generally is not required to pay federal corporate income taxes on its taxable income to the extent it is currently distributed to its stockholders. The Operating Partnership is a Delaware limited partnership formed on August 5, 2009 and is QTS’ historical predecessor. As of December 31, 2020, QTS owned approximately 90.8% of the interests in the Operating Partnership. Substantially all of QTS’ assets are held by, and all of QTS’ operations are conducted through, the Operating Partnership. QTS’ interest in the Operating Partnership entitles QTS to share in cash distributions from, and in the profits and losses of, the Operating Partnership in proportion to QTS’ percentage ownership. As the sole general partner of the Operating Partnership, QTS generally has the exclusive power under the partnership agreement of the Operating Partnership to manage and conduct the Operating Partnership’s business and QTS’ board of directors manages the Operating Partnership and the Company’s business and affairs.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Basis of Presentation – The accompanying financial statements have been prepared by management in accordance with accounting principles generally accepted in the United States (“U.S. GAAP”). In the opinion of management, all adjustments (consisting of normal recurring adjustments) considered necessary for a fair presentation have been included. References to “QTS” mean QTS Realty Trust, Inc. and its controlled subsidiaries and references to the “Operating Partnership” mean QualityTech, LP and its controlled subsidiaries. The Operating Partnership meets the definition and criteria of a variable interest entity (“VIE”) in accordance with Accounting Standards Codification ("ASC") Topic 810 Consolidation , and the Company is the primary beneficiary of the VIE. As discussed below, the Company’s only material asset is its ownership interest in the Operating Partnership, and consequently, all of its assets and liabilities represent those assets and liabilities of the Operating Partnership. The Company’s debt is an obligation of the Operating Partnership where the creditors may have recourse, under certain circumstances, against the credit of the Company. QTS is the sole general partner of the Operating Partnership, and its only material asset consists of its ownership interest in the Operating Partnership. Management operates QTS and the Operating Partnership as one business. The management of QTS consists of the same employees as the management of the Operating Partnership. QTS does not conduct business itself, other than acting as the sole general partner of the Operating Partnership and issuing public equity from time to time. QTS has not issued or guaranteed any indebtedness. Except for net proceeds from public equity issuances by QTS, which are contributed to the Operating Partnership in exchange for units of limited partnership interest of the Operating Partnership, the Operating Partnership generates all remaining capital required by the business through its operations, the direct or indirect incurrence of indebtedness, and the issuance of partnership units. Therefore, as general partner with control of the Operating Partnership, QTS consolidates the Operating Partnership for financial reporting purposes. Obligations under the 3.875% Senior Notes due 2028 and the unsecured credit facility, both discussed in Note 8, are fully, unconditionally, and jointly and severally guaranteed by the Operating Partnership’s existing subsidiaries (other than certain foreign subsidiaries and receivables entities) and future subsidiaries that guarantee any indebtedness of QTS Realty Trust, Inc., the Operating Partnership, QTS Finance Corporation (the co-issuer of the 3.875% Senior Notes due 2028) or any subsidiary guarantor. The indenture governing the 3.875% Senior Notes due 2028 restricts the ability of the Operating Partnership to make distributions to QTS, subject to certain exceptions, including distributions required in order for QTS to maintain its status as a real estate investment trust under the Internal Revenue Code of 1986, as amended (the “Code”). The consolidated financial statements of QTS Realty Trust, Inc. include the accounts of QTS Realty Trust, Inc. and its majority owned controlled subsidiaries including the Operating Partnership as well as unconsolidated entities accounted for using equity method accounting. This includes the operating results of the Operating Partnership for all periods presented. Use of Estimates – The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, 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. Significant items subject to such estimates and assumptions include the useful lives of fixed assets, allowances for doubtful accounts and deferred tax assets and the valuation of derivatives, real estate assets, acquired intangible assets and certain accruals. The impacts of the COVID-19 pandemic increases uncertainty, which has reduced our ability to use past results to estimate future performance. Accordingly, our estimates and judgments may be subject to greater volatility than has been the case in the past. Principles of Consolidation – The consolidated financial statements of QTS Realty Trust, Inc. include the accounts of QTS Realty Trust, Inc. and its controlled subsidiaries. All significant intercompany accounts and transactions have been eliminated in the financial statements. We evaluate our investments in less than wholly owned entities to determine whether they should be recorded on a consolidated basis. The percentage of ownership interest in the entity, an evaluation of control and whether a VIE exists are all considered in our consolidation assessment. Investments in real estate entities which we have the ability to exercise significant influence, but do not have financial or operating control, are accounted for using the equity method of accounting. Accordingly, our share of the earnings or losses of these entities is included in consolidated net income (loss). Variable Interest Entities (VIEs) – We determine whether an entity is a VIE and, if so, whether it should be consolidated by utilizing judgments and estimates that are inherently subjective. The determination of whether an entity in which we hold a direct or indirect variable interest is a VIE is based on several factors, including whether the entity’s total equity investment at risk upon inception is sufficient to finance the entity’s activities without additional subordinated financial support. We make judgments regarding the sufficiency of the equity at risk based first on a qualitative analysis, and then a quantitative analysis, if necessary. We analyze any investments in VIEs to determine if we are the primary beneficiary. In evaluating whether we are the primary beneficiary, we evaluate our direct and indirect economic interests in the entity. Determining which reporting entity, if any, is the primary beneficiary of a VIE is primarily a qualitative approach focused on identifying which reporting entity has both (1) the power to direct the activities of a VIE that most significantly impact such entity’s economic performance and (2) the obligation to absorb losses or the right to receive benefits from such entity that could potentially be significant to such entity. Performance of that analysis requires the exercise of judgment. We consider a variety of factors in identifying the entity that holds the power to direct matters that most significantly impact the VIE’s economic performance including, but not limited to, the ability to direct financing, leasing, construction and other operating decisions and activities. In addition, we consider the rights of other investors to participate in those decisions, to replace the manager and to sell or liquidate the entity. We determine whether we are the primary beneficiary of a VIE at the time we become involved with a variable interest entity and reconsider that conclusion upon a reconsideration event. As of December 31, 2020, we had one unconsolidated entity that was considered a VIE for which we are not the primary beneficiary. Our maximum exposure to losses associated with this VIE is limited to our net investment, which was approximately $22.6 million as of December 31, 2020. Real Estate Assets – Real estate assets are reported at cost. All capital improvements for the income-producing properties that extend their useful lives are capitalized to individual property improvements and depreciated over their estimated useful lives. Depreciation for real estate assets is generally provided on a straight-line basis over 40 years from the date the property was placed in service. Property improvements are depreciated on a straight-line basis over the life of the respective improvement ranging from 20 to 40 years from the date the components were placed in service. Leasehold improvements are depreciated over the lesser of 20 years or through the end of the respective life of the lease. Repairs and maintenance costs are expensed as incurred. For the year ended December 31, 2020, depreciation expense related to real estate assets and non-real estate assets was $147.8 million and $13.4 million, respectively, for a total of $161.2 million. For the year ended December 31, 2019, depreciation expense related to real estate assets and non-real estate assets was $118.9 million and $11.9 million, respectively, for a total of $130.8 million. For the year ended December 31, 2018, depreciation expense related to real estate assets and non-real estate assets was $101.2 million and $12.3 million, respectively, for a total of $113.5 million. We capitalize certain real estate development costs, including internal costs incurred in connection with development. The capitalization of costs during the construction period (including interest and related loan fees, property taxes and other direct and indirect project costs) begins when development efforts commence and ends when the asset is ready for its intended use. The capitalization of internal costs increases construction in progress recognized during development of the related property and the cost of the real estate asset when placed into service and such costs are depreciated over its estimated useful life. Capitalization of such costs, excluding interest, aggregated to $18.4 million, $17.8 million and $17.4 million for the years ended December 31, 2020, 2019 and 2018 respectively. Interest is capitalized during the period of development by applying our weighted average effective borrowing rate to the actual development and other capitalized costs paid during the construction period. Interest is capitalized until the property is ready for its intended use. Interest costs capitalized totaled $30.2 million, $33.2 million and $26.8 million for the years ended December 31, 2020, 2019 and 2018, respectively. Acquisitions and Sales – Acquisitions of real estate and other entities are either accounted for as asset acquisitions or business combinations depending on facts and circumstances. When substantially all of the fair value of gross assets acquired is concentrated in a single identifiable asset or a group of similar identifiable assets, the transaction is accounted for as an asset acquisition. In an asset acquisition, the purchase price paid for assets acquired is allocated between identified tangible and intangible assets acquired based on relative fair value. Transaction costs associated with asset acquisitions are capitalized. When substantially all of the fair value of assets acquired is not concentrated in a group of similar identifiable assets, the set of assets will generally be considered a business. When accounting for business combinations, purchase accounting is applied to the assets and liabilities related to all real estate investments acquired in accordance with the accounting requirements of ASC Topic 805, Business Combinations , which requires the recording of net assets of acquired businesses at fair value. The fair value of the consideration transferred is assigned to the acquired tangible assets, consisting primarily of land, construction in progress, building and improvements, and identified intangible assets and liabilities, consisting of the value of above-market and below-market leases, value of in-place leases, value of customer relationships, and finance leases. The excess of the fair value of liabilities assumed, common stock issued and cash paid over the fair value of identifiable assets acquired is allocated to goodwill, which is not amortized. Transaction costs associated with business combinations are expensed as incurred. In developing estimates of fair value of acquired assets and assumed liabilities, management analyzes a variety of factors including market data, estimated future cash flows of the acquired operations, industry growth rates, current replacement cost for fixed assets and market rate assumptions for contractual obligations. Such a valuation requires management to make significant estimates and assumptions, particularly with respect to the intangible assets. Acquired in-place leases are amortized as amortization expense on a straight-line basis over the remaining life of the underlying leases. Acquired customer relationships are amortized as amortization expense on a straight-line basis over the expected life of the customer relationship. These amortization expenses are accounted for as real estate amortization expense. Above or below market leases are amortized on a straight-line basis over their expected lives and are recorded as a reduction to or increase in rental revenue when we are the lessor as well as a reduction to or increase in rent expense over the remaining lease terms when we are the lessee. We account for the sale of assets to non-customers under Financial Accounting Standards Board (“FASB”) ASU No. 2017-5, Other Income—Gains and Losses from the Derecognition of Nonfinancial Assets (Subtopic 610-20), which provides for recognition or derecognition based on transfer of ownership. During the year ended December 31, 2019, we sold our Manassas facility to an unconsolidated entity in exchange for cash consideration and noncash consideration in the form of an equity interest in the unconsolidated entity. After measuring the consideration received at fair value, we recognized a $13.4 million gain on sale of real estate, net of approximately $5.8 million of transaction costs, associated with our contribution of certain assets in our Manassas facility to the unconsolidated entity. Substantially all of the fair value of the assets contributed to the entity was concentrated in a group of similar identifiable assets and the sale of the assets were not to a customer, therefore the transaction was accounted for as an asset sale. The gain on sale of real estate is included within the “Gain on sale of real estate, net” line item of the consolidated statements of operations. In addition, during the year ended December 31, 2019, we recognized a $1.4 million gain on sale of certain land and improvements near our Atlanta (DC-1) (formerly known as Atlanta-Metro) facility which is included within the “Gain on sale of real estate, net” line item of the consolidated statements of operations. During the year ended December 31, 2018, we recognized a $7.0 million net loss on sale of equipment associated with our strategic growth plan which was included within the “Restructuring” line item of the consolidated statements of operations. Impairment of Long-Lived Assets, Intangible Assets and Goodwill – We review our long-lived assets, intangible assets and equity method investments for impairment when events or changes in circumstances indicate that the carrying amount of the assets may not be recoverable. Recoverability of assets to be held and used is measured by comparison of the carrying amount to the future net cash flows, undiscounted and without interest, expected to be generated by the asset group. If the net carrying value of the asset group exceeds the value of the undiscounted cash flows, the fair value of the asset group is assessed and may be considered impaired. An impairment loss is recognized based on the excess of the carrying amount of the impaired asset over its fair value. No impairment losses were recorded for the year ended December 31, 2020. For the year ended December 31, 2019, we recognized an $11.5 million impairment loss related to the write-down of certain data center assets and equipment in one of our Dulles, Virginia data centers. The Dulles campus has two data center buildings and we initiated a plan in the fourth quarter of 2019 to abandon one of the buildings and relocate customers from the smaller and older facility being abandoned to the newer facility in an effort to better optimize our operating cost structure. The impairment loss was included within the “Transaction, integration and impairment costs” line item of the consolidated statements of operations. For the year ended December 31, 2018, we recognized $8.8 million of impairment losses related to certain product-related assets, which was included in the “Restructuring” line item of the consolidated statements of operations. The fair value of goodwill is the consideration transferred in a business combination which is not allocable to identifiable intangible and tangible assets. Goodwill is subject to at least an annual assessment for impairment. In connection with the goodwill impairment evaluation that we performed as of October 1, 2020, we determined qualitatively that it is not more likely than not that the fair value of our one reporting unit was less than the carrying amount, thus we did not perform a quantitative analysis. As we continue to operate and assess our goodwill at the consolidated level for our single reporting unit and our market capitalization significantly exceeds our net asset value, further analysis was not deemed necessary as of December 31, 2020. Cash and Cash Equivalents – We consider all demand deposits and money market accounts purchased with a maturity date of three months or less at the date of purchase to be cash equivalents. Our account balances at one or more institutions periodically exceed the Federal Deposit Insurance Corporation (“FDIC”) insurance coverage and, as a result, there is concentration of credit risk related to amounts on deposit in excess of FDIC coverage. We mitigate this risk by depositing a majority of our funds with several major financial institutions. We also have not experienced any losses and do not believe that the risk is significant. Deferred Costs – Deferred costs, net, on our balance sheets include both deferred financing costs and deferred leasing costs. Deferred financing costs represent fees and other costs incurred in connection with obtaining debt and are amortized over the term of the loan and are included in interest expense. Debt issuance costs related to revolving debt arrangements are deferred and presented as assets on the balance sheet; however, all other debt issuance costs are recorded as a direct offset to the associated liability. Amortization of debt issuance costs, including those costs presented as offsets to the associated liability in the consolidated balance sheets, were $4.1 million, $3.9 million and $3.9 million for the years ended December 31, 2020, 2019 and 2018, respectively. During the year ended December 31, 2020, we wrote off unamortized financing costs of $3.7 million primarily in connection with the early extinguishment of the $400 million 4.750% senior notes due 2025. During the year ended December 31, 2019, we wrote off unamortized financing costs of $1.5 million in connection with the modification of our unsecured credit facility in October 2019 whereby we added a seven Deferred financing costs presented as assets on the balance sheets related to revolving debt arrangements, net of accumulated amortization are as follows: (dollars in thousands) December 31, December 31, Deferred financing costs $ 13,786 $ 13,776 Accumulated amortization (7,752) (5,743) Deferred financing costs, net $ 6,034 $ 8,033 Deferred financing costs presented as offsets to the associated liabilities on the balance sheets related to fixed debt arrangements, net of accumulated amortization, are as follows: (dollars in thousands) December 31, December 31, Deferred financing costs $ 19,327 $ 15,777 Accumulated amortization (4,765) (4,937) Deferred financing costs, net $ 14,562 $ 10,840 Initial direct costs, or deferred leasing costs, include commissions paid to third parties, including brokers, leasing and referral agents, and internal sales commissions paid to employees for successful execution of lease agreements and are accounted for pursuant to ASC Topic 842, Leases . These costs are incurred when we execute lease agreements and represent only incremental costs that would not have been incurred if the lease agreement had not been executed. To a lesser extent, we incur the same incremental costs to obtain managed services contracts with customers that are accounted for pursuant to ASC Topic 606, Revenue from Contracts with Customers . Because the framework of accounting for these costs and the underlying nature of the costs are the same for our revenue and lease contracts, the costs are presented on a combined basis within our financial statements and within the below table. Both revenue and leasing commissions are capitalized and generally amortized over the term of the related leases or the expected term of the contract using the straight-line method. If a customer lease terminates prior to the expiration of its initial term, any unamortized initial direct costs related to the lease are written off to amortization expense. Amortization of deferred leasing costs totaled $26.1 million, $24.2 million and $21.3 million for the years ended December 31, 2020, 2019 and 2018, respectively. Deferred leasing costs, net of accumulated amortization are as follows: (dollars in thousands) December 31, December 31, Deferred leasing costs $ 101,480 $ 77,178 Accumulated amortization (43,825) (32,848) Deferred leasing costs, net $ 57,655 $ 44,330 Revenue Recognition – We derive our revenues from leases with customers for data center space which include lease components and nonlease revenue components, such as power, tenant recoveries, and managed services. We adopted ASC Topic 842, Leases , the new accounting standard for leases, effective January 1, 2019 using the modified retrospective approach. We have elected the available practical expedient under ASC Topic 842, Leases , to combine our nonlease revenue components that have the same pattern of transfer as the related operating lease component into a single combined lease component. The single combined component is accounted for under ASC Topic 842 if the lease component is the predominant component and is accounted for under ASC Topic 606 if the nonlease components are the predominant components. In our contracts, the single combined component is accounted for under ASC Topic 842 as the lease component is the predominant component. A description of each of our disaggregated revenue streams is as follows: Rental Revenue Our leases with customers are classified as operating leases and rental revenue is recognized on a straight-line basis over the customer lease term. Occasionally, customer leases include options to extend or terminate the lease agreements. We do not include any of these extension or termination options in a customer’s lease term for lease classification purposes or recognizing rental revenue unless it is reasonably certain the customer will exercise these extension or termination options. Rental revenue also includes revenue from power delivery on fixed power arrangements, whereby customers are billed and pay a fixed monthly fee per committed available amount of connected power. These fixed power arrangements require us to provide a series of distinct services and to stand ready to deliver the power over the contracted term which is co-terminus with the lease. Customer fixed power arrangements have the same pattern of transfer over the lease term as the lease component and are therefore combined with the lease component to form a single lease component that is recognized over the term of the lease on a straight-line basis. In addition, rental revenue includes straight line rent. Straight line rent represents the difference in rents recognized during the period versus amounts contractually due pursuant to the underlying leases and is recorded as deferred rent receivable/payable in the consolidated balance sheets. For lease agreements that provide for scheduled rent increases, rental income is recognized on a straight-line basis over the non-cancellable term of the leases, which commences when control of the space has been provided to the customer. The amount of the straight-line rent receivable on the balance sheets included in rents and other receivables, net was $63.6 million and $38.7 million as of December 31, 2020 and December 31, 2019, respectively. Rental revenue also includes amortization of set-up fees which are amortized over the term of the respective lease as discussed below in the "Deferred Income" section. Variable Lease Revenue from Recoveries Certain customer leases contain provisions under which customers reimburse us for power and cooling-related charges as well as a portion of the property’s real estate taxes, insurance and other operating expenses. Recoveries of power and cooling-related expenses relate specifically to our variable power arrangements, whereby customers pay variable monthly fees for the specific amount of power utilized at the current utility rates. Our performance obligation is to stand ready to deliver power over the life of the customer contract up to a contracted power capacity. Customers have the flexibility to increase or decrease the amount of power consumed, and therefore sub-metered power revenue is constrained at contract inception. The reimbursements are included in revenue as recoveries from customers and are recognized each month as the uncertainty related to the consideration is resolved (i.e. we provide power to our customers) and customers utilize the power. Reimbursement of real estate taxes, insurance, common area maintenance, or other operating expenses are accounted for as variable payments under lease guidance pursuant to the practical expedient and are recognized as revenue in the period that the expenses are recognized. Variable lease revenue from recoveries discussed above, including power, common area maintenance or other operating costs, have the same pattern of transfer over the lease term as the lease component and are therefore combined with the lease component to form a single lease component. Variable lease revenue from recoveries is included within the “rental” line item on the statements of operations. Other Revenue Other revenue primarily consists of revenue from our managed service offerings as well as revenue earned from partner channel, management and development fees. We, through our TRS, may provide use of our managed services to our customers on an individual or combined basis. In our managed services offering the TRS’s performance obligation is to provide services (e.g. cloud hosting, data backup, data storage or data center personnel labor hours) to facilitate a fully integrated information technology (“IT”) outsourcing environment over a contracted term. Although underlying services may vary, over the contracted term monthly service offerings are substantially the same and we account for the services as a series of distinct services in accordance with ASC Topic 606. Service fee revenue is recognized as the revenue is earned, which generally coincides with the services being provided. As we have the right to consideration from customers in an amount that corresponds directly with the value to the customer of the TRS’s performance of providing continuous services, we recognize monthly revenue for the amount invoiced. With respect to the transaction price allocated to remaining performance obligations within our managed service contracts, we have elected to use the optional exemption provided by ASC Topic 606 whereby we are not required to estimate the total transaction price allocated to remaining performance obligations as we apply the “right-to-invoice” practical expedient. As described above, the nature of our performance obligation in these contracts is to provide monthly services that are substantially the same and accounted for as a series of distinct services. These contracts generally have a remaining term ranging from month-to-month to three years. Management fees and other revenues are generally received from our unconsolidated entity properties as well as third parties. Management fee revenue is earned based on a contractual percentage of unconsolidated entity property revenue. Development fee revenue is earned on a contractual percentage of hard costs to develop a property. We recognize revenue for these services provided when earned based on the performance criteria in ASC Topic 606, with such revenue recorded in “Other” revenue on the consolidated statements of operations. Allowance for Uncollectible Accounts Receivable – We record a provision for uncollectible accounts if a receivable balance relating to lease components from an individual contract is considered by management not to be probable of collection, and this provision is recorded as a reduction to leasing revenues. We also record a general provision of estimated uncollectible tenant receivables based on general probability of collection in accordance with ASC 450-20 Loss Contingencies . This provision is recorded as bad debt expense and recorded within the “Property Operating Costs” line item of the consolidated statements of operations. The aggregate allowance for doubtful accounts on the consolidated balance sheets was $5.4 million and $2.3 million as of December 31, 2020 and December 31, 2019, respectively. Advance Rents and Security Deposits – Advance rents, typically prepayment of the following month’s rent, consist of payments received from customers prior to the time they are earned and are recognized as revenue in subsequent periods when earned. Security deposits are collected from customers at the lease origination and are generally refunded to customers upon lease expiration. Deferred Income – Deferred income generally results from non-refundable charges paid by the customer at lease inception to prepare their space for occupancy. We record this initial payment, commonly referred to as set-up fees, as a deferred income liability which amortizes into rental revenue over the term of the related lease on a straight-line basis. Deferred income was $85.4 million, $39.2 million and $33.2 million as of December 31, 2020, 2019 and 2018, respectively. Additionally, $20.3 million, $15.2 million and $12.5 million of deferred income was amortized into revenue for the years ended December 31, 2020, 2019 and 2018, respectively. Foreign Currency - The financial position of foreign subsidiaries whose functional currency is not the U.S. dollar is translated at the exchange rates in effect at the end of the period, while revenues and expenses are translated at average exchange rates during the period. Gains or losses from translation of foreign operations where the local currency is the functional currency are included as components of other comprehensive income (loss). Prior to February 2020, gains or losses from foreign currency transactions were included in determining net income (loss). In February 2020, we entered into a net investment hedge which resulted in gains or losses subsequently being recognized in Other Comprehensive Income (Loss). Equity-based Compensation – Equity-based compensation costs are measured based upon their estimated fair value on the date of grant or modification and amortized ratably over their respective service periods. We have elected to account for forfeitures as they occur. Equity-based compensation expense was $27.0 million, $16.4 million, and $18.1 million for the years ended December 31, 2020, 2019 and 2018, respectively. Equity based compensation expense for the year ended December 31, 2020 includes $1.8 million of equity-based compensation expense associated with the revaluation and acceleration of equity awards related to an executive officer's retirement which is included within the "Transaction, integration, and impairment costs" line item of the consolidated statements of operations. Equity-based compensation expense for the year ended December 31, 2018 includes $3.1 million of equity-based compensation associated with the acceleration of equity awards related to certain employees impacted by the Company’s strategic growth plan which was included in the “Restructuring” expense line item on the consolidated statements of operations. Segment Information – We manage our business as one operating segment and thus one reportable segment consisting of a portfolio of investments in multiple data centers. Customer Concentrations – During the year ended December 31, 2020, one of our customers exceeded 10% of total revenues, representing approximately 11.8% of total revenues for the year ended December 31, 2020. As of

Acquisitions and Sales

Acquisitions and Sales	12 Months Ended
	Dec. 31, 2020
Business Combinations [Abstract]
Acquisitions and Sales	Acquisitions and Sales (All references to square footage, acres and megawatts are unaudited) Land Acquisitions During the year ended December 31, 2020, we completed multiple acquisitions of land totaling 126 acres for an aggregate purchase price of approximately $43.9 million to be used for future development. These acquisitions were accounted for as asset acquisitions and were included within the “Construction in Progress” line item of the consolidated balance sheets at the time of acquisition. During the year ended December 31, 2019, we completed multiple acquisitions of land totaling 107 acres for an aggregate purchase price of approximately $31.6 million to be used for future development. These acquisitions were accounted for as asset acquisitions and were included within the “Construction in Progress” line item of the consolidated balance sheets at the time of acquisition. Atlanta Land Improvement Sale In November 2019, we sold to a third-party certain land improvements which we had previously acquired as part of a larger acquisition of land to expand our Atlanta, Georgia campus. This sale of incidental real estate resulted in a gain of $1.4 million. Additionally, we entered into a ground lease with the Company as lessor and the acquirer of the building as lessee which has an initial term of 20 years. Netherlands Acquisition On April 23, 2019, we completed the acquisition of two data centers in the Netherlands (the “Netherlands facilities”) for approximately $44.5 million in cash consideration, including closing costs. At the time of acquisition, the two facilities, in Groningen and Eemshaven, had approximately 160,000 square feet of raised floor capacity and 30 megawatts of combined gross power available. This acquisition was funded with a draw on our unsecured revolving credit facility. The acquisition was accounted for as an asset acquisition. The purchase price allocation of the Netherlands facilities was a fair value estimate that utilized Level 2 and Level 3 inputs, including discounted future cash flows and observable market data on replacement costs, leasing rates, and discount rates that were used to measure the acquired assets and liabilities on a non-recurring basis. The following table summarizes the consideration for the Netherlands facilities and the allocation of the fair value of assets acquired and liabilities assumed at the acquisition date (in thousands): Purchase Price Allocation Weighted Avg Remaining Useful Life (in years) Land $ 1,743 N/A Buildings and improvements 8,640 24 Construction in progress 29,902 N/A Acquired intangibles (In-place lease & above market lease) 2,911 3 Deferred costs 906 3 Other assets 128 3 Net Working Capital 554 N/A Total identifiable assets acquired 44,784 Acquired below market lease 284 3 Total liabilities assumed 284 Net identifiable assets acquired $ 44,500

Acquired Intangible Assets and

Acquired Intangible Assets and Liabilities	12 Months Ended
	Dec. 31, 2020
Goodwill and Intangible Assets Disclosure [Abstract]
Acquired Intangibles Assets and Liabilities	Acquired Intangible Assets and Liabilities Summarized below are the carrying values for the major classes of intangible assets and liabilities (in thousands): December 31, 2020 December 31, 2019 Useful Lives Gross Accumulated Net Carrying Gross Accumulated Net Carrying Customer Relationships 12 years $ 95,705 $ (44,361) $ 51,344 $ 95,705 $ (36,411) $ 59,294 In-Place Leases 0.5 to 10 years 34,813 (26,812) 8,001 34,588 (22,522) 12,066 Solar Power Agreement (1) 17 years 13,747 (5,256) 8,491 13,747 (4,448) 9,299 Acquired Favorable Leases Acquired above market leases - as Lessor 0.5 to 8 years 5,070 (4,816) 254 5,035 (4,015) 1,020 Total Intangible Assets $ 149,335 $ (81,245) $ 68,090 $ 149,075 $ (67,396) $ 81,679 Solar Power Agreement (1) 17 years 13,747 (5,256) 8,491 13,747 (4,448) 9,299 Acquired Unfavorable Leases Acquired below market leases - as Lessor 2 to 4 years 1,117 (1,113) 4 1,092 (967) 125 Acquired above market leases - as Lessee 11 to 12 years 2,453 (1,199) 1,254 2,453 (983) 1,470 Total Intangible Liabilities (2) $ 17,317 $ (7,568) $ 9,749 $ 17,292 $ (6,398) $ 10,894 (1) Amortization related to the Solar Power Agreement asset and liability is recorded at the same rate and therefore has no net impact on the statements of operations. (2) Intangible liabilities are included within the “Advance rents, security deposits and other liabilities” line item of the consolidated balance sheets. Above or below market leases are amortized as a reduction to or increase in rental revenue in the case of the Company as lessor as well as a reduction to or increase in rent expense in the case of the Company as lessee over the remaining lease terms. The net effect of amortization of acquired above-market and below-market leases resulted in a net decrease in rental revenue of $0.4 million, $0.2 million, and $0.5 million for the years ended December 31, 2020, 2019 and 2018, respectively. The estimated amortization of acquired favorable and unfavorable leases for each of the five succeeding fiscal years ending December 31 is as follows (in thousands): Net Rental Revenue Net Rental Expense Decrease 2021 $ 164 $ (216) 2022 55 (216) 2023 25 (216) 2024 6 (216) 2025 — (216) Thereafter — (174) Total $ 250 $ (1,254) Net amortization of all other identified intangible assets and liabilities was $12.6 million, $13.2 million and $15.0 million for the years ended December 31, 2020, 2019 and 2018, respectively. The estimated net amortization of all other identified intangible assets and liabilities for each of the five succeeding fiscal years ending December 31 is as follows (in thousands): Year Ending December 31, 2021 $ 10,634 2022 10,088 2023 10,084 2024 8,967 2025 7,978 Thereafter 11,594 Total $ 59,345

Real Estate Assets and Construc

Real Estate Assets and Construction in Progress	12 Months Ended
	Dec. 31, 2020
Real Estate [Abstract]
Real Estate Assets and Construction in Progress	Real Estate Assets and Construction in Progress The following is a summary of our cost of owned or leased properties as of December 31, 2020 and 2019 (in thousands): As of December 31, 2020: Property Location Land Buildings, Improvements and Equipment Construction in Progress Total Cost Atlanta, Georgia Campus (1) $ 55,157 $ 700,142 $ 191,072 $ 946,371 Ashburn, Virginia Campus (2) 16,476 371,725 185,903 574,104 Irving, Texas 8,606 392,275 99,591 500,472 Chicago, Illinois 9,400 250,336 104,117 363,853 Richmond, Virginia 2,180 233,927 120,577 356,684 Suwanee, Georgia (Atlanta-Suwanee) 3,521 184,467 6,718 194,706 Piscataway, New Jersey 7,466 122,176 30,401 160,043 Fort Worth, Texas 9,079 124,054 1,064 134,197 Hillsboro, Oregon 18,414 34,594 78,390 131,398 Santa Clara, California (3) — 117,343 9,385 126,728 Leased Facilities (4) — 82,759 225 82,984 Eemshaven, Netherlands 5,366 21,712 47,531 74,609 Sacramento, California 1,481 66,300 12 67,793 Manassas, Virginia (5) — 25 67,073 67,098 Dulles, Virginia 3,154 54,323 4,148 61,625 Princeton, New Jersey 20,700 35,261 5 55,966 Phoenix, Arizona (5) — — 37,729 37,729 Groningen, Netherlands 1,896 11,206 3,730 16,832 Other (6) 2,213 36,636 41,094 79,943 $ 165,109 $ 2,839,261 $ 1,028,765 $ 4,033,135 (1) The “Atlanta, Georgia Campus” includes both the existing data center Atlanta (DC-1) as well as the recently developed data center Atlanta, GA (DC-2) on land adjacent to the existing Atlanta, GA (DC-1) facility. (2) The “Ashburn, Virginia Campus” includes both the existing data center Ashburn, VA (DC-1) as well as new property development associated with the construction of a second data center Ashburn, VA (DC-2). (3) Owned facility subject to long-term ground sublease. (4) Includes 7 facilities. All facilities are leased, including one subject to a finance lease. (5) Represent land purchases. Land acquisition costs, as well as subsequent development costs, are included within construction in progress until development on the land has ended and the asset is ready for its intended use. (6) Consists of Miami, FL; Lenexa, KS; Overland Park, KS and additional land. As of December 31, 2019: Property Location Land Buildings, Improvements and Equipment Construction in Progress Total Cost Atlanta, Georgia Campus (1) $ 44,588 $ 525,300 $ 128,930 $ 698,818 Irving, Texas 8,606 369,727 98,170 476,503 Ashburn, Virginia (2) 16,476 156,396 189,375 362,247 Richmond, Virginia 2,180 195,684 139,948 337,812 Chicago, Illinois 9,400 205,026 86,878 301,304 Suwanee, Georgia (Atlanta-Suwanee) 3,521 174,124 5,559 183,204 Piscataway, New Jersey 7,466 103,553 36,056 147,075 Santa Clara, California (3) — 114,499 1,238 115,737 Fort Worth, Texas 9,079 55,018 35,722 99,819 Leased Facilities (4) — 85,225 1,241 86,466 Sacramento, California 1,481 65,258 163 66,902 Hillsboro, Oregon (2) — — 63,573 63,573 Manassas, Virginia (2) — — 57,662 57,662 Princeton, New Jersey 20,700 35,192 39 55,931 Dulles, Virginia 3,154 48,651 4,688 56,493 Eemshaven, Netherlands — — 37,267 37,267 Phoenix, Arizona (2) — — 31,265 31,265 Groningen, Netherlands 1,741 9,085 3,028 13,854 Other (5) 2,213 36,163 120 38,496 $ 130,605 $ 2,178,901 $ 920,922 $ 3,230,428 (1) The “Atlanta, Georgia Campus” includes both the existing data center Atlanta (DC-1) as well as new property development associated with construction of a second data center Atlanta (DC-2) on land adjacent to the existing Atlanta (DC-1) facility. (2) Represent land purchases. Land acquisition costs, as well as subsequent development costs, are included within construction in progress until development on the land has ended and the asset is ready for its intended use. (3) Owned facility subject to long-term ground sublease. (4) Includes 7 facilities. All facilities are leased, including one subject to a finance lease. (5) Consists of Miami, FL; Lenexa, KS; and Overland Park, KS facilities.

Leases

Leases	12 Months Ended
	Dec. 31, 2020
Leases [Abstract]
Leases	Leases Leases as Lessee We determine if an arrangement is a lease at inception. If the contract is considered a lease, we evaluate leased property to determine whether the lease should be classified as a finance or operating lease in accordance with U.S. GAAP. We periodically enter into finance leases for certain data center facilities, equipment, and fiber optic transmission cabling. In addition, we lease certain real estate (primarily land or real estate space) under operating lease agreements with such assets included within the “Operating lease right of use assets, net” line item of the consolidated balance sheets and the associated lease liabilities included within the “Operating lease liabilities” line item on the consolidated balance sheets pursuant to ASC Topic 842. ROU assets represent our right to use an underlying asset for the lease term and lease liabilities represent our obligation to make lease payments arising from the lease. ROU assets and lease liabilities are recognized at the commencement date based on the present value of lease payments over the lease term. Variable lease payments consist of nonlease services related to the lease. Variable lease payments are excluded from the ROU assets and lease liabilities and are recognized in the period in which the obligation for those payments is incurred. As our leases as lessee typically do not provide an implicit rate, we use our incremental borrowing rate based on the information available at the commencement date in determining the present value of lease payments. We assess multiple variables when determining the incremental borrowing rate, such as lease term, payment terms, collateral, economic conditions, and creditworthiness. ROU assets also include any lease payments made and exclude lease incentives. Many of our lease agreements include options to extend the lease, which we do not include in our expected lease terms unless they are reasonably certain to be exercised. Rental expense for lease payments related to operating leases is recognized on a straight-line basis over the lease term. We use leasing as a source of financing for certain data center facilities and related equipment. We currently operate one data center facility, along with various equipment and fiber optic transmission cabling, that are subject to finance leases. The remaining terms of our finance leases range from less than one seventeen We currently lease six other facilities under operating lease agreements for various data centers, our corporate headquarters and additional office space. Our leases have remaining lease terms ranging from three six Components of lease expense were as follows (in thousands): Year Ended December 31, 2020 2019 Finance lease cost: Amortization of assets $ 4,150 $ 3,535 Interest on lease liabilities 1,915 1,693 Operating lease expense: Operating lease cost 9,012 9,102 Variable lease cost 1,072 1,109 Sublease income (193) (187) Total lease costs $ 15,956 $ 15,252 Supplemental balance sheet information related to leases was as follows (in thousands, except lease term and discount rate): As of December 31, 2020 2019 Operating leases: Operating lease right-of-use assets $ 51,342 $ 57,141 Operating lease liabilities 58,005 64,416 Finance leases: Property and equipment, at cost 49,554 50,437 Accumulated amortization (8,864) (4,830) Property and equipment, net $ 40,690 $ 45,607 Finance lease liabilities $ 41,718 $ 45,141 Weighted average remaining lease term (in years): Operating leases 13.4 13.7 Finance leases 10.3 11.4 Weighted average discount rate: Operating leases 5.2 % 5.1 % Finance leases 4.3 % 4.3 % Supplemental cash flow and other information related to leases was as follows (in thousands): Year Ended December 31, 2020 2019 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows for operating leases $ 12,048 $ 9,834 Operating cash flows for finance leases $ 1,914 $ 1,704 Financing cash flows for finance leases $ 2,579 $ 2,855 Maturities of lease liabilities, which exclude variable rent payments, are as follows (in thousands): December 31, 2020 Operating Leases Finance Leases 2021 $ 9,818 $ 4,446 2022 10,266 4,570 2023 10,393 4,707 2024 8,317 4,847 2025 8,036 4,992 Thereafter 40,872 28,902 Total Lease Payments $ 87,702 $ 52,464 Less: Imputed Interest 29,697 10,746 Total Lease Obligations $ 58,005 $ 41,718 Leases as lessor Our lease revenue contains both minimum lease payments as well as variable lease payments. See Note 2 - ‘Summary of Significant Accounting Policies’ for further details of our revenue streams and associated accounting treatment. The components of our lease revenue were as follows (in thousands): Year Ended December 31, 2020 2019 2018 Lease revenue: Minimum lease revenue $ 464,005 $ 409,157 $ 367,388 Variable lease revenue (primarily recoveries from customers) 55,853 55,966 46,232 Total lease revenue $ 519,858 $ 465,123 $ 413,620

Investments in Unconsolidated E

Investments in Unconsolidated Entity	12 Months Ended
	Dec. 31, 2020
Equity Method Investments and Joint Ventures [Abstract]
Investments in Unconsolidated Entity	Investments in Unconsolidated Entity During the three months ended March 31, 2019, we formed an unconsolidated entity with Alinda Capital Partners (“Alinda”), an infrastructure investment firm. We contributed a hyperscale data center under development in Manassas, Virginia to the entity. The facility, and the previously executed 10-year operating lease agreement with a global cloud-based software company, was contributed to the unconsolidated entity in exchange for cash and noncash consideration in the form of equity interest in the entity that was measured at fair value pursuant to Topic 820. The equity interest received and any amounts due from the unconsolidated entity are recorded within our consolidated balance sheets and totaled $22.6 million and $30.2 million as of December 31, 2020 and 2019, respectively. Alinda and us each own a 50% interest in the entity. As we are not the primary beneficiary of the arrangement but have the ability to exercise significant influence, we concluded that the investment should be accounted for as an unconsolidated entity using equity method investment accounting. As of December 31, 2020 and 2019, the total assets of the entity were $141.5 million and $127.8 million, respectively. As of December 31, 2020 and 2019, the total debt outstanding, net of deferred financing costs, was $90.1 million and $68.2 million, respectively. Under the equity method, our cost of investment is adjusted for additional contributions to and distributions from the unconsolidated entity, as well as our share of equity in the earnings and losses of the unconsolidated entity. Generally, distributions of cash flows from operations and capital events are made to members of the unconsolidated entity in accordance with each member’s ownership percentages and the terms of the agreement, but also provides us with rights to preferential cash distributions as certain phases are completed and leased to the underlying tenant. Our policy is to account for distributions from the unconsolidated entity on the basis of the nature of the activities that generated the distribution. Distributions from the operations of the unconsolidated entity are a return on our investment and we classify these distributions as operating cash flows. Any differences between the cost of our investment in an unconsolidated entity and its underlying equity as reflected in the unconsolidated entity’s financial statements generally result from costs of our investment that are not reflected on the unconsolidated entity’s financial statements. Under the unconsolidated entity agreement, we serve as the entity’s operating member, subject to authority and oversight of a board appointed by us and Alinda, and separately we serve as manager and developer of the facility in exchange for management and development fees. The entity agreement includes various transfer restrictions and rights of first offer that will allow us to repurchase Alinda’s interest should Alinda wish to exit in the future.

Debt

Debt	12 Months Ended
	Dec. 31, 2020
Debt Disclosure [Abstract]
Debt	Debt Below is a listing of our outstanding debt, including finance leases, as of December 31, 2020 and 2019 (in thousands): Weighted Average Effective Interest Rate at December 31, 2020 (1) Maturity Date December 31, 2020 December 31, 2019 Unsecured Credit Facility Revolving Credit Facility 1.41 % December 17, 2023 $ 392,337 $ 317,028 Term Loan A 3.26 % December 17, 2024 225,000 225,000 Term Loan B 3.30 % April 27, 2025 225,000 225,000 Term Loan C 3.46 % October 18, 2026 250,000 250,000 Term Loan D 1.45 % January 15, 2026 250,000 — 4.750% Senior Notes 4.75 % November 15, 2025 — 400,000 3.875% Senior Notes 3.88 % October 1, 2028 500,000 — Lenexa Mortgage 4.10 % May 1, 2022 — 1,736 Finance Leases 4.33 % 2021 - 2038 41,718 45,140 2.85 % 1,884,055 1,463,904 Less net debt issuance costs (14,562) (10,839) Total outstanding debt, net $ 1,869,493 $ 1,453,065 (1) The coupon interest rates associated with Term Loan A, Term Loan B, and Term Loan C incorporate the effects of our interest rate swaps in effect as of December 31, 2020. Credit Facilities, Senior Notes and Mortgage Notes Payable (a) Unsecured Credit Facility – In October 2019, we amended and restated our unsecured credit facility (the “unsecured credit facility”), which among other things increased the total potential borrowings, extended maturity dates, lowered interest rates, and provided for an additional term loan under the agreement. The unsecured credit facility includes a $225 million term loan which matures on December 17, 2024 (“Term Loan A”), a $225 million term loan which matures on April 27, 2025 (“Term Loan B”), an additional term loan of $250 million, which matures on October 18, 2026 (“Term Loan C”) and a $1.0 billion revolving credit facility which matures on December 17, 2023. The revolving portion of the unsecured credit facility has a one Under the unsecured credit facility, the capacity may be increased from the current capacity of $1.7 billion to $2.2 billion subject to certain conditions set forth in the credit agreement, including the consent of the administrative agent and obtaining necessary commitments. We are also required to pay a commitment fee to the lenders assessed on the unused portion of the unsecured revolving credit facility. At our election, we can prepay amounts outstanding under the unsecured credit facility, in whole or in part, without penalty or premium. Our ability to borrow under the unsecured credit facility is subject to ongoing compliance with a number of customary affirmative and negative covenants. As of December 31, 2020, we were in compliance with all of our covenants. As of December 31, 2020, we had outstanding $1.1 billion of indebtedness under the unsecured credit facility, consisting of $392.3 million of outstanding borrowings under the unsecured revolving credit facility and $700.0 million aggregate outstanding under Term Loans A, B and C, exclusive of net debt issuance costs of $7.1 million. In connection with the unsecured credit facility, as of December 31, 2020, we had letters of credit outstanding aggregating to $3.5 million. As of December 31, 2020, the weighted average interest rate for amounts outstanding under the unsecured credit facility, including the effects of interest rate swaps, was 2.65%. We have also entered into certain interest rate swap agreements. See Note 10 – ‘Derivative Instruments’ for additional details. ( b) Term Loan D – In October 2020, through our Operating Partnership, we entered into a $250 million term loan (“Term Loan D”) that matures on January 15, 2026. Consistent with our existing term loans, amounts outstanding under Term Loan D bear interest at a variable rate equal to, at our election, LIBOR or a base rate, plus a spread that will vary depending upon our leverage ratio. The spread ranges from 1.20% to 1.80% for LIBOR loans and 0.20% to 0.80% for base rate loans. In addition, Term Loan D contains a LIBOR floor of 0.25%. When combined with our current $1.7 billion unsecured credit facility, Term Loan D increases QTS' aggregate unsecured credit facility capacity to $1.95 billion. Term Loan D also provides for a $250 million accordion feature to increase borrowing capacity up to $500 million, subject to obtaining necessary commitments. Term Loan D contains various debt covenants with which we are subject to, and these debt covenants are substantially the same as the debt covenants associated with the unsecured credit facility. (c) 4.750% Senior Notes – In November 2017, the Operating Partnership and QTS Finance Corporation, a subsidiary of the Operating Partnership formed solely for the purpose of facilitating the offering of the previously outstanding 5.875% Senior Notes due 2022 (collectively, the “Issuers”), issued $400 million aggregate principal amount of 4.750% Senior Notes due 2025 (the “4.750% Senior Notes”) in a private offering. The 4.750% Senior Notes had an interest rate of 4.750% per annum, were issued at a price equal to 100% of their face value and were scheduled to mature on November 15, 2025. During the fourth quarter of 2020 we used availability on our unsecured revolving credit facility, which increased due to revolver repayments following the issuance of the 3.875% Senior Notes and closing of Term Loan D, to fund the redemption of, and satisfy and discharge the indenture pursuant to which the Issuers issued, all of their outstanding 4.750% Senior Notes. We incurred expenses in the fourth quarter of 2020 associated with the redemption of the 4.750% Senior Notes of $18.0 million, including early redemption fees of $14.3 million as well as noncash charges of $3.7 million related to the write off of existing deferred financing costs. (d) 3.875% Senior Notes – In October 2020, the Issuers issued $500 million aggregate principal amount of senior notes due October 1, 2028 (the “3.875% Senior Notes”) in a private offering. The 3.875% Senior Notes have an interest rate of 3.875% per annum and were issued at a price equal to 100% of their face value. The net proceeds from the offering were used to repay a portion of the amount outstanding under our unsecured revolving credit facility, and subsequently with availability under the unsecured revolving credit facility we funded the redemption of, and satisfied and discharged the indenture pursuant to which the Issuers issued, all of their outstanding 4.750% Senior Notes described above. As of December 31, 2020, the net debt issuance costs associated with the 3.875% Senior Notes were $7.5 million. The Issuers may redeem the 3.875% Senior Notes prior to maturity at their option at the prices set forth in the indenture dated as of October 7, 2020, among QTS, the Issuers, the guarantors named therein, and Deutsche Bank Trust Company Americas, as trustee (the “Indenture”). The Indenture also includes customary negative covenants, including limitations on asset sales, investments, distributions, incurrence of additional debt and affiliate transactions. The 3.875% Senior Notes are unconditionally guaranteed, jointly and severally, on a senior unsecured basis by all of the Operating Partnership’s existing subsidiaries (other than certain foreign subsidiaries and receivables entities) and future subsidiaries that guarantee any indebtedness of QTS Realty Trust, Inc., the Issuers or any other subsidiary guarantor, other than QTS Finance Corporation, the co-issuer of the 3.875% Senior Notes. QTS Realty Trust, Inc. does not guarantee the 3.875% Senior Notes and will not be required to guarantee the 3.875% Senior Notes except under certain circumstances. (e) Lenexa Mortgage – On March 8, 2017, we entered into a $1.9 million mortgage loan secured by our Lenexa facility. This mortgage had a fixed rate of 4.1%, with periodic principal payments due monthly and a balloon payment of $1.6 million scheduled for May 2022. In November of 2020 we paid off the outstanding loan balance of $1.7 million associated with the Lenexa mortgage. The annual remaining principal payment requirements of our debt securities as of December 31, 2020 per the contractual maturities, excluding extension options and excluding operating and finance leases, are as follows (in thousands): Year ending December 31, 2021 $ — 2022 — 2023 392,337 2024 225,000 2025 225,000 Thereafter 1,000,000 Total $ 1,842,337 As of December 31, 2020, we were in compliance with all of our covenants.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes We have elected for two of our existing subsidiaries to be taxed as TRS's pursuant to the REIT rules of the U.S. Internal Revenue Code. We also have subsidiaries subject to tax in non-US jurisdictions. For our TRS's, income taxes are accounted for under the asset and liability method in accordance with ASC 740. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases and operating loss and tax credit carryforwards. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. We consider whether it is more likely than not that some portion or all of the deferred tax assets will be realized. It is possible that some or all of our deferred tax assets could ultimately expire unused. The Company establishes valuation allowances against deferred tax assets when the ability to fully utilize these benefits is determined to be uncertain. The components of income tax provision from continuing operations are: For the Year Ended December 31, 2020 2019 2018 Current: U.S. federal $ — $ — $ (50) U.S. State 368 298 395 Outside United States 7 13 78 Total Current 375 311 423 Deferred: U.S. federal 71 (276) (3,727) U.S. State (66) (71) (64) Outside United States 58 (1) — Total Deferred 63 (348) (3,791) Total $ 438 $ (37) $ (3,368) Temporary differences and carry forwards which give rise to the deferred tax assets and liabilities are as follows: For the Year Ended December 31, 2020 2019 2018 Deferred tax assets Net operating loss carryforwards $ 22,950 $ 20,218 $ 17,610 Deferred revenue and setup charges 1,062 1,299 3,171 Operating lease liabilities 1,904 2,266 — Property and equipment — 512 — Leases 400 — 1 Credits 300 300 287 Bad debt reserve 191 18 409 Intangibles 1,038 804 — Interest expense carryforward IRC Sec. 163(j) 1,164 2,782 2,253 Equity compensation 1,654 1,119 952 Other 857 257 582 Gross deferred tax assets 31,520 29,575 25,265 Deferred tax liabilities Property and equipment (616) — (3,089) Goodwill (3,042) (2,494) (1,953) Intangibles — (591) (11,910) Operating lease right-of-use assets (1,056) (1,261) — Prepaid commissions (774) (1,007) (956) Other (218) (224) (93) Gross deferred tax liabilities (5,706) (5,577) (18,001) Net deferred tax asset 25,814 23,998 7,264 Valuation allowance (26,624) (24,747) (8,361) Net deferred tax liability $ (810) $ (749) $ (1,097) The taxable REIT subsidiaries currently have net operating loss carryforwards related to U.S. federal income taxes of $33.4 million that expire in 11-16 years and $42.3 million which have no expiration. The taxable REIT subsidiaries also have $86.0 million of net operating loss carryforwards relating to state income taxes that expire in 1-20 years. The Company’s interest expense carryforward of $4.5 million has no expiration. The effective tax rate is subject to change in the future due to various factors such as the operating performance of the taxable REIT subsidiaries, tax law changes and future business acquisitions. The differences between total income tax expense or benefit and the amount computed by applying the statutory income tax rate to income before provision for income taxes with respect to the TRS activity were as follows: For the Year Ended December 31, 2020 2019 2018 TRS Statutory rate applied to pre-tax loss $ (1,380) $ (12,991) $ (9,656) Permanent differences, net 248 16 97 State income tax, net of federal benefit (421) (2,868) (1,430) Foreign income tax 7 13 78 Federal and State rate change (1) (20) (146) Other 109 (110) 41 Valuation allowance increase 1,876 15,923 7,648 Total tax expense (benefit) $ 438 $ (37) $ (3,368) Effective tax rate (6.7) % 0.1 % 7.3 % On March 27, 2020, the United States enacted the Coronavirus Aid, Relief and Economic Security Act (CARES Act). The CARES Act is an emergency economic stimulus package that includes measures and tax provisions to strengthen the United States economy and fund a nationwide effort to curtail the effect of COVID-19. The CARES Act provides tax changes in response to the COVID-19 pandemic. Some of the provisions which impact our financial statements include the removal of certain limitations on utilization of net operating losses, increasing the ability to deduct interest expense, and amending certain provisions of the previously enacted Tax Cuts and Jobs Act. We have evaluated the impact of the CARES Act and determined that the impact of the CARES Act is immaterial to our consolidated financial statements. On December 27, 2020, the United States enacted the Consolidated Appropriations Act, 2021, a spending bill containing additional stimulus relief for the COVID-19 pandemic. Because the bill was enacted in close proximity to the end of the year, we continue to evaluate the Consolidated Appropriations Act, 2021 and have not yet identified any material impacts to the financial statements that may result from the bill. As of December 31, 2020, 2019 and 2018, we had no uncertain tax positions. If we accrue any interest or penalties on tax liabilities from significant uncertain tax positions, those items will be classified as interest expense and general and administrative expense, respectively, in the Statements of Operations and Statements of Comprehensive Income. For the years ended December 31, 2020, 2019, and 2018, we had accrued no such interest or penalties. We are currently not under examination by the Internal Revenue Service or any state or foreign jurisdictions. Tax years ending after December 31, 2016 remain subject to examination and assessment, state limitation periods included. Tax years ending December 31, 2009 through December 31, 2016 remain open solely for purposes of examination of our loss and credit carryforwards. We provide a valuation allowance against deferred tax assets if, based on management’s assessment of operating results and other available evidence, it is more likely than not that some or all of the deferred tax assets will not be realized. The evidence contemplated by management at December 31, 2020, 2019, and 2018 consists of current and prior operating results, available tax planning strategies, and the scheduled reversal of existing taxable temporary differences. Evidence from the scheduled reversal of taxable temporary differences relies on management judgments based on the accumulation of available evidence. Those judgments may be subject to change in the future as evidence available to management changes. Management’s assessment of the Company’s valuation allowance may further change based on our generation or ability to project of future operating income, and changes in tax policy or tax planning strategies. As of December 31, 2020, 2019, and 2018 valuation allowances of $26.6 million, $24.7 million and $8.4 million, respectively, were recognized against certain net federal and state deferred tax assets since it is more likely than not that the deferred tax assets will not be realized. The $1.9 million year-over-year change is primarily caused by the federal and state valuation allowances recorded due to ongoing operating losses of the taxable REIT subsidiaries. Additionally, some portion of the change to the valuation allowances relates to changes in the evidence available related to the scheduled reversal of

Derivative Instruments

Derivative Instruments	12 Months Ended
	Dec. 31, 2020
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Instruments	Derivative Instruments From time to time, we enter into derivative financial instruments to manage certain cash flow risks. Derivatives designated and qualifying as a hedge of the exposure to variability in the cash flows of a specific asset or liability that is attributable to a particular risk, such as interest rate risk, are considered cash flow hedges. Interest Rate Swaps Our objectives in using interest rate swaps are to reduce variability in interest expense and to manage exposure to adverse interest rate movements. To accomplish this objective, we primarily use interest rate swaps as part of our interest rate risk management strategy. Interest rate swaps designated as cash flow hedges involve the receipt of variable amounts from a counterparty in exchange for us making fixed-rate payments over the life of the agreements without exchange of the underlying notional amount. As of December 31, 2020, we had interest rate swap agreements in place with an aggregate notional amount of $700 million. The forward swap agreements effectively fix the interest rate on $700 million of term loan borrowings, $225 million of swaps allocated to Term Loan A, $225 million allocated to Term Loan B and $250 million allocated to Term Loan C, through the current maturity dates of the respective term loans. We reflect our interest rate swap agreements, which are designated as cash flow hedges, at fair value as either assets or liabilities on the consolidated balance sheets within the “Other assets, net” or “Derivative liabilities” line items, as applicable. As of December 31, 2020, and 2019 the fair value of interest rate swaps represented an aggregate liability of $49.8 million and $19.9 million, respectively. The forward interest rate swap agreements are derivatives that currently qualify for hedge accounting whereby we record the effective portion of changes in fair value of the interest rate swaps in accumulated other comprehensive income or loss on the consolidated balance sheets and statements of comprehensive income which is subsequently reclassified into earnings in the period that the hedged forecasted transaction affects earnings. Any ineffective portion of a derivative's change in fair value is immediately recognized within net income (loss). The amount reclassified from other comprehensive income to interest expense on the consolidated statements of operations was an increase to interest expense of $10.1 million, a reduction in interest expense of $1.0 million, and an increase to interest expense of $0.1 million for the years ended December 31, 2020, 2019,and 2018 respectively. There was no ineffectiveness recognized for the years ended December 31, 2020, 2019 and 2018. During the subsequent twelve months, beginning January 1, 2021, we estimate that $13.5 million will be reclassified from other comprehensive income as an increase to interest expense. Interest rate derivatives and their fair values as of December 31, 2020 and 2019 were as follows (in thousands): Notional Amount Fixed One Month LIBOR rate per annum Fair Value December 31, 2020 December 31, 2019 Effective Date Expiration Date December 31, 2020 December 31, 2019 $ 25,000 $ 25,000 1.989 % January 2, 2018 December 17, 2021 $ (447) $ (209) 100,000 100,000 1.989 % January 2, 2018 December 17, 2021 (1,788) (837) 75,000 75,000 1.989 % January 2, 2018 December 17, 2021 (1,342) (627) 50,000 50,000 2.033 % January 2, 2018 April 27, 2022 (1,248) (545) 100,000 100,000 2.029 % January 2, 2018 April 27, 2022 (2,490) (1,081) 50,000 50,000 2.033 % January 2, 2018 April 27, 2022 (1,248) (545) 100,000 100,000 2.617 % January 2, 2020 December 17, 2023 (7,191) (4,007) 100,000 100,000 2.621 % January 2, 2020 April 27, 2024 (8,000) (4,324) 70,000 — 0.968 % March 2, 2020 October 18, 2026 (2,174) — 30,000 — 0.973 % March 2, 2020 October 18, 2026 (938) — 200,000 200,000 2.636 % December 17, 2021 December 17, 2023 (9,648) (3,939) 200,000 200,000 2.642 % April 27, 2022 April 27, 2024 (9,500) (3,802) 125,000 — 1.014 % December 17, 2023 December 17, 2024 (704) — 100,000 — 1.035 % December 17, 2023 December 17, 2024 (584) — 75,000 — 1.110 % December 17, 2023 October 18, 2026 (866) — 100,000 — 1.088 % April 27, 2024 April 27, 2025 (540) — 125,000 — 1.082 % April 27, 2024 April 27, 2025 (666) — 75,000 — 0.977 % April 27, 2024 October 18, 2026 (422) — $ (49,796) $ (19,916) Power Purchase Agreements In March 2019, we entered into two 10 year agreements to purchase renewable energy equal to the expected electricity needs of our data centers in Chicago, Illinois and Piscataway, New Jersey. These arrangements currently qualify for hedge accounting whereby we record the changes in fair value of the instruments in “Accumulated other comprehensive income” or loss on the consolidated balance sheets and statements of comprehensive income which is subsequently reclassified into earnings in the period that the hedged forecasted transaction affects earnings. The amount reclassified from other comprehensive income to utility expense on the consolidated statements of operations was an increase to utilities expense of $1.2 million and an increase to utilities expense of $0.7 million for the years ended December 31, 2020 and 2019, respectively. There was no amount reclassified from other comprehensive income to utilities expense for the year ended December 31, 2018. We currently reflect these agreements, which are designated as cash flow hedges, at fair value as liabilities on the consolidated balance sheets within the “Derivative liabilities” line item. Power purchase agreement derivatives and their fair values as of December 31, 2020 and 2019 were as follows (in thousands): Fair Value Counterparty Facility Effective Date Expiration Date December 31, 2020 December 31, 2019 Calpine Energy Solutions, LLC Piscataway 3/8/2019 2/28/2029 $ (2,162) $ (2,919) Calpine Energy Solutions, LLC Chicago 3/8/2019 2/28/2029 (1,764) (3,774) $ (3,926) $ (6,693)

Partners' Capital, Equity and I

Partners' Capital, Equity and Incentive Compensation Plans	12 Months Ended
	Dec. 31, 2020
Equity [Abstract]
Partners' Capital, Equity and Incentive Compensation Plans	Partners’ Capital, Equity and Incentive Compensation PlansQualityTech, LP QTS has the full power and authority to do all the things necessary to conduct the business of the Operating Partnership. As of December 31, 2020, the Operating Partnership had four classes of limited partnership units outstanding: Series A Preferred Units, Series B Convertible Preferred Units, Class A units of limited partnership interest (“Class A units”) and Class O LTIP units of limited partnership units (“Class O units”). The Class A units currently outstanding are now redeemable on a one-for-one exchange rate at any time for cash or shares of Class A common stock of QTS. The Company may in its sole discretion elect to assume and satisfy the redemption amount with cash or its shares. Class O units were issued upon grants made under the QualityTech, LP 2010 Equity Incentive Plan (the “2010 Equity Incentive Plan”). Class O units are pari passu with Class A units. Each Class O unit is convertible into Class A units by the Operating Partnership at any time or by the holder at any time based on formulas contained in the partnership agreement. QTS Realty Trust, Inc. In connection with its IPO, QTS issued Class A common stock and Class B common stock. Class B common stock entitles the holder to 50 votes per share and was issued to enable our Chief Executive Officer to exchange 2% of his Operating Partnership units so he may have a vote proportionate to his economic interest in the Company. Also in connection with its IPO, QTS adopted the QTS Realty Trust, Inc. 2013 Equity Incentive Plan (the “2013 Equity Incentive Plan”), which authorized 1.75 million shares of Class A common stock to be issued under the 2013 Equity Incentive Plan, including options to purchase Class A common stock if exercised. On May 4, 2015, following approval by our stockholders at our 2015 Annual Meeting of Stockholders, the total number of shares available for issuance under the 2013 Equity Incentive Plan was increased by an additional 3.0 million shares. On May 9, 2019, following approval by our stockholders at our 2019 Annual Meeting of Stockholders, the total number of shares available for issuance under the 2013 Equity Incentive Plan was increased by an additional 1.1 million to 5.9 million. In March 2019, the Compensation Committee completed a redesign of the long-term incentive program for executive officers to include the following types of awards: a. Performance-Based FFO Unit Awards — performance-based restricted share unit awards, which may be earned based on Operating Funds From Operations (“OFFO”) per diluted share measured over a two-year performance period (performance-based FFO units or “FFO Units”), with two-thirds of the earned FFO Units vesting and settling in shares of Class A common stock on the date that performance is certified following the end of the performance period and the remaining one-third of the FFO Units vesting and settling at the end of three years from the award grant date. The number of shares of Class A common stock subject to the awards that can be earned ranges from 0% to 200% of the target award based on actual performance over the performance period, with the number of shares to be determined based on a linear interpolation basis between threshold and target and target and maximum performance. b. Performance-Based Relative TSR Unit Awards — performance-based restricted share unit awards, which may be earned based on total stockholder return (“TSR”) as compared to the MSCI U.S. REIT Index (the “Index”) over a three-year performance period (the performance-based relative TSR units or “TSR Units”). The number of shares of Class A common stock subject to the awards that can be earned ranges from 0% to 200% of the target award based on our TSR compared to the Index. In addition, award payouts will be determined on a linear interpolation basis between threshold and target and target and maximum performance; and will be capped at the target performance level if our TSR is negative. c. Restricted Stock Awards — the restricted stock awards vest as to one-third of the shares subject to awards on the first anniversary of the date of grant and as to 8.375% of the shares subject to the awards each quarter-end thereafter, subject to the named executive officer’s continued service as an employee as of each vesting date. The following is a summary of award activity under the 2010 Equity Incentive Plan and 2013 Equity Incentive Plan and related information for the years ended December 31, 2020, 2019 and 2018: 2010 Equity Incentive Plan 2013 Equity Incentive Plan Numbers of Class O Weighted average exercise Weighted average fair value Options Weighted average exercise Weighted average fair value Restricted Stock / Deferred Stock Weighted average fair value at grant date TSR Units Weighted average fair value at grant date FFO Units Weighted average fair value at grant date Outstanding at January 1, 2018 568,040 $ 23.52 $ 5.00 1,369,270 $ 38.18 $ 7.80 381,864 $ 46.37 — $ — — $ — Granted — — — 674,081 34.05 5.63 348,152 35.27 — — — — Exercised/Vested (1) (465,761) 23.40 4.76 (6,188) 21.50 3.68 (224,660) 46.23 — — — — Cancelled/Expired — — — — — — (85,047) 43.50 — — — — Outstanding at December 31, 2018 102,279 $ 24.05 $ 5.67 2,037,163 $ 36.86 $ 7.10 420,309 $ 37.83 — $ — — $ — Granted — — — 135,594 42.27 7.62 274,564 42.25 86,089 54.64 86,089 42.01 Exercised/Vested (1) (19,969) 20.25 4.42 (125,213) 30.80 6.21 (279,429) 39.20 — — — — Cancelled/Expired — — — (112,706) 45.86 9.43 (25,694) 42.17 (1,739) 54.64 (1,739) 42.01 Outstanding at December 31, 2019 82,310 $ 24.97 $ 5.97 1,934,838 $ 37.11 $ 7.05 389,750 $ 39.67 84,350 $ 54.64 84,350 $ 42.01 Granted — — — 99,872 56.84 9.35 302,591 57.47 84,202 79.18 84,202 56.84 Performance Adjustment (2) — — — — — — — — — — 59,844 42.01 Exercised/Vested (1) (6,875) 25.00 4.49 (98,303) 28.84 5.18 (264,466) 39.89 — — (96,129) 42.01 Cancelled/Expired — — — — — — (11,379) 49.38 — — — — Outstanding at December 31, 2020 75,435 $ 25.00 $ 6.11 1,936,407 $ 38.55 $ 7.26 416,496 $ 52.20 168,552 $ 66.90 132,267 $ 51.45 (1) Represents (i) Class O units which were converted to Class A units, (ii) options to purchase Class A common stock which were exercised, and (iii) the Class A common stock that has been released from restriction and which was not surrendered by the holder to satisfy their statutory minimum federal and state tax obligations associated with the vesting of restricted common stock, with respect to the applicable column. (2) Represents the remeasurement of FFO units issued during the year ended December 31, 2019 based on achievement of certain performance metrics over the performance period. The assumptions and fair values for restricted stock and options to purchase shares of Class A common stock granted for the years ended December 31, 2020, 2019 and 2018 are included in the following table on a per unit basis. Options to purchase shares of Class A common stock were valued using the Black-Scholes model and TSR Units were valued using a Monte-Carlo simulation that leveraged similar assumptions to those used to value the Class A common stock and FFO Units. 2020 2019 2018 Fair value of FFO units and restricted stock granted $56.84 - $65.96 $42.01 - $51.25 $34.03 - $54.01 Fair value of TSR units granted $79.18 $54.64 N/A Fair value of options granted $9.35 $7.56 - $8.28 $5.55 - $5.64 Expected term (years) 5.5 5.5 5.5 - 6.0 Expected volatility 27% 28% 28% Expected dividend yield 3.31 % 3.89% - 4.19% 4.82% Expected risk-free interest rates 0.61 % 2.33 % - 2.56 % 2.69 % - 2.73 % The following tables summarize information about awards outstanding as of December 31, 2020. Operating Partnership Awards Outstanding Exercise prices Awards outstanding Weight average remaining vesting period Class O Units $ 25.00 75,435 — Total Operating Partnership awards outstanding 75,435 QTS Realty Trust, Inc. Awards Outstanding Exercise prices Awards outstanding Weight average remaining vesting period Restricted stock $ — 416,496 1.0 TSR units — 168,552 0.9 FFO units — 132,267 0.7 Options to purchase Class A common stock $ 21.00 - $56.84 1,936,407 0.9 Total QTS Realty Trust, Inc. awards outstanding 2,653,722 Any awards outstanding as of the end of the period have been valued as of the grant date and generally vest ratably over a defined service period. As of December 31, 2020 all restricted Class A common stock, TSR units, and FFO units outstanding were unvested and approximately 0.1 million options to purchase Class A common stock were outstanding and unvested. As of December 31, 2020 we had $26.5 million of unrecognized equity-based compensation expense which will be recognized over a remaining weighted-average vesting period of approximately 0.9 years. The total intrinsic value of Class O units and options to purchase Class A common stock outstanding at December 31, 2020 was $48.3 million. Dividends and Distributions The following tables present quarterly cash dividends and distributions paid to our common and preferred stockholders for the years ended December 31, 2020 and 2019: Year Ended December 31, 2020 Record Date Payment Date Per Share Rate Aggregate Dividend/Distribution Amount (in millions) Common Stock September 18, 2020 October 6, 2020 $ 0.47 $ 32.0 June 19, 2020 July 7, 2020 0.47 31.5 March 20, 2020 April 7, 2020 0.47 31.5 December 20, 2019 January 7, 2020 0.44 28.6 $ 123.6 Series A Preferred Stock September 30, 2020 October 15, 2020 $ 0.45 $ 1.9 June 30, 2020 July 15, 2020 0.45 1.9 March 31, 2020 April 15, 2020 0.45 1.9 December 31, 2019 January 15, 2020 0.45 1.9 $ 7.6 Series B Preferred Stock September 30, 2020 October 15, 2020 $ 1.63 $ 5.1 June 30, 2020 July 15, 2020 1.63 5.1 March 31, 2020 April 15, 2020 1.63 5.1 December 31, 2019 January 15, 2020 1.63 5.1 $ 20.4 Year Ended December 31, 2019 Record Date Payment Date Per Share Rate Aggregate Dividend/Distribution Amount (in millions) Common Stock September 19, 2019 October 4, 2019 $ 0.44 $ 27.3 June 25, 2019 July 9, 2019 0.44 27.3 March 20, 2019 April 4, 2019 0.44 27.3 December 21, 2018 January 8, 2019 0.41 23.7 $ 105.6 Series A Preferred Stock September 30, 2019 October 15, 2019 $ 0.45 $ 1.9 June 30, 2019 July 15, 2019 0.45 1.9 March 31, 2019 April 15, 2019 0.45 1.9 December 31, 2018 January 15, 2019 0.45 1.9 $ 7.6 Series B Preferred Stock September 30, 2019 October 15, 2019 $ 1.63 $ 5.1 June 30, 2019 July 15, 2019 1.63 5.1 March 31, 2019 April 15, 2019 1.63 5.1 December 31, 2018 January 15, 2019 1.63 5.1 $ 20.4 Additionally, subsequent to December 31, 2020, we paid the following dividends: • On January 7, 2021, we paid our regular quarterly cash dividend of $0.47 per common share to stockholders of record as of the close of business on December 22, 2020. • On January 15, 2021, we paid a quarterly cash dividend of approximately $0.45 per share on our Series A Preferred Stock to holders of Series A Preferred Stock of record as of the close of business on December 31, 2020. • On January 15, 2021, we paid a quarterly cash dividend of approximately $1.63 per share on our Series B Preferred Stock to holders of Series B Preferred Stock of record as of the close of business on December 31, 2020. Equity Issuances Class A Common Stock In February 2019, we conducted an underwritten offering of 7,762,500 shares of our Class A common stock, $0.01 par value per share (the “Class A common stock”) consisting of 4,000,000 shares issued during the first quarter of 2019 and 3,762,500 shares which were issued on a forward basis. During the year ended December 31, 2019 we settled a portion of the 3,762,500 shares subject to the forward sales agreements, and during the year ended December 31, 2020 we settled the remaining shares subject to the forward sale agreements as shown in the table below. In June 2019, we established an “at-the-market” equity offering program (the “Prior ATM Program”) pursuant to which we could issue, from time to time, up to $400 million of our Class A common stock, $0.01 par value per share (the “Class A common stock”), which could include shares to be sold on a forward basis. The use of forward sales under the Prior ATM Program generally allowed us to lock in a price on the sale of shares of our Class A common stock when sold by the forward sellers, but defer receiving the net proceeds from such sales until the shares of our Class A common stock are issued at settlement on a later date. We have concluded that the forward sale agreements meet the derivative scope exception for certain contracts involving an entity’s own equity. The initial forward sale price is subject to daily adjustment based on a floating interest rate factor equal to the specified daily rate less a spread, and will decrease based on specified amounts related to dividends on shares of our common stock during the term of the applicable forward sale. Our earnings per share dilution resulting from the forward sale agreements, if any, is determined using the two-class method. In May 2020, we established a new “at-the-market” equity offering program (the “Current ATM Program”) pursuant to which we may issue, from time to time, up to $500 million of our Class A common stock, which may include shares to be sold on a forward basis. As under the Prior ATM Program, the use of forward sales under the Current ATM Program generally allows us to lock in a price on the sale of shares of our Class A common stock when sold by the forward sellers, but defer receiving the net proceeds from such sales until the shares of our Class A common stock are issued at settlement on a later date. We have concluded that the forward sale agreements meet the derivative scope exception for certain contracts involving an entity’s own equity. Our earnings per share dilution resulting from the forward sale agreements, if any, is determined using the two-class method. At any time during the term of any forward sale under the Prior ATM Program or the Current ATM Program we may settle the forward sale by physical delivery of shares of Class A common stock to the forward purchasers or, at our election, cash settle or net share settle. The initial forward sale price per share under each forward sale equals the product of (x) an amount equal to 100% minus the applicable forward selling commission and (y) the volume weighted average price per share at which the borrowed shares of our common stock were sold pursuant to the equity distribution agreement by the relevant forward seller during the applicable forward hedge selling period for such shares to hedge the relevant forward purchaser’s exposure under such forward sale. Thereafter, the forward sale price is subject to adjustment on a daily basis based on a floating interest rate factor equal to the specified daily rate less a spread, and is decreased based on specified amounts related to dividends on shares of our common stock during the term of the applicable forward sale. If the specified daily rate is less than the spread on any day, the interest rate factor will result in a daily reduction of the applicable forward sale price. During the year ended December 31, 2020, we received $286.3 million of net proceeds from the settlement of forward shares as noted in the table below. We expect to physically settle (by delivering shares of Class A common stock) the remaining forward sales under the Prior ATM Program and Current ATM Program prior to the first anniversary date of each respective transaction. In addition, during the year ended December 31, 2020, we utilized the forward provisions under the Prior ATM Program and the Current ATM Program to allow for the sale of additional shares of our common stock as noted in the table below. In June 2020, we conducted an underwritten offering of 4,400,000 shares of common stock offered on a forward basis at a price of $64.90 per share representing available net proceeds upon physical settlement of approximately $266.9 million as of December 31, 2020. We expect to physically settle the forward sale agreements (by the delivery of shares of common stock) and receive proceeds, subject to certain adjustments, from the sale of those shares of common stock by June 30, 2021, although we have the right to elect settlement prior to that time. We have concluded that the forward sale agreements meet the derivative scope exception for certain contracts involving an entity’s own equity. The initial forward sale price is subject to daily adjustment based on a floating interest rate factor equal to the specified daily rate less a spread, and will decrease based on specified amounts related to dividends on shares of our common stock during the term of the applicable forward sale. Our earnings per share dilution resulting from the forward sale agreements, if any, is determined using the two-class method. The following table represents a summary of our equity issuances of our Class A common stock during the year ended December 31, 2020 (in thousands): Offering Program Forward Net Proceeds Available/(Received) (1) Shares and net proceeds available as of December 31, 2019 3,795 $ 173,776 (2) February 2019 Offering - Settlement (931) (3) (35,841) June 2019 Prior ATM Program - Sales 4,550 243,577 June 2019 Prior ATM Program - Settlements (4,981) (3) (250,496) May 2020 Current ATM Program - Sales 3,128 189,640 June 2020 Offering - Sales 4,400 266,894 Shares and net proceeds available as of December 31, 2020 9,961 $ 587,550 (1) Net Proceeds Available remain subject to certain adjustments until settled. (2) Net Proceeds available reported in the Form 10-K for the period ended December 31, 2019 were $177.8 million. The $4 million decrease is primarily due to QTS’ declared dividends, which reduces cash expected to be received upon full physical settlement of the forward shares. (3) Represents the number of forward shares we elected to physically settle during the year ended December 31, 2020. Preferred Stock On March 15, 2018, QTS issued 4,280,000 shares of 7.125% Series A Cumulative Redeemable Perpetual Preferred Stock (“Series A Preferred Stock”) with a liquidation preference of $25.00 per share, which included 280,000 shares of the underwriters’ partial exercise of their option to purchase additional shares. In connection with the issuance of the Series A Preferred Stock, on March 15, 2018 the Operating Partnership issued to the Company 4,280,000 Series A Preferred Units, which have economic terms that are substantially similar to the Company’s Series A Preferred Stock. The Series A Preferred Units were issued in exchange for the Company’s contribution of the net offering proceeds of the offering of the Series A Preferred Stock to the Operating Partnership. Dividends on the Series A Preferred Stock are payable quarterly in arrears on or about the 15th day of each January, April, July and October. The Series A Preferred Stock does not have a stated maturity date and is not subject to any sinking fund or mandatory redemption provisions. Upon liquidation, dissolution or winding up, the Series A Preferred Stock will rank senior to common stock and pari passu with the Series B Preferred Stock with respect to the payment of distributions and other amounts. Except in instances relating to preservation of QTS’ qualification as a REIT or pursuant to the Company’s special optional redemption right, the Series A Preferred Stock is not redeemable prior to March 15, 2023. On and after March 15, 2023, the Company may, at its option, redeem the Series A Preferred Stock, in whole, at any time, or in part, from time to time, for cash at a redemption price of $25.00 per share, plus any accrued and unpaid dividends (whether or not declared) to, but not including, the date of redemption. Upon the occurrence of a change of control, the Company has a special optional redemption right that enables it to redeem the Series A Preferred Stock, in whole, at any time, or in part, from time to time, within 120 days after the first date on which a change of control has occurred resulting in neither QTS nor the surviving entity having a class of common shares listed on the NYSE, NYSE Amex, or NASDAQ or the acquisition of beneficial ownership of its stock entitling a person to exercise more than 50% of the total voting power of all our stock entitled to vote generally in election of directors. The special optional redemption price is $25.00 per share, plus any accrued and unpaid dividends (whether or not declared) to, but not including, the date of redemption. Upon the occurrence of a change of control, holders will have the right (unless the Company has elected to exercise its special optional redemption right to redeem their Series A Preferred Stock) to convert some or all of such holder’s Series A Preferred Stock into a number of shares of Class A common stock, par value $0.01 per share, equal to the lesser of: • the quotient obtained by dividing (i) the sum of the $25.00 liquidation preference plus the amount of any accrued and unpaid dividends (whether or not declared) to, but not including, the change of control conversion date (unless the change of control conversion date is after a record date for a Series A Preferred Stock dividend payment and prior to the corresponding Series A Preferred Stock dividend payment date, in which case no additional amount for such accrued and unpaid dividend will be included in this sum) by (ii) the Common Stock Price; and • 1.46929 (i.e., the Share Cap); subject, in each case, to certain adjustments and provisions for the receipt of alternative consideration of equivalent value as described in the prospectus supplement for the Series A Preferred Stock. On June 25, 2018, QTS issued 3,162,500 shares of 6.50% Series B Cumulative Convertible Perpetual Preferred Stock (“Series B Preferred Stock”) with a liquidation preference of $100.00 per share, which included 412,500 shares the underwriters purchased pursuant to the exercise of their overallotment option in full. In connection with the issuance of the Series B Preferred Stock, on June 25, 2018 the Operating Partnership issued to the Company 3,162,500 Series B Preferred Units, which have economic terms that are substantially similar to the Company’s Series B Preferred Stock. The Series B Preferred Units were issued in exchange for the Company’s contribution of the net offering proceeds of the offering of the Series B Preferred Stock to the Operating Partnership. Dividends on the Series B Preferred Stock are payable quarterly in arrears on or about the 15th day of each January, April, July and October. The Series B Preferred Stock is convertible by holders into shares of Class A common stock at any time at the then-prevailing conversion rate. The conversion rate as of December 31, 2020 is 2.1404 shares of the Company’s Class A common stock per share of Series B Preferred Stock. The Series B Preferred Stock does not have a stated maturity date. Upon liquidation, dissolution or winding up, the Series B Preferred Stock will rank senior to common stock and pari passu with the Series A Preferred Stock with respect to the payment of distributions and other amounts. The Series B Preferred Stock is not redeemable by the Company. At any time on or after July 20, 2023, the Company may at its option cause all (but not less than all) outstanding shares of the Series B Preferred Stock to be automatically converted into the Company’s Class A common stock at the then-prevailing conversion rate if the closing sale price of the Company’s Class A common stock is equal to or exceeds 150% of the then-prevailing conversion price for at least 20 trading days in a period of 30 consecutive trading days, including the last trading day of such 30-day period, ending on the trading day prior to the issuance of a press release announcing the mandatory conversion. If a holder converts its shares of Series B Preferred Stock at any time beginning at the opening of business on the trading day immediately following the effective date of a fundamental change (as described in the prospectus supplement) and ending at the close of business on the 30th trading day immediately following such effective date, the holder will automatically receive a number of shares of the Company’s Class A common stock equal to the greater of: • the sum of (i) a number of shares of the Company’s Class A common stock, as may be adjusted, as described in the Articles Supplementary for the 6.50% Series B Cumulative Convertible Perpetual Preferred Stock filed with the State Department of Assessments and Taxation of Maryland on June 22, 2018 (the “Articles Supplementary”) and (ii) the make-whole premium described in the Articles Supplementary; and • a number of shares of the Company's Class A common stock equal to the lesser of (i) the liquidation preference divided by the average of the daily volume weighted average prices of the Company's Class A common stock for ten days preceding the effective date of a fundamental change and (ii) 5.1020 (subject to adjustment). QTS Realty Trust, Inc. Employee Stock Purchase Plan In June 2015, we established the QTS Realty Trust, Inc. Employee Stock Purchase Plan (the “2015 Plan”) to give eligible employees the opportunity to purchase, through payroll deductions, shares of our Class A common stock in the open market by an independent broker with the Company paying brokerage commissions and fees associated with such share purchases. The 2015 Plan became effective July 1, 2015. We reserved 250,000 shares of our Class A common stock for purchase under the 2015 Plan, which were registered pursuant to a registration statement on Form S-8 filed on June 17, 2015. On May 4, 2017, our stockholders approved the 2017 Amended and Restated QTS Realty Trust, Inc. Employee Stock Purchase Plan (the “2017 Plan”). The 2017 Plan became effective July 1, 2017 and is administered by the compensation committee (the “Compensation Committee”) of the board of directors (or by a committee of one or more persons appointed by it or the board of directors). The 2017 Plan permits participants to purchase our Class A common stock at a discount of up to 10% (as determined by the Compensation Committee). Employees of our Company and our majority-owned subsidiaries who have been employed for at least thirty days and who perform at least thirty hours of service per week for our Company are eligible to participate in the 2017 Plan, excluding any employee who, at any time during which the payroll deductions are made on behalf of the participating employees to purchase stock, owns shares representing five percent or more of the total combined voting power or value of all classes of shares of our Company, or who is a Section 16 officer. Under the 2017 Plan, there are four purchase periods per year, and participants may deduct a minimum of $20 per paycheck and a maximum of $1,000 per paycheck towards the purchase of shares. Shares purchased under the 2017 Plan are subject to a one Effective February 1, 2020, the 2017 Plan was further amended and restated to, among other things, provide that employees of our Company and our majority-owned subsidiaries who have been employed for at least thirty days and who are regular full-time employees are eligible to participate in the 2017 Plan, excluding temporary or part-time employees and interns, any employee who, at any time during which the payroll deductions are made on behalf of the participating employees to purchase stock, owns shares representing five percent or more of the total combined voting power or value of all classes of shares of our Company, or any employee who is a Section 16 officer. In addition, such amendment and restatement provides that the $1,000 per paycheck limit on each participant’s purchase of shares assumes 24 pay periods per year and will be adjusted to the extent a participant is paid on a more frequent or infrequent basis.

Related Party Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2020
Related Party Transactions [Abstract]
Related Party Transactions	Related Party Transactions As described further in Note 7 ' Investments in Unconsolidated Entity' , during the three months ended March 31, 2019, we formed an unconsolidated entity with Alinda, an infrastructure investment firm. We contributed a hyperscale data center under development in Manassas, Virginia to the entity. The facility, and the previously executed operating lease to a global cloud-based software company pursuant to a 10-year lease agreement, was contributed in exchange for cash and noncash consideration in the form of equity interest in the entity that was measured at fair value pursuant to ASC Topic 820. Alinda and us each own a 50% interest in the entity. Under the unconsolidated entity operating agreement, we serve as the entity’s operating member, subject to authority and oversight of a board appointed by us and Alinda, and separately we serve as manager and developer of the facility in exchange for management and development fees. During the years ended December 31, 2020 and 2019, we received $0.9 million and $0.6 million in development fees from the unconsolidated entity, respectively, as well as $0.8 million and $0.6 million in management fees from the unconsolidated entity, respectively. In addition, we periodically execute transactions with entities affiliated with our Chairman and Chief Executive Officer. Such transactions include automobile, furniture and equipment purchases as well as building operating lease payments and receipts, and reimbursement for the use of a private aircraft service by our officers and directors. The transactions which occurred during the years ended December 31, 2020, 2019 and 2018 are outlined below (in thousands): For the Year Ended December 31, 2020 2019 2018 Tax, utility, insurance and other reimbursement $ 694 $ 967 $ 724 Rent expense 1,027 1,014 1,014 Capital assets acquired — 704 464 Total $ 1,721 $ 2,685 $ 2,202

Employee Benefit Plan

Employee Benefit Plan	12 Months Ended
	Dec. 31, 2020
Postemployment Benefits [Abstract]
Employee Benefit Plan	Employee Benefit Plan We sponsor a defined contribution 401(k) retirement plan covering all eligible employees. Qualified employees may elect to contribute to the 401(k) Plan on a pre-tax or post-tax basis. The maximum amount of employee contribution is subject only to statutory limitations. Starting on January 1, 2015, the Company matched 50% of the first 6% of contributions made by employees. Since January 1, 2016, we have matched 100% of the first 1% of contributions and 50% of the next 5% of contributions made by employees. We contributed $2.6 million, $2.5 million and $2.5 million to the 401(k) Plan for the years ended December 31, 2020, 2019 and 2018, respectively.

Noncontrolling Interest

Noncontrolling Interest	12 Months Ended
	Dec. 31, 2020
Noncontrolling Interest [Abstract]
Noncontrolling Interest	Noncontrolling Interest Concurrently with the completion of the IPO, we consummated a series of transactions pursuant to which QTS became the sole general partner and majority owner of QualityTech, LP, which then became its operating partnership. The previous owners of QualityTech, LP retained 21.2% ownership of the Operating Partnership as of the date of the IPO. Commencing at any time beginning November 1, 2014, at the election of the holders of the noncontrolling interest, the currently outstanding Class A units of the Operating Partnership are redeemable for cash or, at the election of the Company, Class A common stock of the Company on a one-for-one basis. As of December 31, 2020, the noncontrolling ownership interest percentage of QualityTech, LP was 9.2%.

Earnings per share

Earnings per share	12 Months Ended
	Dec. 31, 2020
Earnings Per Share [Abstract]
Earnings per Share	Earnings per shareBasic income (loss) per share is calculated by dividing the net income (loss) attributable to common shares by the weighted average number of common shares outstanding during the period. Diluted income (loss) per share adjusts basic income per share for the effects of potentially dilutive common shares. Unvested restricted stock awards and our forward sale contracts described in Note 12 contain non-forfeitable rights to dividends and thus are participating securities and are included in the computation of basic earnings per share pursuant to the two-class method for all periods presented. The two-class method is an earnings allocation formula that treats a participating security as having rights to undistributed earnings that would otherwise have been available to common stockholders. Accordingly, service-based restricted stock awards and the forward sale contracts were included in the calculation of basic earnings per share using the two-class method for all periods presented to the extent outstanding during the period. The computation of basic and diluted net income (loss) per share is as follows (in thousands, except per share data): Year Ended December 31, 2020 2019 2018 Numerator: Net income (loss) $ 14,576 $ 31,665 $ (7,175) (Income) loss attributable to noncontrolling interests 1,330 (374) 2,715 Preferred stock dividends (28,180) (28,180) (16,666) Earnings attributable to participating securities (16,360) (7,828) (947) Net loss available to common stockholders after allocation to participating securities $ (28,634) $ (4,717) $ (22,073) Denominator: Weighted average shares outstanding - basic 60,717 54,837 50,433 Effect of Class O units, TSR units, FFO units and options to purchase Class A common stock on an "as if" converted basis — — — Weighted average shares outstanding - diluted 60,717 54,837 50,433 Basic net loss per share * $ (0.47) $ (0.09) $ (0.44) Diluted net loss per share * $ (0.47) $ (0.09) $ (0.44) * Note: The calculations of basic and diluted net income (loss) per share above do not include the following number of Class A partnership units, Class O units, TSR units, FFO units and options to purchase common stock on an "as if" converted basis, and the effects of Series B Convertible preferred stock on an “as if” converted basis as their respective inclusions would have been antidilutive: Year Ended December 31, 2020 2019 2018 Class A Partnership units 6,648 6,671 6,653 Class O units, TSR units, FFO units and options to purchase common stock on an "as if" converted basis 1,118 518 350 Series B Convertible preferred stock on an "as if" converted basis 6,778 6,729 3,484

Contracts with Customers

Contracts with Customers	12 Months Ended
	Dec. 31, 2020
Revenue from Contract with Customer [Abstract]
Contracts with Customers	Contracts with Customers Future minimum payments to be received under non-cancelable customer contracts including both lease rental revenue components and non-lease revenue components that are accounted for as a combined lease component in accordance with ASC Topic 842 which is discussed in Note 2 above (inclusive of payments for contracts which have not yet commenced, and exclusive of variable lease revenue such as recoveries of operating costs from customers) are as follows for the years ending December 31 (in thousands): Year Ended December 31, 2021 $ 435,906 2022 359,860 2023 263,413 2024 214,215 2025 165,002 Thereafter 493,839 Total $ 1,932,235

Fair Value of Financial Instrum

Fair Value of Financial Instruments	12 Months Ended
	Dec. 31, 2020
Fair Value Disclosures [Abstract]
Fair Value of Financial Instruments	Fair Value of Financial Instruments ASC Topic 825, Financial Instruments , requires disclosure of fair value information about financial instruments, whether or not recognized in the consolidated balance sheets, for which it is practicable to estimate that value. In cases where quoted market prices are not available, fair values are based upon the application of discount rates to estimated future cash flows based upon market yields or by using other valuation methodologies. Considerable judgment is necessary to interpret market data and develop estimated fair value. Accordingly, fair values are not necessarily indicative of the amounts we could realize on disposition of the financial instruments. The use of different market assumptions and/or estimation methodologies may have a material effect on estimated fair value amounts. Short-term instruments: The carrying amounts of cash and cash equivalents and restricted cash approximate fair value. Derivative Contracts: Interest rate swaps Currently, we use interest rate swaps to manage our interest rate risk. The valuation of these instruments is determined using widely accepted valuation techniques including discounted cash flow analysis on the expected cash flows of each derivative. This analysis reflects the contractual terms of the derivatives, including the period to maturity, and uses observable market-based inputs, including interest rate curves. The fair values of interest rate swaps are determined using the market standard methodology of netting the discounted future fixed cash receipts (or payments) and the discounted expected variable cash payments (or receipts). The variable cash payments (or receipts) are based on an expectation of future interest rates (forward curves) derived from observable market interest rate curves. To comply with the provisions of fair value accounting guidance, we incorporate credit valuation adjustments to appropriately reflect both our own nonperformance risk and the respective counterparty’s nonperformance risk in the fair value measurements. In adjusting the fair value of our derivative contracts for the effect of nonperformance risk, we have considered the impact of netting and any applicable credit enhancements, such as collateral postings, thresholds, mutual puts, and guarantees. Although we have determined that the majority of the inputs used to value our derivatives fall within Level 2 of the fair value hierarchy, the credit valuation adjustments associated with our derivatives utilize Level 3 inputs, such as estimates of current credit spreads to evaluate the likelihood of default by us and our counterparties. However, as of December 31, 2020, we assessed the significance of the impact of the credit valuation adjustments on the overall valuation of our derivative positions and determined that the credit valuation adjustments are not significant to the overall valuation of our derivatives. As a result, we have determined that our derivative valuations in their entirety are classified in Level 2 of the fair value hierarchy. We do not have any fair value measurements on a recurring basis using significant unobservable inputs (Level 3) as of December 31, 2020 or December 31, 2019. Power Purchase Agreements In March 2019, we began using energy hedges to manage risk related to energy prices. The inputs used to value the derivatives primarily fall within Level 2 of the fair value hierarchy, and valuation of these instruments is determined using widely accepted valuation techniques including discounted cash flow analysis on the expected cash flows of each contract. This analysis reflects the contractual terms of the derivatives, including the period to maturity, and uses observable market-based inputs, including futures curves. The fair values of the energy hedges are determined using the market standard methodology of netting the discounted future fixed cash receipts (or payments) and the discounted expected variable cash payments (or receipts). The variable cash payments (or receipts) are based on an expectation of future energy rates (forward curves) derived from observable market futures curves. To comply with the provisions of fair value accounting guidance, we incorporate credit valuation adjustments to appropriately reflect both our own nonperformance risk and the respective counterparty’s nonperformance risk in the fair value measurements. In adjusting the fair value of our derivative contracts for the effect of nonperformance risk, we have considered the impact of netting and any applicable credit enhancements, such as collateral postings, thresholds, mutual puts, and guarantees. Sale of assets: During the year ended December 31, 2019, we recognized a gain on the sale of real estate assets that is discussed in detail in Note 7. In order to determine fair value of the noncash equity consideration received for the sale of the assets, we utilized estimation models to derive the fair value of the equity interest received in the transaction. These estimation models consisted of generally acceptable real estate valuation models as well as discounted cash flow analysis that included Level 3 inputs including market rents, discount rates, expected occupancy and estimates of additional capital expenditures, and capitalization rates derived from market data. Unsecured Credit facility, Term Loan D and 3.875% Senior Notes: As market interest rates have fluctuated compared to contracted interest rates, the fair value of our unsecured credit facility approximated the carrying value of the credit facility less the fair value of the interest rate swap liability. Our Term Loan D did not have interest rates which were materially different than current market conditions and therefore, the fair value approximated the carrying value. The fair value of our 3.875% Senior Notes was estimated using Level 2 “significant other observable inputs,” primarily based on quoted market prices for the same or similar issuances. At December 31, 2020, the fair value of the 3.875% Senior Notes was approximately $508.8 million. Other debt instruments: The fair value of our other debt instruments (including finance leases and mortgage notes payable) were estimated in the same manner as the unsecured credit facility above. Similarly, each of these instruments did not have interest rates which were materially different than current market conditions and therefore, the fair value of each instrument approximated the respective carrying values.

Quarterly Financial Information

Quarterly Financial Information	12 Months Ended
	Dec. 31, 2020
Quarterly Financial Information Disclosure [Abstract]
Quarterly Financial Information	Quarterly Financial Information (unaudited) The tables below reflect the selected quarterly information for the years ended December 31, 2020 and 2019 (in thousands except share data): Three Months Ended December 31, September 30, June 30, March 31, 2020 Revenues $ 143,897 $ 137,538 $ 131,640 $ 126,292 Operating income 17,151 15,016 17,859 15,631 Net income (loss) (10,660) 6,907 10,209 8,120 Net income (loss) attributable to QTS Realty Trust, Inc. (8,922) 6,925 9,892 8,010 Net income (loss) attributable to common stockholders (15,967) (120) 2,847 965 Net loss per share attributable to common shares - basic (0.33) (0.07) (0.05) (0.01) Net loss per share attributable to common shares - diluted (0.33) (0.07) (0.05) (0.01) 2019 Revenues $ 123,707 $ 125,255 $ 119,167 $ 112,689 Operating income 4,218 13,606 14,598 28,734 Net income (loss) (3,606) 6,588 7,535 21,148 Net income (loss) attributable to QTS Realty Trust, Inc. (2,511) 6,637 7,483 19,558 Net income (loss) attributable to common stockholders (9,556) (408) 438 12,513 Net income (loss) per share attributable to common shares - basic (0.20) (0.05) (0.03) 0.20 Net income (loss) per share attributable to common shares - diluted (0.20) (0.05) (0.03) 0.20

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2020
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events In January 2021, we paid our regular quarterly cash dividends on our common stock, Series A Preferred Stock and Series B Preferred Stock. See the ‘Dividends and Distributions’ section of Note 12 for additional details. Subsequent to December 31, 2020, the Company authorized the following dividends: • On February 3, 2021, the Company announced that its board of directors authorized payment of a regular quarterly cash dividend of $0.50 per common share, payable on April 6, 2021, to stockholders of record as of the close of business on March 19, 2021. • On February 3, 2021, the Company announced that its board of directors authorized payment of a regular quarterly cash dividend of approximately $0.45 per share on its Series A Preferred Stock, payable on April 15, 2021, to holders of Series A Preferred Stock of record as of the close of business on March 31, 2021.

Schedule II - Valuation and Qua

Schedule II - Valuation and Qualifying Accounts	12 Months Ended
	Dec. 31, 2020
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
Schedule II - Valuation and Qualifying Accounts	QTS REALTY TRUST, INC. SCHEDULE II – VALUATION AND QUALIFYING ACCOUNTS December 31, 2020 Year Ended December 31, Balance at Charge to Additions/ Balance at Allowance for uncollectible receivables 2020 $ 2,279 $ 5,051 $ (1,891) $ 5,439 2019 3,764 2,859 (4,344) 2,279 2018 11,453 (2,275) (5,414) 3,764 Valuation allowance for deferred tax assets 2020 $ 24,747 $ 1,877 $ — $ 26,624 2019 8,361 16,386 — 24,747 2018 713 7,648 — 8,361

Schedule III - Real Estate Inve

Schedule III - Real Estate Investments	12 Months Ended
	Dec. 31, 2020
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation Disclosure [Abstract]
Schedule III - Real Estate Investments	QTS REALTY TRUST, INC. SCHEDULE III – REAL ESTATE INVESTMENTS December 31, 2020 Initial Costs Costs Capitalized Subsequent to Acquisition Gross Carrying Amount As of 12/31/2020 (dollars in thousands) Land Buildings and Construction Land Buildings and Construction Land Buildings and Construction Accumulated Year of Property Location Owned Properties Ashburn, Virginia (DC-1) $ 16,476 $ — $ — $ — $ 371,725 $ 13,653 $ 16,476 $ 371,725 $ 13,653 $ (23,423) 2017 Ashburn, Virginia (DC-2) — — 20,603 — — 109,254 — — 129,857 — 2019 Ashburn, Virginia (DC-3) (2) — — 35,198 — — 7,194 — — 42,392 — 2017 Atlanta, Georgia (DC-1) 2,078 35,473 2,209 11,212 538,751 991 13,289 574,224 3,200 (221,800) 2006 Atlanta, Georgia (DC-2) 10,569 — — — 124,864 124,252 10,569 124,864 124,252 (2,737) 2017 Atlanta, Georgia Land (2) 23,572 — 52,754 7,726 1,054 10,866 31,298 1,054 63,619 (449) 2017, 2019, 2020 Chicago, Illinois — — 17,764 9,400 250,335 86,353 9,400 250,335 104,117 (34,134) 2014 Dulles, Virginia 3,154 29,583 — — 24,740 (3) 4,148 3,154 54,323 4,148 (17,191) 2017 Eemshaven, Netherlands — — 29,915 5,366 21,712 17,616 5,366 21,712 47,531 (1,017) 2019 Fort Worth, Texas 136 610 48,984 8,943 123,444 (47,920) 9,079 124,054 1,064 (8,967) 2016 Groningen, Netherlands 1,743 8,640 — 153 2,566 3,730 1,896 11,206 3,730 (1,456) 2019 Hillsboro, Oregon — — 25,657 18,414 34,594 52,733 18,414 34,594 78,390 (880) 2017 Irving, Texas — 5,808 — 8,606 386,467 99,591 8,606 392,275 99,591 (81,213) 2013 Lenexa, Kansas 400 3,100 — 37 781 — 437 3,881 — (703) 2011 Manassas, Virginia (DC-1) (2) — — 27,484 — 25 33,586 — 25 61,070 (2) 2018 Manassas, Virginia (DC-2) — — 5,911 — — 92 — — 6,003 — 2018 Miami, Florida 1,777 6,955 — — 24,934 577 1,777 31,889 577 (13,796) 2008 Phoenix, Arizona (2) — — 24,668 — — 13,061 — — 37,729 — 2017 Piscataway, New Jersey 7,466 80,366 13,900 — 41,810 16,501 7,466 122,176 30,401 (16,600) 2016 Princeton, New Jersey 20,700 32,126 — — 3,135 5 20,700 35,261 5 (6,319) 2014 Richmond, Virginia 2,000 11,200 7,029 180 222,727 113,548 2,180 233,927 120,577 (84,389) 2010 & 2019 Sacramento, California 1,481 52,753 — — 13,546 12 1,481 66,299 12 (16,325) 2012 San Antonio, Texas (2) — — 37,167 — — 3,213 — — 40,380 — 2020 Santa Clara, California — 15,838 — — 101,505 9,385 — 117,343 9,385 (52,742) 2007 Suwanee, Georgia (Atlanta-Suwanee) 1,395 29,802 — 2,126 154,665 6,701 3,521 184,467 6,701 (90,323) 2005 $ 92,947 $ 312,254 $ 349,243 $ 72,162 $ 2,443,381 $ 679,142 $ 165,109 $ 2,755,635 $ 1,028,385 $ (674,468) Leased Properties Jersey City, New Jersey — 1,985 — — 28,178 223 — 30,163 223 (15,455) 2006 Leased Facilities acquired in 2015 — 59,087 — — (6,491) 2 — 52,596 2 (12,513) 2015 Overland Park, Kansas — — — — 866 154 — 866 154 (508) $ — $ 61,072 $ — $ — $ 22,553 $ 379 $ — $ 83,625 $ 379 $ (28,476) $ 92,947 $ 373,326 $ 349,243 $ 72,162 $ 2,465,934 $ 679,521 $ 165,109 $ 2,839,260 $ 1,028,764 $ (702,944) (1) See Note 2 - ‘Summary of Significant Accounting Policies’ for information regarding asset lives on which depreciation and amortization are calculated. (2) Represent land purchases. Land acquisition costs, as well as subsequent development costs, are included within construction in progress until development on the land has ended and the asset is ready for its intended use. (3) Includes the effects of an impairment recognized during the year ended December 31, 2019 of certain data center assets and equipment in one of our Dulles, Virginia data centers. The impairment resulted in a reduction of costs capitalized of $24.9 million as well as a reduction of accumulated depreciation of $13.5 million during the year ended December 31, 2019. See the Impairment of Long-Lived Assets, Intangible Assets and Goodwill section of Note 2 ‘Summary of Significant Accounting Policies’ for additional information. The aggregate gross cost of the Company’s properties for U.S. federal income tax purposes was $4.22 billion (unaudited) as of December 31, 2020. The following table reconciles the historical cost and accumulated depreciation for the years ended December 31, 2020, 2019 and 2018 (in thousands): Year Ended December 31, 2020 2019 2018 Property Balance, beginning of period $ 3,230,428 $ 2,812,856 $ 2,357,322 Disposals (7,821) (41,363) (43,616) Additions (acquisitions and improvements) 810,527 458,935 499,150 Balance, end of period $ 4,033,134 $ 3,230,428 $ 2,812,856 Accumulated depreciation Balance, beginning of period $ (558,560) $ (467,644) $ (394,823) Disposals 6,577 28,172 30,139 Additions (depreciation and amortization expense) (150,961) (119,088) (102,960) Balance, end of period $ (702,944) $ (558,560) $ (467,644)

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2020
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation – The accompanying financial statements have been prepared by management in accordance with accounting principles generally accepted in the United States (“U.S. GAAP”). In the opinion of management, all adjustments (consisting of normal recurring adjustments) considered necessary for a fair presentation have been included. References to “QTS” mean QTS Realty Trust, Inc. and its controlled subsidiaries and references to the “Operating Partnership” mean QualityTech, LP and its controlled subsidiaries. The Operating Partnership meets the definition and criteria of a variable interest entity (“VIE”) in accordance with Accounting Standards Codification ("ASC") Topic 810 Consolidation , and the Company is the primary beneficiary of the VIE. As discussed below, the Company’s only material asset is its ownership interest in the Operating Partnership, and consequently, all of its assets and liabilities represent those assets and liabilities of the Operating Partnership. The Company’s debt is an obligation of the Operating Partnership where the creditors may have recourse, under certain circumstances, against the credit of the Company. QTS is the sole general partner of the Operating Partnership, and its only material asset consists of its ownership interest in the Operating Partnership. Management operates QTS and the Operating Partnership as one business. The management of QTS consists of the same employees as the management of the Operating Partnership. QTS does not conduct business itself, other than acting as the sole general partner of the Operating Partnership and issuing public equity from time to time. QTS has not issued or guaranteed any indebtedness. Except for net proceeds from public equity issuances by QTS, which are contributed to the Operating Partnership in exchange for units of limited partnership interest of the Operating Partnership, the Operating Partnership generates all remaining capital required by the business through its operations, the direct or indirect incurrence of indebtedness, and the issuance of partnership units. Therefore, as general partner with control of the Operating Partnership, QTS consolidates the Operating Partnership for financial reporting purposes. Obligations under the 3.875% Senior Notes due 2028 and the unsecured credit facility, both discussed in Note 8, are fully, unconditionally, and jointly and severally guaranteed by the Operating Partnership’s existing subsidiaries (other than certain foreign subsidiaries and receivables entities) and future subsidiaries that guarantee any indebtedness of QTS Realty Trust, Inc., the Operating Partnership, QTS Finance Corporation (the co-issuer of the 3.875% Senior Notes due 2028) or any subsidiary guarantor. The indenture governing the 3.875% Senior Notes due 2028 restricts the ability of the Operating Partnership to make distributions to QTS, subject to certain exceptions, including distributions required in order for QTS to maintain its status as a real estate investment trust under the Internal Revenue Code of 1986, as amended (the “Code”).
Use of Estimates	Use of Estimates – The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, 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. Significant items subject to such estimates and assumptions include the useful lives of fixed assets, allowances for doubtful accounts and deferred tax assets and the valuation of derivatives, real estate assets, acquired intangible assets and certain accruals. The impacts of the COVID-19 pandemic increases uncertainty, which has reduced our ability to use past results to estimate future performance. Accordingly, our estimates and judgments may be subject to greater volatility than has been the case in the past.
Principles of Consolidation	Principles of Consolidation – The consolidated financial statements of QTS Realty Trust, Inc. include the accounts of QTS Realty Trust, Inc. and its controlled subsidiaries. All significant intercompany accounts and transactions have been eliminated in the financial statements. We evaluate our investments in less than wholly owned entities to determine whether they should be recorded on a consolidated basis. The percentage of ownership interest in the entity, an evaluation of control and whether a VIE exists are all considered in our consolidation assessment. Investments in real estate entities which we have the ability to exercise significant influence, but do not have financial or operating control, are accounted for using the equity method of accounting. Accordingly, our share of the earnings or losses of these entities is included in consolidated net income (loss).
Variable Interest Entities (VIEs)	Variable Interest Entities (VIEs) – We determine whether an entity is a VIE and, if so, whether it should be consolidated by utilizing judgments and estimates that are inherently subjective. The determination of whether an entity in which we hold a direct or indirect variable interest is a VIE is based on several factors, including whether the entity’s total equity investment at risk upon inception is sufficient to finance the entity’s activities without additional subordinated financial support. We make judgments regarding the sufficiency of the equity at risk based first on a qualitative analysis, and then a quantitative analysis, if necessary. We analyze any investments in VIEs to determine if we are the primary beneficiary. In evaluating whether we are the primary beneficiary, we evaluate our direct and indirect economic interests in the entity. Determining which reporting entity, if any, is the primary beneficiary of a VIE is primarily a qualitative approach focused on identifying which reporting entity has both (1) the power to direct the activities of a VIE that most significantly impact such entity’s economic performance and (2) the obligation to absorb losses or the right to receive benefits from such entity that could potentially be significant to such entity. Performance of that analysis requires the exercise of judgment. We consider a variety of factors in identifying the entity that holds the power to direct matters that most significantly impact the VIE’s economic performance including, but not limited to, the ability to direct financing, leasing, construction and other operating decisions and activities. In addition, we consider the rights of other investors to participate in those decisions, to replace the manager and to sell or liquidate the entity. We determine whether we are the primary beneficiary of a VIE at the time we become involved with a variable interest entity and reconsider that conclusion upon a reconsideration event. As of December 31, 2020, we had one unconsolidated entity that was considered a VIE for which we are not the primary beneficiary. Our maximum exposure to losses associated with this VIE is limited to our net investment, which was approximately $22.6 million as of December 31, 2020.
Real Estate Assets	Real Estate Assets – Real estate assets are reported at cost. All capital improvements for the income-producing properties that extend their useful lives are capitalized to individual property improvements and depreciated over their estimated useful lives. Depreciation for real estate assets is generally provided on a straight-line basis over 40 years from the date the property was placed in service. Property improvements are depreciated on a straight-line basis over the life of the respective improvement ranging from 20 to 40 years from the date the components were placed in service. Leasehold improvements are depreciated over the lesser of 20 years or through the end of the respective life of the lease. Repairs and maintenance costs are expensed as incurred. For the year ended December 31, 2020, depreciation expense related to real estate assets and non-real estate assets was $147.8 million and $13.4 million, respectively, for a total of $161.2 million. For the year ended December 31, 2019, depreciation expense related to real estate assets and non-real estate assets was $118.9 million and $11.9
Acquisitions and Sales	Acquisitions and Sales – Acquisitions of real estate and other entities are either accounted for as asset acquisitions or business combinations depending on facts and circumstances. When substantially all of the fair value of gross assets acquired is concentrated in a single identifiable asset or a group of similar identifiable assets, the transaction is accounted for as an asset acquisition. In an asset acquisition, the purchase price paid for assets acquired is allocated between identified tangible and intangible assets acquired based on relative fair value. Transaction costs associated with asset acquisitions are capitalized. When substantially all of the fair value of assets acquired is not concentrated in a group of similar identifiable assets, the set of assets will generally be considered a business. When accounting for business combinations, purchase accounting is applied to the assets and liabilities related to all real estate investments acquired in accordance with the accounting requirements of ASC Topic 805, Business Combinations , which requires the recording of net assets of acquired businesses at fair value. The fair value of the consideration transferred is assigned to the acquired tangible assets, consisting primarily of land, construction in progress, building and improvements, and identified intangible assets and liabilities, consisting of the value of above-market and below-market leases, value of in-place leases, value of customer relationships, and finance leases. The excess of the fair value of liabilities assumed, common stock issued and cash paid over the fair value of identifiable assets acquired is allocated to goodwill, which is not amortized. Transaction costs associated with business combinations are expensed as incurred. In developing estimates of fair value of acquired assets and assumed liabilities, management analyzes a variety of factors including market data, estimated future cash flows of the acquired operations, industry growth rates, current replacement cost for fixed assets and market rate assumptions for contractual obligations. Such a valuation requires management to make significant estimates and assumptions, particularly with respect to the intangible assets. Acquired in-place leases are amortized as amortization expense on a straight-line basis over the remaining life of the underlying leases. Acquired customer relationships are amortized as amortization expense on a straight-line basis over the expected life of the customer relationship. These amortization expenses are accounted for as real estate amortization expense. Above or below market leases are amortized on a straight-line basis over their expected lives and are recorded as a reduction to or increase in rental revenue when we are the lessor as well as a reduction to or increase in rent expense over the remaining lease terms when we are the lessee. We account for the sale of assets to non-customers under Financial Accounting Standards Board (“FASB”) ASU No. 2017-5, Other Income—Gains and Losses from the Derecognition of Nonfinancial Assets (Subtopic 610-20), which provides for recognition or derecognition based on transfer of ownership. During the year ended December 31, 2019, we sold our Manassas facility to an unconsolidated entity in exchange for cash consideration and noncash consideration in the form of an equity interest in the unconsolidated entity. After measuring the consideration received at fair value, we recognized a $13.4 million gain on sale of real estate, net of approximately $5.8 million of transaction costs, associated with our contribution of certain assets in our Manassas facility to the unconsolidated entity. Substantially all of the fair value of the assets contributed to the entity was concentrated in a group of similar identifiable assets and the sale of the assets were not to a customer, therefore the transaction was accounted for as an asset sale. The gain on sale of real estate is included within the “Gain on sale of real estate, net” line item of the consolidated statements of operations. In addition, during the year ended December 31, 2019, we recognized a $1.4 million gain on sale of certain land and improvements near our Atlanta (DC-1) (formerly known as Atlanta-Metro) facility which is included within the “Gain on sale of real estate, net” line item of the consolidated statements of operations. During the year ended December 31, 2018, we recognized a $7.0 million net loss on sale of equipment associated with our strategic growth plan which was included within the “Restructuring” line item of the consolidated statements of operations.
Impairment of Long-Lived Assets, Intangible Assets and Goodwill	Impairment of Long-Lived Assets, Intangible Assets and Goodwill – We review our long-lived assets, intangible assets and equity method investments for impairment when events or changes in circumstances indicate that the carrying amount of the assets may not be recoverable. Recoverability of assets to be held and used is measured by comparison of the carrying amount to the future net cash flows, undiscounted and without interest, expected to be generated by the asset group. If the net carrying value of the asset group exceeds the value of the undiscounted cash flows, the fair value of the asset group is assessed and may be considered impaired. An impairment loss is recognized based on the excess of the carrying amount of the impaired asset over its fair value. No impairment losses were recorded for the year ended December 31, 2020. For the year ended December 31, 2019, we recognized an $11.5 million impairment loss related to the write-down of certain data center assets and equipment in one of our Dulles, Virginia data centers. The Dulles campus has two data center buildings and we initiated a plan in the fourth quarter of 2019 to abandon one of the buildings and relocate customers from the smaller and older facility being abandoned to the newer facility in an effort to better optimize our operating cost structure. The impairment loss was included within the “Transaction, integration and impairment costs” line item of the consolidated statements of operations. For the year ended December 31, 2018, we recognized $8.8 million of impairment losses related to certain product-related assets, which was included in the “Restructuring” line item of the consolidated statements of operations. The fair value of goodwill is the consideration transferred in a business combination which is not allocable to identifiable intangible and tangible assets. Goodwill is subject to at least an annual assessment for impairment. In connection with the goodwill impairment evaluation that we performed as of October 1, 2020, we determined qualitatively that it is not more likely than not that the fair value of our one reporting unit was less than the carrying amount, thus we did not perform a quantitative analysis. As we continue to operate and assess our goodwill at the consolidated level for our single reporting unit and our market capitalization significantly exceeds our net asset value, further analysis was not deemed necessary as of December 31, 2020.
Cash and Cash Equivalents	Cash and Cash Equivalents – We consider all demand deposits and money market accounts purchased with a maturity date of three months or less at the date of purchase to be cash equivalents. Our account balances at one or more institutions periodically exceed the Federal Deposit Insurance Corporation (“FDIC”) insurance coverage and, as a result, there is concentration of credit risk related to amounts on deposit in excess of FDIC coverage. We mitigate this risk by depositing a majority of our funds with several major financial institutions. We also have not experienced any losses and do not believe that the risk is significant.
Deferred Costs	Deferred Costs – Deferred costs, net, on our balance sheets include both deferred financing costs and deferred leasing costs. Deferred financing costs represent fees and other costs incurred in connection with obtaining debt and are amortized over the term of the loan and are included in interest expense. Debt issuance costs related to revolving debt arrangements are deferred and presented as assets on the balance sheet; however, all other debt issuance costs are recorded as a direct offset to the associated liability. Amortization of debt issuance costs, including those costs presented as offsets to the associated liability in the consolidated balance sheets, were $4.1 million, $3.9 million and $3.9 million for the years ended December 31, 2020, 2019 and 2018, respectively. During the year ended December 31, 2020, we wrote off unamortized financing costs of $3.7 million primarily in connection with the early extinguishment of the $400 million 4.750% senior notes due 2025. During the year ended December 31, 2019, we wrote off unamortized financing costs of $1.5 million in connection with the modification of our unsecured credit facility in October 2019 whereby we added a seven Deferred financing costs presented as assets on the balance sheets related to revolving debt arrangements, net of accumulated amortization are as follows: (dollars in thousands) December 31, December 31, Deferred financing costs $ 13,786 $ 13,776 Accumulated amortization (7,752) (5,743) Deferred financing costs, net $ 6,034 $ 8,033 Deferred financing costs presented as offsets to the associated liabilities on the balance sheets related to fixed debt arrangements, net of accumulated amortization, are as follows: (dollars in thousands) December 31, December 31, Deferred financing costs $ 19,327 $ 15,777 Accumulated amortization (4,765) (4,937) Deferred financing costs, net $ 14,562 $ 10,840 Initial direct costs, or deferred leasing costs, include commissions paid to third parties, including brokers, leasing and referral agents, and internal sales commissions paid to employees for successful execution of lease agreements and are accounted for pursuant to ASC Topic 842, Leases . These costs are incurred when we execute lease agreements and represent only incremental costs that would not have been incurred if the lease agreement had not been executed. To a lesser extent, we incur the same incremental costs to obtain managed services contracts with customers that are accounted for pursuant to ASC Topic 606, Revenue from Contracts with Customers . Because the framework of accounting for these costs and the underlying nature of the costs are the same for our revenue and lease contracts, the costs are presented on a combined basis within our financial statements and within the below table. Both revenue and leasing commissions are capitalized and generally amortized over the term of the related leases or the expected term of the contract using the straight-line method. If a customer lease terminates prior to the expiration of its initial term, any unamortized initial direct costs related to the lease are written off to amortization expense. Amortization of deferred leasing costs totaled $26.1 million, $24.2 million and $21.3 million for the years ended December 31, 2020, 2019 and 2018, respectively. Deferred leasing costs, net of accumulated amortization are as follows: (dollars in thousands) December 31, December 31, Deferred leasing costs $ 101,480 $ 77,178 Accumulated amortization (43,825) (32,848) Deferred leasing costs, net $ 57,655 $ 44,330
Revenue Recognition	Revenue Recognition – We derive our revenues from leases with customers for data center space which include lease components and nonlease revenue components, such as power, tenant recoveries, and managed services. We adopted ASC Topic 842, Leases , the new accounting standard for leases, effective January 1, 2019 using the modified retrospective approach. We have elected the available practical expedient under ASC Topic 842, Leases , to combine our nonlease revenue components that have the same pattern of transfer as the related operating lease component into a single combined lease component. The single combined component is accounted for under ASC Topic 842 if the lease component is the predominant component and is accounted for under ASC Topic 606 if the nonlease components are the predominant components. In our contracts, the single combined component is accounted for under ASC Topic 842 as the lease component is the predominant component. A description of each of our disaggregated revenue streams is as follows: Rental Revenue Our leases with customers are classified as operating leases and rental revenue is recognized on a straight-line basis over the customer lease term. Occasionally, customer leases include options to extend or terminate the lease agreements. We do not include any of these extension or termination options in a customer’s lease term for lease classification purposes or recognizing rental revenue unless it is reasonably certain the customer will exercise these extension or termination options. Rental revenue also includes revenue from power delivery on fixed power arrangements, whereby customers are billed and pay a fixed monthly fee per committed available amount of connected power. These fixed power arrangements require us to provide a series of distinct services and to stand ready to deliver the power over the contracted term which is co-terminus with the lease. Customer fixed power arrangements have the same pattern of transfer over the lease term as the lease component and are therefore combined with the lease component to form a single lease component that is recognized over the term of the lease on a straight-line basis. In addition, rental revenue includes straight line rent. Straight line rent represents the difference in rents recognized during the period versus amounts contractually due pursuant to the underlying leases and is recorded as deferred rent receivable/payable in the consolidated balance sheets. For lease agreements that provide for scheduled rent increases, rental income is recognized on a straight-line basis over the non-cancellable term of the leases, which commences when control of the space has been provided to the customer. The amount of the straight-line rent receivable on the balance sheets included in rents and other receivables, net was $63.6 million and $38.7 million as of December 31, 2020 and December 31, 2019, respectively. Rental revenue also includes amortization of set-up fees which are amortized over the term of the respective lease as discussed below in the "Deferred Income" section. Variable Lease Revenue from Recoveries Certain customer leases contain provisions under which customers reimburse us for power and cooling-related charges as well as a portion of the property’s real estate taxes, insurance and other operating expenses. Recoveries of power and cooling-related expenses relate specifically to our variable power arrangements, whereby customers pay variable monthly fees for the specific amount of power utilized at the current utility rates. Our performance obligation is to stand ready to deliver power over the life of the customer contract up to a contracted power capacity. Customers have the flexibility to increase or decrease the amount of power consumed, and therefore sub-metered power revenue is constrained at contract inception. The reimbursements are included in revenue as recoveries from customers and are recognized each month as the uncertainty related to the consideration is resolved (i.e. we provide power to our customers) and customers utilize the power. Reimbursement of real estate taxes, insurance, common area maintenance, or other operating expenses are accounted for as variable payments under lease guidance pursuant to the practical expedient and are recognized as revenue in the period that the expenses are recognized. Variable lease revenue from recoveries discussed above, including power, common area maintenance or other operating costs, have the same pattern of transfer over the lease term as the lease component and are therefore combined with the lease component to form a single lease component. Variable lease revenue from recoveries is included within the “rental” line item on the statements of operations. Other Revenue Other revenue primarily consists of revenue from our managed service offerings as well as revenue earned from partner channel, management and development fees. We, through our TRS, may provide use of our managed services to our customers on an individual or combined basis. In our managed services offering the TRS’s performance obligation is to provide services (e.g. cloud hosting, data backup, data storage or data center personnel labor hours) to facilitate a fully integrated information technology (“IT”) outsourcing environment over a contracted term. Although underlying services may vary, over the contracted term monthly service offerings are substantially the same and we account for the services as a series of distinct services in accordance with ASC Topic 606. Service fee revenue is recognized as the revenue is earned, which generally coincides with the services being provided. As we have the right to consideration from customers in an amount that corresponds directly with the value to the customer of the TRS’s performance of providing continuous services, we recognize monthly revenue for the amount invoiced. With respect to the transaction price allocated to remaining performance obligations within our managed service contracts, we have elected to use the optional exemption provided by ASC Topic 606 whereby we are not required to estimate the total transaction price allocated to remaining performance obligations as we apply the “right-to-invoice” practical expedient. As described above, the nature of our performance obligation in these contracts is to provide monthly services that are substantially the same and accounted for as a series of distinct services. These contracts generally have a remaining term ranging from month-to-month to three years. Management fees and other revenues are generally received from our unconsolidated entity properties as well as third parties. Management fee revenue is earned based on a contractual percentage of unconsolidated entity property revenue. Development fee revenue is earned on a contractual percentage of hard costs to develop a property. We recognize revenue for these services provided when earned based on the performance criteria in ASC Topic 606, with such revenue recorded in “Other” revenue on the consolidated statements of operations.
Allowance for Uncollectible Accounts Receivable	Allowance for Uncollectible Accounts Receivable – We record a provision for uncollectible accounts if a receivable balance relating to lease components from an individual contract is considered by management not to be probable of collection, and this provision is recorded as a reduction to leasing revenues. We also record a general provision of estimated uncollectible tenant receivables based on general probability of collection in accordance with ASC 450-20 Loss Contingencies . This provision is recorded as bad debt expense and recorded within the “Property Operating Costs” line item of the consolidated statements of operations. The aggregate allowance for doubtful accounts on the consolidated balance sheets was $5.4 million and $2.3 million as of December 31, 2020 and December 31, 2019, respectively.
Advance Rents and Security Deposits	Advance Rents and Security Deposits – Advance rents, typically prepayment of the following month’s rent, consist of payments received from customers prior to the time they are earned and are recognized as revenue in subsequent periods when earned. Security deposits are collected from customers at the lease origination and are generally refunded to customers upon lease expiration.
Deferred Income	Deferred Income – Deferred income generally results from non-refundable charges paid by the customer at lease inception to prepare their space for occupancy. We record this initial payment, commonly referred to as set-up fees, as a deferred income liability which amortizes into rental revenue over the term of the related lease on a straight-line basis.
Foreign Currency	Foreign Currency - The financial position of foreign subsidiaries whose functional currency is not the U.S. dollar is translated at the exchange rates in effect at the end of the period, while revenues and expenses are translated at average exchange rates during the period. Gains or losses from translation of foreign operations where the local currency is the functional currency are included as components of other comprehensive income (loss). Prior to February 2020, gains or losses from foreign currency transactions were included in determining net income (loss). In February 2020, we entered into a net investment hedge which resulted in gains or losses subsequently being recognized in Other Comprehensive Income (Loss).
Equity-based Compensation	Equity-based Compensation – Equity-based compensation costs are measured based upon their estimated fair value on the date of grant or modification and amortized ratably over their respective service periods. We have elected to account for forfeitures as they occur. Equity-based compensation expense was $27.0 million, $16.4 million, and $18.1 million for the years ended December 31, 2020, 2019 and 2018, respectively. Equity based compensation expense for the year ended December 31, 2020 includes $1.8 million of equity-based compensation expense associated with the revaluation and acceleration of equity awards related to an executive officer's retirement which is included within the "Transaction, integration, and impairment costs" line item of the consolidated statements of operations. Equity-based compensation expense for the year ended December 31, 2018 includes $3.1 million of equity-based compensation associated with the acceleration of equity awards related to certain employees impacted by the Company’s strategic growth plan which was included in the “Restructuring” expense line item on the consolidated statements of operations.
Segment Information	Segment Information – We manage our business as one operating segment and thus one reportable segment consisting of a portfolio of investments in multiple data centers.
Customer Concentrations	Customer Concentrations – During the year ended December 31, 2020, one of our customers exceeded 10% of total revenues, representing approximately 11.8% of total revenues for the year ended December 31, 2020. As of December 31, 2020, two of our customers exceeded 5% of trade accounts receivable. In aggregate, these two customers accounted for approximately 45.0% of trade accounts receivable. One of these customers individually exceeded 10% of total trade accounts receivable representing 39.2% of total trade accounts receivable.
Distribution Policy	Distribution Policy To satisfy the requirements to qualify for taxation as a REIT, and to avoid paying tax on our income, we intend to continue to make regular quarterly distributions of all, or substantially all, of our REIT taxable income (excluding net capital gains) to our stockholders. All distributions will be made at the discretion of our board of directors and will depend on our historical and projected results of operations, liquidity and financial condition, our REIT qualification, our debt service requirements, operating expenses and capital expenditures, prohibitions and other restrictions under financing arrangements and applicable law and other factors as our board of directors may deem relevant from time to time. We anticipate that our estimated cash available for distribution will exceed the annual distribution requirements applicable to REITs and the amount necessary to avoid the payment of tax on undistributed income. However, under some circumstances, we may be required to make distributions in excess of cash available for distribution in order to meet these distribution requirements and we may need to borrow funds to make certain distributions. If we borrow to fund distributions, our future interest costs would increase, thereby reducing our earnings and cash available for distribution from what they otherwise would have been. The partnership agreement of the Operating Partnership requires the Operating Partnership to distribute at least quarterly 100% of our “available cash” (as defined in the partnership agreement) to the partners of the Operating Partnership, in accordance with the terms established for the class of partnership interests held by such partner. Furthermore, because QTS intends to continue to qualify as a REIT for tax purposes, QTS is required to make reasonable efforts to distribute available cash (a) to limited partners of the Operating Partnership so as to preclude any such distribution or portion thereof from being treated as part of a sale of property to the Operating Partnership by a limited partner under Section 707 of the Code or the regulations thereunder; provided, however, that neither of QTS nor the Operating Partnership shall have liability to a limited partner under any circumstances as a result of any distribution to a limited partner being so treated, and (b) to QTS, its general partner, in an amount sufficient to enable QTS to make distributions to its stockholders that will enable QTS to (1) satisfy the requirements for qualification as a REIT under the Code and the regulations thereunder, and (2) avoid any U.S. federal income or excise tax liability. Consistent with the partnership agreement, we intend to continue to distribute quarterly an amount of our available cash sufficient to enable QTS to pay quarterly dividends to its stockholders in an amount necessary to satisfy the requirements applicable to REITs under the Code and to eliminate U.S. federal income and excise tax liability.
Fair Value Measurements	Fair Value Measurements – ASC Topic 820, Fair Value Measurement , emphasizes that fair-value is a market-based measurement, not an entity-specific measurement. Therefore, a fair-value measurement should be determined based on the assumptions that market participants would use in pricing the asset or liability. As a basis for considering market participant assumptions in fair-value measurements, a fair-value hierarchy is established that distinguishes between market participant assumptions based on market data obtained from sources independent of the reporting entity (observable inputs that are classified within Levels 1 and 2 of the hierarchy) and the reporting entity’s own assumptions about market participant assumptions (unobservable inputs classified within Level 3 of the hierarchy). Level 1 inputs utilize quoted prices (unadjusted) in active markets for identical assets or liabilities that we have the ability to access. Level 2 inputs are inputs other than quoted prices included in Level 1 that are observable for the asset or liability, either directly or indirectly. Level 2 inputs may include quoted prices for similar assets and liabilities in active markets, as well as inputs that are observable for the asset or liability (other than quoted prices), such as interest rates, foreign exchange rates, and yield curves that are observable at commonly quoted intervals. Level 3 inputs are unobservable inputs for the asset or liability, which are typically based on an entity’s own assumptions, as there is little, if any, related market activity. In instances where the determination of the fair-value measurement is based on inputs from different levels of the fair-value hierarchy, the level in the fair-value hierarchy within which the entire fair-value measurement falls is based on the lowest level input that is significant to the fair-value measurement in its entirety. Our assessment of the significance of a particular input to the fair-value measurement in its entirety requires judgment, and considers factors specific to the asset or liability. As of December 31, 2020, we valued our derivative instruments primarily utilizing Level 2 inputs. See Note 18 – ‘Fair Value of Financial Instruments’ for additional details.
Recently Adopted Accounting Standards	New Accounting Pronouncements In June 2016, the FASB issued ASU 2016-13, Financial Instruments – Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments , and subsequent amendments to the guidance: ASU 2018-19 in November 2018, ASU 2019-4 in April 2019, ASU 2019-5 in May 2019, ASUs 2019-10 & 2019-11 in November 2019, and ASU 2020-2 in February 2020. The standard, as amended, requires entities to use a new impairment model based on current expected credit losses (“CECL”) rather than incurred losses. The CECL model is designed to capture expected credit losses through the establishment of an allowance account, which will be presented as an offset to the amortized cost basis of the related financial asset. The guidance is effective for interim and annual periods beginning after December 15, 2019. We adopted this ASU effective January 1, 2020. As the majority of our revenue is generated from operating leases which are governed under ASC Topic 842, the provisions of this standard did not have a material impact on our consolidated financial statements. In January 2020, the FASB issued ASU 2020-1, Investments—Equity Securities (Topic 321), Investments—Equity Method and Joint Ventures (Topic 323), and Derivatives and Hedging (Topic 815): Clarifying the Interactions between Topic 321, Topic 323, and Topic 815 , which clarifies the interaction between the accounting for equity securities under Topic 321, the accounting for equity method investments in Topic 323, and the accounting for certain forward contracts and purchased options in Topic 815. ASU 2020-1 is effective for fiscal years beginning after December 15, 2020, and interim periods within those fiscal years. Early adoption is permitted. The amendments in this Update should be applied prospectively. We do not expect the provisions of the standard will have a material impact on our consolidated financial statements when adopted. In March 2020, the FASB issued ASU 2020-4, Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting . ASU 2020-4 contains practical expedients for reference rate reform related activities that impact debt, leases, derivatives and other contracts. The guidance in ASU 2020-4 is optional and may be elected over time as reference rate reform activities occur. The standard is effective for all entities as of March 12, 2020 through December 31, 2022. An entity can elect to apply the amendments as of any date from the beginning of an interim period that includes or is subsequent to March 12, 2020, or prospectively from a date within an interim period that includes or is subsequent to March 12, 2020, up to that date that the financial statements are available to be issued. Beginning in the first quarter of 2020, we have elected to apply the hedge accounting expedients related to probability and the assessments of effectiveness for future LIBOR-indexed cash flows to assume that the index upon which future hedged transactions will be based matches the index on the corresponding derivatives. Application of these expedients preserves the presentation of derivatives consistent with past presentation. We continue to evaluate the impact of the guidance but we do not expect the provisions of the standard will have a material impact on our consolidated financial statements. We determined all other recently issued accounting pronouncements will not have a material impact on our consolidated financial statements or do not materially apply to our operations.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2020
Deferred financing costs, net of accumulated amortization	(dollars in thousands) December 31, December 31, Deferred financing costs $ 13,786 $ 13,776 Accumulated amortization (7,752) (5,743) Deferred financing costs, net $ 6,034 $ 8,033
Deferred leasing costs, net of accumulated amortization	(dollars in thousands) December 31, December 31, Deferred leasing costs $ 101,480 $ 77,178 Accumulated amortization (43,825) (32,848) Deferred leasing costs, net $ 57,655 $ 44,330
Fixed debt arrangements
Deferred financing costs, net of accumulated amortization	(dollars in thousands) December 31, December 31, Deferred financing costs $ 19,327 $ 15,777 Accumulated amortization (4,765) (4,937) Deferred financing costs, net $ 14,562 $ 10,840

Acquisitions and Sales (Tables)

Acquisitions and Sales (Tables)	12 Months Ended
	Dec. 31, 2020
Business Combinations [Abstract]
Schedule of the original allocation of the fair value of assets acquired and liabilities assumed in acquisition	The following table summarizes the consideration for the Netherlands facilities and the allocation of the fair value of assets acquired and liabilities assumed at the acquisition date (in thousands): Purchase Price Allocation Weighted Avg Remaining Useful Life (in years) Land $ 1,743 N/A Buildings and improvements 8,640 24 Construction in progress 29,902 N/A Acquired intangibles (In-place lease & above market lease) 2,911 3 Deferred costs 906 3 Other assets 128 3 Net Working Capital 554 N/A Total identifiable assets acquired 44,784 Acquired below market lease 284 3 Total liabilities assumed 284 Net identifiable assets acquired $ 44,500

Acquired Intangibles Assets and

Acquired Intangibles Assets and Liabilities (Tables)	12 Months Ended
	Dec. 31, 2020
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of carrying values for the major classes of intangible assets and liabilities	Summarized below are the carrying values for the major classes of intangible assets and liabilities (in thousands): December 31, 2020 December 31, 2019 Useful Lives Gross Accumulated Net Carrying Gross Accumulated Net Carrying Customer Relationships 12 years $ 95,705 $ (44,361) $ 51,344 $ 95,705 $ (36,411) $ 59,294 In-Place Leases 0.5 to 10 years 34,813 (26,812) 8,001 34,588 (22,522) 12,066 Solar Power Agreement (1) 17 years 13,747 (5,256) 8,491 13,747 (4,448) 9,299 Acquired Favorable Leases Acquired above market leases - as Lessor 0.5 to 8 years 5,070 (4,816) 254 5,035 (4,015) 1,020 Total Intangible Assets $ 149,335 $ (81,245) $ 68,090 $ 149,075 $ (67,396) $ 81,679 Solar Power Agreement (1) 17 years 13,747 (5,256) 8,491 13,747 (4,448) 9,299 Acquired Unfavorable Leases Acquired below market leases - as Lessor 2 to 4 years 1,117 (1,113) 4 1,092 (967) 125 Acquired above market leases - as Lessee 11 to 12 years 2,453 (1,199) 1,254 2,453 (983) 1,470 Total Intangible Liabilities (2) $ 17,317 $ (7,568) $ 9,749 $ 17,292 $ (6,398) $ 10,894 (1) Amortization related to the Solar Power Agreement asset and liability is recorded at the same rate and therefore has no net impact on the statements of operations. (2) Intangible liabilities are included within the “Advance rents, security deposits and other liabilities” line item of the consolidated balance sheets.
Schedule of estimated amortization of acquired favorable and unfavorable leases	Net Rental Revenue Net Rental Expense Decrease 2021 $ 164 $ (216) 2022 55 (216) 2023 25 (216) 2024 6 (216) 2025 — (216) Thereafter — (174) Total $ 250 $ (1,254)
Schedule of estimated amortization of all other identified intangible assets	Year Ending December 31, 2021 $ 10,634 2022 10,088 2023 10,084 2024 8,967 2025 7,978 Thereafter 11,594 Total $ 59,345

Real Estate Assets and Constr_2

Real Estate Assets and Construction in Progress (Tables)	12 Months Ended
	Dec. 31, 2020
Real Estate [Abstract]
Summary of cost of owned and leased properties by the company	The following is a summary of our cost of owned or leased properties as of December 31, 2020 and 2019 (in thousands): As of December 31, 2020: Property Location Land Buildings, Improvements and Equipment Construction in Progress Total Cost Atlanta, Georgia Campus (1) $ 55,157 $ 700,142 $ 191,072 $ 946,371 Ashburn, Virginia Campus (2) 16,476 371,725 185,903 574,104 Irving, Texas 8,606 392,275 99,591 500,472 Chicago, Illinois 9,400 250,336 104,117 363,853 Richmond, Virginia 2,180 233,927 120,577 356,684 Suwanee, Georgia (Atlanta-Suwanee) 3,521 184,467 6,718 194,706 Piscataway, New Jersey 7,466 122,176 30,401 160,043 Fort Worth, Texas 9,079 124,054 1,064 134,197 Hillsboro, Oregon 18,414 34,594 78,390 131,398 Santa Clara, California (3) — 117,343 9,385 126,728 Leased Facilities (4) — 82,759 225 82,984 Eemshaven, Netherlands 5,366 21,712 47,531 74,609 Sacramento, California 1,481 66,300 12 67,793 Manassas, Virginia (5) — 25 67,073 67,098 Dulles, Virginia 3,154 54,323 4,148 61,625 Princeton, New Jersey 20,700 35,261 5 55,966 Phoenix, Arizona (5) — — 37,729 37,729 Groningen, Netherlands 1,896 11,206 3,730 16,832 Other (6) 2,213 36,636 41,094 79,943 $ 165,109 $ 2,839,261 $ 1,028,765 $ 4,033,135 (1) The “Atlanta, Georgia Campus” includes both the existing data center Atlanta (DC-1) as well as the recently developed data center Atlanta, GA (DC-2) on land adjacent to the existing Atlanta, GA (DC-1) facility. (2) The “Ashburn, Virginia Campus” includes both the existing data center Ashburn, VA (DC-1) as well as new property development associated with the construction of a second data center Ashburn, VA (DC-2). (3) Owned facility subject to long-term ground sublease. (4) Includes 7 facilities. All facilities are leased, including one subject to a finance lease. (5) Represent land purchases. Land acquisition costs, as well as subsequent development costs, are included within construction in progress until development on the land has ended and the asset is ready for its intended use. (6) Consists of Miami, FL; Lenexa, KS; Overland Park, KS and additional land. As of December 31, 2019: Property Location Land Buildings, Improvements and Equipment Construction in Progress Total Cost Atlanta, Georgia Campus (1) $ 44,588 $ 525,300 $ 128,930 $ 698,818 Irving, Texas 8,606 369,727 98,170 476,503 Ashburn, Virginia (2) 16,476 156,396 189,375 362,247 Richmond, Virginia 2,180 195,684 139,948 337,812 Chicago, Illinois 9,400 205,026 86,878 301,304 Suwanee, Georgia (Atlanta-Suwanee) 3,521 174,124 5,559 183,204 Piscataway, New Jersey 7,466 103,553 36,056 147,075 Santa Clara, California (3) — 114,499 1,238 115,737 Fort Worth, Texas 9,079 55,018 35,722 99,819 Leased Facilities (4) — 85,225 1,241 86,466 Sacramento, California 1,481 65,258 163 66,902 Hillsboro, Oregon (2) — — 63,573 63,573 Manassas, Virginia (2) — — 57,662 57,662 Princeton, New Jersey 20,700 35,192 39 55,931 Dulles, Virginia 3,154 48,651 4,688 56,493 Eemshaven, Netherlands — — 37,267 37,267 Phoenix, Arizona (2) — — 31,265 31,265 Groningen, Netherlands 1,741 9,085 3,028 13,854 Other (5) 2,213 36,163 120 38,496 $ 130,605 $ 2,178,901 $ 920,922 $ 3,230,428 (1) The “Atlanta, Georgia Campus” includes both the existing data center Atlanta (DC-1) as well as new property development associated with construction of a second data center Atlanta (DC-2) on land adjacent to the existing Atlanta (DC-1) facility. (2) Represent land purchases. Land acquisition costs, as well as subsequent development costs, are included within construction in progress until development on the land has ended and the asset is ready for its intended use. (3) Owned facility subject to long-term ground sublease. (4) Includes 7 facilities. All facilities are leased, including one subject to a finance lease. (5) Consists of Miami, FL; Lenexa, KS; and Overland Park, KS facilities.

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2020
Leases [Abstract]
Schedule of components of lease expenses	Components of lease expense were as follows (in thousands): Year Ended December 31, 2020 2019 Finance lease cost: Amortization of assets $ 4,150 $ 3,535 Interest on lease liabilities 1,915 1,693 Operating lease expense: Operating lease cost 9,012 9,102 Variable lease cost 1,072 1,109 Sublease income (193) (187) Total lease costs $ 15,956 $ 15,252
Schedule of supplemental balance sheet information	Supplemental balance sheet information related to leases was as follows (in thousands, except lease term and discount rate): As of December 31, 2020 2019 Operating leases: Operating lease right-of-use assets $ 51,342 $ 57,141 Operating lease liabilities 58,005 64,416 Finance leases: Property and equipment, at cost 49,554 50,437 Accumulated amortization (8,864) (4,830) Property and equipment, net $ 40,690 $ 45,607 Finance lease liabilities $ 41,718 $ 45,141 Weighted average remaining lease term (in years): Operating leases 13.4 13.7 Finance leases 10.3 11.4 Weighted average discount rate: Operating leases 5.2 % 5.1 % Finance leases 4.3 % 4.3 %
Schedule of cash flow information and other information	Supplemental cash flow and other information related to leases was as follows (in thousands): Year Ended December 31, 2020 2019 Cash paid for amounts included in the measurement of lease liabilities: Operating cash flows for operating leases $ 12,048 $ 9,834 Operating cash flows for finance leases $ 1,914 $ 1,704 Financing cash flows for finance leases $ 2,579 $ 2,855
Schedule of maturities of operating lease liabilities	Maturities of lease liabilities, which exclude variable rent payments, are as follows (in thousands): December 31, 2020 Operating Leases Finance Leases 2021 $ 9,818 $ 4,446 2022 10,266 4,570 2023 10,393 4,707 2024 8,317 4,847 2025 8,036 4,992 Thereafter 40,872 28,902 Total Lease Payments $ 87,702 $ 52,464 Less: Imputed Interest 29,697 10,746 Total Lease Obligations $ 58,005 $ 41,718
Schedule of maturities of finance lease liabilities	Maturities of lease liabilities, which exclude variable rent payments, are as follows (in thousands): December 31, 2020 Operating Leases Finance Leases 2021 $ 9,818 $ 4,446 2022 10,266 4,570 2023 10,393 4,707 2024 8,317 4,847 2025 8,036 4,992 Thereafter 40,872 28,902 Total Lease Payments $ 87,702 $ 52,464 Less: Imputed Interest 29,697 10,746 Total Lease Obligations $ 58,005 $ 41,718
Schedule of components of lease revenue	The components of our lease revenue were as follows (in thousands): Year Ended December 31, 2020 2019 2018 Lease revenue: Minimum lease revenue $ 464,005 $ 409,157 $ 367,388 Variable lease revenue (primarily recoveries from customers) 55,853 55,966 46,232 Total lease revenue $ 519,858 $ 465,123 $ 413,620

Debt (Tables)

Debt (Tables)	12 Months Ended
	Dec. 31, 2020
Debt Disclosure [Abstract]
Outstanding debt including operating leases and lease financing obligations	Below is a listing of our outstanding debt, including finance leases, as of December 31, 2020 and 2019 (in thousands): Weighted Average Effective Interest Rate at December 31, 2020 (1) Maturity Date December 31, 2020 December 31, 2019 Unsecured Credit Facility Revolving Credit Facility 1.41 % December 17, 2023 $ 392,337 $ 317,028 Term Loan A 3.26 % December 17, 2024 225,000 225,000 Term Loan B 3.30 % April 27, 2025 225,000 225,000 Term Loan C 3.46 % October 18, 2026 250,000 250,000 Term Loan D 1.45 % January 15, 2026 250,000 — 4.750% Senior Notes 4.75 % November 15, 2025 — 400,000 3.875% Senior Notes 3.88 % October 1, 2028 500,000 — Lenexa Mortgage 4.10 % May 1, 2022 — 1,736 Finance Leases 4.33 % 2021 - 2038 41,718 45,140 2.85 % 1,884,055 1,463,904 Less net debt issuance costs (14,562) (10,839) Total outstanding debt, net $ 1,869,493 $ 1,453,065 (1) The coupon interest rates associated with Term Loan A, Term Loan B, and Term Loan C incorporate the effects of our interest rate swaps in effect as of December 31, 2020.
Annual remaining principal payment	The annual remaining principal payment requirements of our debt securities as of December 31, 2020 per the contractual maturities, excluding extension options and excluding operating and finance leases, are as follows (in thousands): Year ending December 31, 2021 $ — 2022 — 2023 392,337 2024 225,000 2025 225,000 Thereafter 1,000,000 Total $ 1,842,337

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2020
Income Tax Disclosure [Abstract]
Schedule of income tax provision from continuing operations	For the Year Ended December 31, 2020 2019 2018 Current: U.S. federal $ — $ — $ (50) U.S. State 368 298 395 Outside United States 7 13 78 Total Current 375 311 423 Deferred: U.S. federal 71 (276) (3,727) U.S. State (66) (71) (64) Outside United States 58 (1) — Total Deferred 63 (348) (3,791) Total $ 438 $ (37) $ (3,368)
Summary of temporary differences and carry forwards which give rise to the deferred tax assets and liabilities	For the Year Ended December 31, 2020 2019 2018 Deferred tax assets Net operating loss carryforwards $ 22,950 $ 20,218 $ 17,610 Deferred revenue and setup charges 1,062 1,299 3,171 Operating lease liabilities 1,904 2,266 — Property and equipment — 512 — Leases 400 — 1 Credits 300 300 287 Bad debt reserve 191 18 409 Intangibles 1,038 804 — Interest expense carryforward IRC Sec. 163(j) 1,164 2,782 2,253 Equity compensation 1,654 1,119 952 Other 857 257 582 Gross deferred tax assets 31,520 29,575 25,265 Deferred tax liabilities Property and equipment (616) — (3,089) Goodwill (3,042) (2,494) (1,953) Intangibles — (591) (11,910) Operating lease right-of-use assets (1,056) (1,261) — Prepaid commissions (774) (1,007) (956) Other (218) (224) (93) Gross deferred tax liabilities (5,706) (5,577) (18,001) Net deferred tax asset 25,814 23,998 7,264 Valuation allowance (26,624) (24,747) (8,361) Net deferred tax liability $ (810) $ (749) $ (1,097)
Schedule of differences between total Income tax or benefit and amount computed by applying the statutory income tax rate	For the Year Ended December 31, 2020 2019 2018 TRS Statutory rate applied to pre-tax loss $ (1,380) $ (12,991) $ (9,656) Permanent differences, net 248 16 97 State income tax, net of federal benefit (421) (2,868) (1,430) Foreign income tax 7 13 78 Federal and State rate change (1) (20) (146) Other 109 (110) 41 Valuation allowance increase 1,876 15,923 7,648 Total tax expense (benefit) $ 438 $ (37) $ (3,368) Effective tax rate (6.7) % 0.1 % 7.3 %

Derivative Instruments (Tables)

Derivative Instruments (Tables)	12 Months Ended
	Dec. 31, 2020
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of interest rate derivatives and their fair values	Interest rate derivatives and their fair values as of December 31, 2020 and 2019 were as follows (in thousands): Notional Amount Fixed One Month LIBOR rate per annum Fair Value December 31, 2020 December 31, 2019 Effective Date Expiration Date December 31, 2020 December 31, 2019 $ 25,000 $ 25,000 1.989 % January 2, 2018 December 17, 2021 $ (447) $ (209) 100,000 100,000 1.989 % January 2, 2018 December 17, 2021 (1,788) (837) 75,000 75,000 1.989 % January 2, 2018 December 17, 2021 (1,342) (627) 50,000 50,000 2.033 % January 2, 2018 April 27, 2022 (1,248) (545) 100,000 100,000 2.029 % January 2, 2018 April 27, 2022 (2,490) (1,081) 50,000 50,000 2.033 % January 2, 2018 April 27, 2022 (1,248) (545) 100,000 100,000 2.617 % January 2, 2020 December 17, 2023 (7,191) (4,007) 100,000 100,000 2.621 % January 2, 2020 April 27, 2024 (8,000) (4,324) 70,000 — 0.968 % March 2, 2020 October 18, 2026 (2,174) — 30,000 — 0.973 % March 2, 2020 October 18, 2026 (938) — 200,000 200,000 2.636 % December 17, 2021 December 17, 2023 (9,648) (3,939) 200,000 200,000 2.642 % April 27, 2022 April 27, 2024 (9,500) (3,802) 125,000 — 1.014 % December 17, 2023 December 17, 2024 (704) — 100,000 — 1.035 % December 17, 2023 December 17, 2024 (584) — 75,000 — 1.110 % December 17, 2023 October 18, 2026 (866) — 100,000 — 1.088 % April 27, 2024 April 27, 2025 (540) — 125,000 — 1.082 % April 27, 2024 April 27, 2025 (666) — 75,000 — 0.977 % April 27, 2024 October 18, 2026 (422) — $ (49,796) $ (19,916)
Schedule of power purchase agreement derivatives	Power purchase agreement derivatives and their fair values as of December 31, 2020 and 2019 were as follows (in thousands): Fair Value Counterparty Facility Effective Date Expiration Date December 31, 2020 December 31, 2019 Calpine Energy Solutions, LLC Piscataway 3/8/2019 2/28/2029 $ (2,162) $ (2,919) Calpine Energy Solutions, LLC Chicago 3/8/2019 2/28/2029 (1,764) (3,774) $ (3,926) $ (6,693)

Partners' Capital, Equity and_2

Partners' Capital, Equity and Incentive Compensation Plans (Tables)	12 Months Ended
	Dec. 31, 2020
Equity [Abstract]
Summary of award activity under equity incentive plans and related information	The following is a summary of award activity under the 2010 Equity Incentive Plan and 2013 Equity Incentive Plan and related information for the years ended December 31, 2020, 2019 and 2018: 2010 Equity Incentive Plan 2013 Equity Incentive Plan Numbers of Class O Weighted average exercise Weighted average fair value Options Weighted average exercise Weighted average fair value Restricted Stock / Deferred Stock Weighted average fair value at grant date TSR Units Weighted average fair value at grant date FFO Units Weighted average fair value at grant date Outstanding at January 1, 2018 568,040 $ 23.52 $ 5.00 1,369,270 $ 38.18 $ 7.80 381,864 $ 46.37 — $ — — $ — Granted — — — 674,081 34.05 5.63 348,152 35.27 — — — — Exercised/Vested (1) (465,761) 23.40 4.76 (6,188) 21.50 3.68 (224,660) 46.23 — — — — Cancelled/Expired — — — — — — (85,047) 43.50 — — — — Outstanding at December 31, 2018 102,279 $ 24.05 $ 5.67 2,037,163 $ 36.86 $ 7.10 420,309 $ 37.83 — $ — — $ — Granted — — — 135,594 42.27 7.62 274,564 42.25 86,089 54.64 86,089 42.01 Exercised/Vested (1) (19,969) 20.25 4.42 (125,213) 30.80 6.21 (279,429) 39.20 — — — — Cancelled/Expired — — — (112,706) 45.86 9.43 (25,694) 42.17 (1,739) 54.64 (1,739) 42.01 Outstanding at December 31, 2019 82,310 $ 24.97 $ 5.97 1,934,838 $ 37.11 $ 7.05 389,750 $ 39.67 84,350 $ 54.64 84,350 $ 42.01 Granted — — — 99,872 56.84 9.35 302,591 57.47 84,202 79.18 84,202 56.84 Performance Adjustment (2) — — — — — — — — — — 59,844 42.01 Exercised/Vested (1) (6,875) 25.00 4.49 (98,303) 28.84 5.18 (264,466) 39.89 — — (96,129) 42.01 Cancelled/Expired — — — — — — (11,379) 49.38 — — — — Outstanding at December 31, 2020 75,435 $ 25.00 $ 6.11 1,936,407 $ 38.55 $ 7.26 416,496 $ 52.20 168,552 $ 66.90 132,267 $ 51.45 (1) Represents (i) Class O units which were converted to Class A units, (ii) options to purchase Class A common stock which were exercised, and (iii) the Class A common stock that has been released from restriction and which was not surrendered by the holder to satisfy their statutory minimum federal and state tax obligations associated with the vesting of restricted common stock, with respect to the applicable column. (2) Represents the remeasurement of FFO units issued during the year ended December 31, 2019 based on achievement of certain performance metrics over the performance period.
Summary of assumptions and fair values for restricted stock and options to purchase shares of Class A common stock granted	2020 2019 2018 Fair value of FFO units and restricted stock granted $56.84 - $65.96 $42.01 - $51.25 $34.03 - $54.01 Fair value of TSR units granted $79.18 $54.64 N/A Fair value of options granted $9.35 $7.56 - $8.28 $5.55 - $5.64 Expected term (years) 5.5 5.5 5.5 - 6.0 Expected volatility 27% 28% 28% Expected dividend yield 3.31 % 3.89% - 4.19% 4.82% Expected risk-free interest rates 0.61 % 2.33 % - 2.56 % 2.69 % - 2.73 %
Summary of information about awards outstanding	The following tables summarize information about awards outstanding as of December 31, 2020. Operating Partnership Awards Outstanding Exercise prices Awards outstanding Weight average remaining vesting period Class O Units $ 25.00 75,435 — Total Operating Partnership awards outstanding 75,435 QTS Realty Trust, Inc. Awards Outstanding Exercise prices Awards outstanding Weight average remaining vesting period Restricted stock $ — 416,496 1.0 TSR units — 168,552 0.9 FFO units — 132,267 0.7 Options to purchase Class A common stock $ 21.00 - $56.84 1,936,407 0.9 Total QTS Realty Trust, Inc. awards outstanding 2,653,722
Schedule of quarterly cash dividends	Year Ended December 31, 2020 Record Date Payment Date Per Share Rate Aggregate Dividend/Distribution Amount (in millions) Common Stock September 18, 2020 October 6, 2020 $ 0.47 $ 32.0 June 19, 2020 July 7, 2020 0.47 31.5 March 20, 2020 April 7, 2020 0.47 31.5 December 20, 2019 January 7, 2020 0.44 28.6 $ 123.6 Series A Preferred Stock September 30, 2020 October 15, 2020 $ 0.45 $ 1.9 June 30, 2020 July 15, 2020 0.45 1.9 March 31, 2020 April 15, 2020 0.45 1.9 December 31, 2019 January 15, 2020 0.45 1.9 $ 7.6 Series B Preferred Stock September 30, 2020 October 15, 2020 $ 1.63 $ 5.1 June 30, 2020 July 15, 2020 1.63 5.1 March 31, 2020 April 15, 2020 1.63 5.1 December 31, 2019 January 15, 2020 1.63 5.1 $ 20.4 Year Ended December 31, 2019 Record Date Payment Date Per Share Rate Aggregate Dividend/Distribution Amount (in millions) Common Stock September 19, 2019 October 4, 2019 $ 0.44 $ 27.3 June 25, 2019 July 9, 2019 0.44 27.3 March 20, 2019 April 4, 2019 0.44 27.3 December 21, 2018 January 8, 2019 0.41 23.7 $ 105.6 Series A Preferred Stock September 30, 2019 October 15, 2019 $ 0.45 $ 1.9 June 30, 2019 July 15, 2019 0.45 1.9 March 31, 2019 April 15, 2019 0.45 1.9 December 31, 2018 January 15, 2019 0.45 1.9 $ 7.6 Series B Preferred Stock September 30, 2019 October 15, 2019 $ 1.63 $ 5.1 June 30, 2019 July 15, 2019 1.63 5.1 March 31, 2019 April 15, 2019 1.63 5.1 December 31, 2018 January 15, 2019 1.63 5.1 $ 20.4
Summary of equity issued	The following table represents a summary of our equity issuances of our Class A common stock during the year ended December 31, 2020 (in thousands): Offering Program Forward Net Proceeds Available/(Received) (1) Shares and net proceeds available as of December 31, 2019 3,795 $ 173,776 (2) February 2019 Offering - Settlement (931) (3) (35,841) June 2019 Prior ATM Program - Sales 4,550 243,577 June 2019 Prior ATM Program - Settlements (4,981) (3) (250,496) May 2020 Current ATM Program - Sales 3,128 189,640 June 2020 Offering - Sales 4,400 266,894 Shares and net proceeds available as of December 31, 2020 9,961 $ 587,550 (1) Net Proceeds Available remain subject to certain adjustments until settled. (2) Net Proceeds available reported in the Form 10-K for the period ended December 31, 2019 were $177.8 million. The $4 million decrease is primarily due to QTS’ declared dividends, which reduces cash expected to be received upon full physical settlement of the forward shares. (3) Represents the number of forward shares we elected to physically settle during the year ended December 31, 2020.

Related Party Transactions (Tab

Related Party Transactions (Tables)	12 Months Ended
	Dec. 31, 2020
Related Party Transactions [Abstract]
Summary of related party transactions	The transactions which occurred during the years ended December 31, 2020, 2019 and 2018 are outlined below (in thousands): For the Year Ended December 31, 2020 2019 2018 Tax, utility, insurance and other reimbursement $ 694 $ 967 $ 724 Rent expense 1,027 1,014 1,014 Capital assets acquired — 704 464 Total $ 1,721 $ 2,685 $ 2,202

Earnings per share (Tables)

Earnings per share (Tables)	12 Months Ended
	Dec. 31, 2020
Earnings Per Share [Abstract]
Summary of basic and diluted earnings per share	The computation of basic and diluted net income (loss) per share is as follows (in thousands, except per share data): Year Ended December 31, 2020 2019 2018 Numerator: Net income (loss) $ 14,576 $ 31,665 $ (7,175) (Income) loss attributable to noncontrolling interests 1,330 (374) 2,715 Preferred stock dividends (28,180) (28,180) (16,666) Earnings attributable to participating securities (16,360) (7,828) (947) Net loss available to common stockholders after allocation to participating securities $ (28,634) $ (4,717) $ (22,073) Denominator: Weighted average shares outstanding - basic 60,717 54,837 50,433 Effect of Class O units, TSR units, FFO units and options to purchase Class A common stock on an "as if" converted basis — — — Weighted average shares outstanding - diluted 60,717 54,837 50,433 Basic net loss per share * $ (0.47) $ (0.09) $ (0.44) Diluted net loss per share * $ (0.47) $ (0.09) $ (0.44) * Note: The calculations of basic and diluted net income (loss) per share above do not include the following number of Class A partnership units, Class O units, TSR units, FFO units and options to purchase common stock on an "as if" converted basis, and the effects of Series B Convertible preferred stock on an “as if” converted basis as their respective inclusions would have been antidilutive: Year Ended December 31, 2020 2019 2018 Class A Partnership units 6,648 6,671 6,653 Class O units, TSR units, FFO units and options to purchase common stock on an "as if" converted basis 1,118 518 350 Series B Convertible preferred stock on an "as if" converted basis 6,778 6,729 3,484

Contracts with Customers (Table

Contracts with Customers (Table)	12 Months Ended
	Dec. 31, 2020
Revenue from Contract with Customer [Abstract]
Schedule of future minimum payments to be received under non-cancelable customer contracts	Future minimum payments to be received under non-cancelable customer contracts including both lease rental revenue components and non-lease revenue components that are accounted for as a combined lease component in accordance with ASC Topic 842 which is discussed in Note 2 above (inclusive of payments for contracts which have not yet commenced, and exclusive of variable lease revenue such as recoveries of operating costs from customers) are as follows for the years ending December 31 (in thousands): Year Ended December 31, 2021 $ 435,906 2022 359,860 2023 263,413 2024 214,215 2025 165,002 Thereafter 493,839 Total $ 1,932,235

Quarterly Financial Informati_2

Quarterly Financial Information (Tables)	12 Months Ended
	Dec. 31, 2020
Quarterly Financial Information Disclosure [Abstract]
Summary of selected quarterly information	The tables below reflect the selected quarterly information for the years ended December 31, 2020 and 2019 (in thousands except share data): Three Months Ended December 31, September 30, June 30, March 31, 2020 Revenues $ 143,897 $ 137,538 $ 131,640 $ 126,292 Operating income 17,151 15,016 17,859 15,631 Net income (loss) (10,660) 6,907 10,209 8,120 Net income (loss) attributable to QTS Realty Trust, Inc. (8,922) 6,925 9,892 8,010 Net income (loss) attributable to common stockholders (15,967) (120) 2,847 965 Net loss per share attributable to common shares - basic (0.33) (0.07) (0.05) (0.01) Net loss per share attributable to common shares - diluted (0.33) (0.07) (0.05) (0.01) 2019 Revenues $ 123,707 $ 125,255 $ 119,167 $ 112,689 Operating income 4,218 13,606 14,598 28,734 Net income (loss) (3,606) 6,588 7,535 21,148 Net income (loss) attributable to QTS Realty Trust, Inc. (2,511) 6,637 7,483 19,558 Net income (loss) attributable to common stockholders (9,556) (408) 438 12,513 Net income (loss) per share attributable to common shares - basic (0.20) (0.05) (0.03) 0.20 Net income (loss) per share attributable to common shares - diluted (0.20) (0.05) (0.03) 0.20

Description of Business (Detail

Description of Business (Details)	12 Months Ended
	Dec. 31, 2020property
Organization And Description Of Business [Line Items]
Number of properties	28
QualityTech LP
Organization And Description Of Business [Line Items]
Ownership interest	90.80%

Summary of Significant Accoun_4

Summary of Significant Accounting Policies (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Summary Of Significant Accounting Policies [Line Items]
Maximum exposure to losses	$ 22,600
Useful life of property	40 years
Depreciation expense from operation	$ 161,200	$ 130,800	$ 113,500
Real estate cost capitalized excluding interest cost	18,400	17,800	17,400
Real estate interest cost capitalized incurred	30,200	33,200	26,800
(Gain) loss on sale of real estate, net	0	14,769	0
Gain (loss) on disposition of property	$ 0	14,769	(6,994)
Term Loan Maturing 2025
Summary Of Significant Accounting Policies [Line Items]
Interest rate	4.75%
Senior Notes 4.75 Due 2025
Summary Of Significant Accounting Policies [Line Items]
Interest rate	3.875%
Real Estate Assets
Summary Of Significant Accounting Policies [Line Items]
Depreciation expense from operation	$ 147,800	118,900	101,200
Non-Real Estate Assets
Summary Of Significant Accounting Policies [Line Items]
Depreciation expense from operation	$ 13,400	11,900	12,300
Minimum | Real Property
Summary Of Significant Accounting Policies [Line Items]
Useful life of property	20 years
Maximum | Real Property
Summary Of Significant Accounting Policies [Line Items]
Useful life of property	40 years
Maximum | Leasehold Improvements
Summary Of Significant Accounting Policies [Line Items]
Useful life of property	20 years
Restructuring Charges
Summary Of Significant Accounting Policies [Line Items]
Gain (loss) on disposition of property			$ 7,000
Atlanta Metro facility
Summary Of Significant Accounting Policies [Line Items]
(Gain) loss on sale of real estate, net		1,400
Owned Properties | Manassas, Virginia
Summary Of Significant Accounting Policies [Line Items]
(Gain) loss on sale of real estate, net		13,400
Transaction cost		$ 5,800

Summary of Significant Accoun_5

Summary of Significant Accounting Policies (Additional Information 1) (Details)	1 Months Ended	12 Months Ended
	Oct. 31, 2019	Dec. 31, 2020USD ($)item	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Summary Of Significant Accounting Policies [Line Items]
Impairment losses		$ 0
Number of reporting units | item		1
Amortization of the deferred financing costs		$ 4,053,000	$ 3,877,000	$ 3,856,000
Write off of deferred loan costs		3,784,000	1,532,000	605,000
Amortization of deferred leasing costs		26,100,000	24,200,000	21,300,000
Aggregate allowance for doubtful accounts		5,400,000	2,300,000
Deferred income		85,351,000	39,169,000	33,200,000
Amortization of deferred revenue		20,300,000	15,200,000	12,500,000
Equity based compensation associated with the acceleration of equity awards		1,800,000		3,100,000
Unsecured Revolving Credit Facility
Summary Of Significant Accounting Policies [Line Items]
Amortization of the deferred financing costs		4,100,000	3,900,000	3,900,000
Write off of deferred loan costs				600,000
Term Loan Maturing 2025
Summary Of Significant Accounting Policies [Line Items]
Aggregate principal amount		$ 400,000,000
Interest rate		4.75%
Write off of deferred loan costs		$ 3,700,000
Revolving Credit Facility Maturing December 17 2023 | Unsecured Credit Facility Two
Summary Of Significant Accounting Policies [Line Items]
Loan term	7 years
Transaction Integration and Impairment Costs
Summary Of Significant Accounting Policies [Line Items]
Impairment losses			11,500,000
Restructuring Charges
Summary Of Significant Accounting Policies [Line Items]
Impairment losses				8,800,000
Company recorded equity-based compensation expense net of repurchased awards and forfeits		27,000,000	16,400,000	$ 18,100,000
Rents and Other Receivables
Summary Of Significant Accounting Policies [Line Items]
Amount of the straight-line rent receivable on the balance sheets included in rents and other receivables, net		$ 63,600,000	$ 38,700,000

Summary of Significant Accoun_6

Summary of Significant Accounting Policies (Deferred Financing Costs, Net of Accumulated Amortization) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Deferred financing costs	$ 13,786	$ 13,776
Accumulated amortization	(7,752)	(5,743)
Deferred financing costs, net	6,034	8,033
Fixed debt arrangements
Deferred financing costs	19,327	15,777
Accumulated amortization	(4,765)	(4,937)
Deferred financing costs, net	$ 14,562	$ 10,840

Summary of Significant Accoun_7

Summary of Significant Accounting Policies (Deferred Leasing Costs, Net of Accumulated Amortization) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Accounting Policies [Abstract]
Deferred leasing costs	$ 101,480	$ 77,178
Accumulated amortization	(43,825)	(32,848)
Deferred leasing costs, net	$ 57,655	$ 44,330

Summary of Significant Accoun_8

Summary of Significant Accounting Policies (Additional Information 2) (Details)	12 Months Ended
	Dec. 31, 2020segmentcustomer
Summary Of Significant Accounting Policies [Line Items]
Number of operating segments | segment	1
Number of reportable segments | segment	1
Minimum quarterly distribution of available cash	100.00%
Customer One | Rental Revenue
Summary Of Significant Accounting Policies [Line Items]
Number of customers	1
Percentage of total revenue	11.80%
Customer One | Accounts Receivable
Summary Of Significant Accounting Policies [Line Items]
Number of customers	1
Percentage of total revenue	39.20%
Percentage of trade accounts receivable	10.00%
Two Customers | Accounts Receivable
Summary Of Significant Accounting Policies [Line Items]
Number of customers	2
Percentage of trade accounts receivable	45.00%
Two Customers | Accounts Receivable | Minimum
Summary Of Significant Accounting Policies [Line Items]
Percentage of trade accounts receivable	5.00%

Summary of Significant Accoun_9

Summary of Significant Accounting Policies (Recently Adopted Accounting Standards) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2020
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease right-of-use assets, net	$ 57,141	$ 51,342
Operating lease liabilities	$ 64,416	$ 58,005
Accounting Standards Update [Extensible List]	us-gaap:AccountingStandardsUpdate201602Member

Summary of Significant Accou_10

Summary of Significant Accounting Policies Summary of Significant Account Policies - Other Revenue (Details)	12 Months Ended
	Dec. 31, 2020
Cloud and managed services
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, performance obligation, description of timing	These contracts generally have a remaining term ranging from month-to-month to three years.

Acquisitions and Sales (Land Pa

Acquisitions and Sales (Land Parcels) (Details) $ in Millions	1 Months Ended	12 Months Ended
	Nov. 30, 2019USD ($)	Dec. 31, 2020USD ($)a	Dec. 31, 2019USD ($)a
Construction in Progress
Property, Plant and Equipment [Line Items]
Acres of land | a		126	107
Payments to acquire land		$ 43.9	$ 31.6
Atlanta Building Sale
Property, Plant and Equipment [Line Items]
Gain on sale of property	$ 1.4
Lease term of facility with global cloud-based software company		20 years

Acquisitions and Sales (Narrati

Acquisitions and Sales (Narrative) (Details) $ in Millions	Apr. 23, 2019USD ($)ft²itemMW
Business Combinations [Abstract]
Number of data centers acquired | item	2
Acquisition cash consideration | $	$ 44.5
Floor capacity (in square feet) | ft²	160,000
Gross power capacity (in megawatt) | MW	30

Acquisitions and Sales (Allocat

Acquisitions and Sales (Allocation of the Fair Value of Assets Acquired and Liabilities Assumed as of the Acquisition Date) (Details) - USD ($) $ in Thousands	Apr. 23, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Business Combinations [Abstract]
Land	$ 1,743	$ 0	$ 1,743	$ 0
Buildings and improvements	8,640	0	8,640	445
Construction in progress	29,902	43,933	61,514	114,283
Acquired intangibles (In-place lease & above market lease)	2,911
Deferred costs	906
Other assets	128	$ 0	$ 128	$ 0
Net Working Capital	554
Total identifiable assets acquired	44,784
Acquired below market lease	284
Total liabilities assumed	284
Net identifiable assets acquired	$ 44,500
Buildings and improvements weighted avg remaining useful life (in years)	24 years
Acquired intangibles weighted avg remaining useful life (in years)	3 years
Deferred costs weighted avg remaining useful life (in years)	3 years
Other assets weighted avg remaining useful life (in years)	3 years
Acquired below market lease weighted avg remaining useful life (in years)	3 years

Acquired Intangibles Assets a_2

Acquired Intangibles Assets and Liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Finite-lived intangible assets
Gross Carrying Value	$ 149,335	$ 149,075
Accumulated Amortization	(81,245)	(67,396)
Total	68,090	81,679
Acquired Intangible Liabilities
Acquired intangible liabilities	17,317	17,292
Accumulated Amortization	(7,568)	(6,398)
New Carrying Value	$ 9,749	10,894
Customer Relationships
Finite-lived intangible assets
Useful Lives	12 years
Gross Carrying Value	$ 95,705	95,705
Accumulated Amortization	(44,361)	(36,411)
Total	51,344	59,294
In Place Leases
Finite-lived intangible assets
Gross Carrying Value	34,813	34,588
Accumulated Amortization	(26,812)	(22,522)
Total	$ 8,001	12,066
In Place Leases | Minimum
Finite-lived intangible assets
Useful Lives	6 months
In Place Leases | Maximum
Finite-lived intangible assets
Useful Lives	10 years
Solar Power Agreement
Finite-lived intangible assets
Useful Lives	17 years
Gross Carrying Value	$ 13,747	13,747
Accumulated Amortization	(5,256)	(4,448)
Total	8,491	9,299
Above Market Leases As Lessor
Acquired above market leases - as Lessee
Gross Carrying Value	5,070	5,035
Accumulated Amortization	(4,816)	(4,015)
Net Carrying Value	$ 254	1,020
Above Market Leases As Lessor | Minimum
Finite-lived intangible assets
Useful Lives	6 months
Above Market Leases As Lessor | Maximum
Finite-lived intangible assets
Useful Lives	8 years
Below Market Leases As Lessor
Acquired below market leases - as Lessor
Gross Carrying Value	$ 1,117	1,092
Accumulated Amortization	(1,113)	(967)
Net Carrying Value	$ 4	125
Below Market Leases As Lessor | Minimum
Finite-lived intangible assets
Useful Lives	2 years
Below Market Leases As Lessor | Maximum
Finite-lived intangible assets
Useful Lives	4 years
Above Market Lease As Lessee
Acquired above market leases - as Lessee
Gross Carrying Value	$ 2,453	2,453
Accumulated Amortization	(1,199)	(983)
Net Carrying Value	$ 1,254	$ 1,470
Above Market Lease As Lessee | Minimum
Finite-lived intangible assets
Useful Lives	11 years
Above Market Lease As Lessee | Maximum
Finite-lived intangible assets
Useful Lives	12 years

Acquired Intangibles Assets a_3

Acquired Intangibles Assets and Liabilities - Amortization (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Finite-Lived Intangible Assets [Line Items]
Amortization of acquired above and below-market leases, net	$ 429	$ 187	$ 465
Amortization of all other identified intangible assets	12,600	13,200	$ 15,000
Estimated amortization of all other identified intangible assets
Total	68,090	$ 81,679
Acquired favorable and unfavorable leases
Estimated amortization of acquired favorable and unfavorable leases Rental Revenue
2021	164
2022	55
2023	25
2024	6
2025	0
Total	250
Estimated amortization of acquired favorable and unfavorable leases Rental Expense
2021	(216)
2022	(216)
2023	(216)
2024	(216)
2025	(216)
Thereafter	(174)
Total	(1,254)
All other identified intangible assets
Estimated amortization of all other identified intangible assets
2021	10,634
2022	10,088
2023	10,084
2024	8,967
2025	7,978
Thereafter	11,594
Total	$ 59,345

Real Estate Assets and Constr_3

Real Estate Assets and Construction in Progress (Summary of Owned or Leased Properties by the Company) (Details) $ in Thousands	Dec. 31, 2020USD ($)property	Dec. 31, 2019USD ($)property
Real Estate Properties [Line Items]
Land	$ 165,109	$ 130,605
Buildings, Improvements and Equipment	2,839,261	2,178,901
Construction in progress	1,028,765	920,922
Total cost	4,033,135	3,230,428
Owned Properties | Atlanta, Georgia Campus
Real Estate Properties [Line Items]
Land	55,157	44,588
Buildings, Improvements and Equipment	700,142	525,300
Construction in progress	191,072	128,930
Total cost	946,371	698,818
Owned Properties | Ashburn, Virginia Campus
Real Estate Properties [Line Items]
Land	16,476	16,476
Buildings, Improvements and Equipment	371,725	156,396
Construction in progress	185,903	189,375
Total cost	574,104	362,247
Owned Properties | Irving, Texas
Real Estate Properties [Line Items]
Land	8,606	8,606
Buildings, Improvements and Equipment	392,275	369,727
Construction in progress	99,591	98,170
Total cost	500,472	476,503
Owned Properties | Chicago, Illinois
Real Estate Properties [Line Items]
Land	9,400	9,400
Buildings, Improvements and Equipment	250,336	205,026
Construction in progress	104,117	86,878
Total cost	363,853	301,304
Owned Properties | Richmond, Virginia
Real Estate Properties [Line Items]
Land	2,180	2,180
Buildings, Improvements and Equipment	233,927	195,684
Construction in progress	120,577	139,948
Total cost	356,684	337,812
Owned Properties | Suwanee, Georgia (Atlanta-Suwanee)
Real Estate Properties [Line Items]
Land	3,521	3,521
Buildings, Improvements and Equipment	184,467	174,124
Construction in progress	6,718	5,559
Total cost	194,706	183,204
Owned Properties | Piscataway, New Jersey
Real Estate Properties [Line Items]
Land	7,466	7,466
Buildings, Improvements and Equipment	122,176	103,553
Construction in progress	30,401	36,056
Total cost	160,043	147,075
Owned Properties | Fort Worth, Texas
Real Estate Properties [Line Items]
Land	9,079	9,079
Buildings, Improvements and Equipment	124,054	55,018
Construction in progress	1,064	35,722
Total cost	134,197	99,819
Owned Properties | Hillsboro, Oregon
Real Estate Properties [Line Items]
Land	18,414	0
Buildings, Improvements and Equipment	34,594	0
Construction in progress	78,390	63,573
Total cost	131,398	63,573
Owned Properties | Santa Clara, California
Real Estate Properties [Line Items]
Land	0	0
Buildings, Improvements and Equipment	117,343	114,499
Construction in progress	9,385	1,238
Total cost	126,728	115,737
Owned Properties | Eemshaven, Netherlands
Real Estate Properties [Line Items]
Land	5,366	0
Buildings, Improvements and Equipment	21,712	0
Construction in progress	47,531	37,267
Total cost	74,609	37,267
Owned Properties | Sacramento, California
Real Estate Properties [Line Items]
Land	1,481	1,481
Buildings, Improvements and Equipment	66,300	65,258
Construction in progress	12	163
Total cost	67,793	66,902
Owned Properties | Manassas, Virginia
Real Estate Properties [Line Items]
Land	0	0
Buildings, Improvements and Equipment	25	0
Construction in progress	67,073	57,662
Total cost	67,098	57,662
Owned Properties | Dulles, Virginia
Real Estate Properties [Line Items]
Land	3,154	3,154
Buildings, Improvements and Equipment	54,323	48,651
Construction in progress	4,148	4,688
Total cost	61,625	56,493
Owned Properties | Princeton, New Jersey
Real Estate Properties [Line Items]
Land	20,700	20,700
Buildings, Improvements and Equipment	35,261	35,192
Construction in progress	5	39
Total cost	55,966	55,931
Owned Properties | Phoenix, Arizona
Real Estate Properties [Line Items]
Land	0	0
Buildings, Improvements and Equipment	0	0
Construction in progress	37,729	31,265
Total cost	37,729	31,265
Owned Properties | Groningen, Netherlands
Real Estate Properties [Line Items]
Land	1,896	1,741
Buildings, Improvements and Equipment	11,206	9,085
Construction in progress	3,730	3,028
Total cost	16,832	13,854
Owned Properties | Other
Real Estate Properties [Line Items]
Land	2,213	2,213
Buildings, Improvements and Equipment	36,636	36,163
Construction in progress	41,094	120
Total cost	79,943	38,496
Leased Properties
Real Estate Properties [Line Items]
Land	0	0
Buildings, Improvements and Equipment	82,759	85,225
Construction in progress	225	1,241
Total cost	$ 82,984	$ 86,466
Number of facilities leased | property	7	7

Leases - Finance leases (Detail

Leases - Finance leases (Details)	12 Months Ended
	Dec. 31, 2020item
Operating leases:
Number of finance leases	1
Minimum
Operating leases:
Finance lease, remaining lease term	1 year
Maximum
Operating leases:
Finance lease, remaining lease term	17 years

Leases - Operating leases (Deta

Leases - Operating leases (Details)	12 Months Ended
	Dec. 31, 2020itemproperty
Operating leases:
Number of operating leases | property	6
Number of ground leases under operating leases | item	1
Minimum
Operating leases:
Operating lease, remaining term	3 years
Maximum
Operating leases:
Operating lease, remaining term	6 years

Leases - Components of lease ex

Leases - Components of lease expenses (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Finance lease cost:
Amortization of assets	$ 4,150	$ 3,535
Interest on lease liabilities	1,915	1,693
Operating lease expense:
Operating lease cost	9,012	9,102
Variable lease cost	1,072	1,109
Sublease income	(193)	(187)
Total lease costs	$ 15,956	$ 15,252

Leases - Supplemental balance s

Leases - Supplemental balance sheet information (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Operating leases:
Operating lease right-of-use assets	$ 51,342	$ 57,141
Operating lease liabilities	58,005	64,416
Finance leases:
Property and equipment, at cost	4,033,135	3,230,428
Accumulated amortization	(702,944)	(558,560)
Real Estate Assets, net	3,330,191	2,671,868
Finance lease liabilities	41,718	45,141
Finance leased assets
Operating leases:
Operating lease right-of-use assets	51,342	57,141
Operating lease liabilities	58,005	64,416
Finance leases:
Property and equipment, at cost	49,554	50,437
Accumulated amortization	(8,864)	(4,830)
Real Estate Assets, net	$ 40,690	$ 45,607

Leases - Other information (Det

Leases - Other information (Details)	Dec. 31, 2020	Dec. 31, 2019
Leases [Abstract]
Operating leases - Weighted average remaining lease term (in years)	13 years 4 months 24 days	13 years 8 months 12 days
Finance leases - Weighted average remaining lease term (in years)	10 years 3 months 18 days	11 years 4 months 24 days
Operating leases - Weighted average discount rate	5.20%	5.10%
Finance leases - Weighted average discount rate	4.30%	4.30%

Leases - Supplemental cash flow

Leases - Supplemental cash flow and other information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Leases [Abstract]
Operating cash flows for operating leases	$ 12,048	$ 9,834
Operating cash flows for finance leases	1,914	1,704
Financing cash flows for finance leases	$ 2,579	$ 2,855	$ 7,626

Leases - Maturities of lease li

Leases - Maturities of lease liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Operating Leases Maturities:
2021	$ 9,818
2022	10,266
2023	10,393
2024	8,317
2025	8,036
Thereafter	40,872
Total Lease Payments	87,702
Less: Imputed Interest	29,697
Total Lease Obligations	58,005	$ 64,416
Finance Leases Maturities:
2021	4,446
2022	4,570
2023	4,707
2024	4,847
2025	4,992
Thereafter	28,902
Total Lease Payments	52,464
Less: Imputed Interest	10,746
Total Lease Obligations	$ 41,718	$ 45,141

Leases - Leases as lessor (Deta

Leases - Leases as lessor (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Lease revenue:
Minimum lease revenue	$ 464,005	$ 409,157	$ 367,388
Variable lease revenue (primarily recoveries from customers)	55,853	55,966	46,232
Total lease revenue	$ 519,858	$ 465,123	$ 413,620

Investments in Unconsolidated_2

Investments in Unconsolidated Entity (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Investments in Unconsolidated Joint Ventures
Assets	$ 3,898,572	$ 3,223,533
Debt outstanding	1,842,337
Equity Method Investment, Nonconsolidated Investee or Group of Investees
Investments in Unconsolidated Joint Ventures
Assets	141,500	127,800
Debt outstanding	$ 90,100	68,200
Joint venture with Alinda
Investments in Unconsolidated Joint Ventures
Lease term of facility with global cloud-based software company	10 years
Equity method investments	$ 22,600	$ 30,200
Ownership interest (as a percent)	50.00%

Debt (Outstanding Debt Includin

Debt (Outstanding Debt Including Capital Leases) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Oct. 07, 2020	Dec. 31, 2019	Nov. 08, 2017	Mar. 08, 2017
Debt Instrument [Line Items]
Weighted average coupon interest rate	2.85%
Total debt and lease obligations	$ 1,884,055		$ 1,463,904
Less net debt issuance costs	(14,562)		(10,839)
Total outstanding debt, net	$ 1,869,493		1,453,065
Lenexa Mortgage
Debt Instrument [Line Items]
Interest rate					4.10%
Unsecured Revolving Credit Facility | Unsecured Revolving Credit Facility
Debt Instrument [Line Items]
Weighted average coupon interest rate	1.41%
Outstanding debt	$ 392,337		317,028
Term Loan A | Term Loan A
Debt Instrument [Line Items]
Weighted average coupon interest rate	3.26%
Outstanding debt	$ 225,000		225,000
Term Loan B | Term Loan B
Debt Instrument [Line Items]
Weighted average coupon interest rate	3.30%
Outstanding debt	$ 225,000		225,000
Term Loan C | Term Loan C
Debt Instrument [Line Items]
Weighted average coupon interest rate	3.46%
Outstanding debt	$ 250,000		250,000
Term Loan D
Debt Instrument [Line Items]
Weighted average coupon interest rate	1.45%
Outstanding debt	$ 250,000		0
4.750% Senior Notes
Debt Instrument [Line Items]
Weighted average coupon interest rate	4.75%
Outstanding debt	$ 0		400,000
4.750% Senior Notes | Senior Notes
Debt Instrument [Line Items]
Interest rate	4.75%			4.75%
3.875% Senior Notes
Debt Instrument [Line Items]
Weighted average coupon interest rate	3.88%
Outstanding debt	$ 500,000		0
Lenexa Mortgage | Lenexa Mortgage
Debt Instrument [Line Items]
Weighted average coupon interest rate	4.10%
Outstanding debt	$ 0		1,736
Finance Leases | Finance Leases
Debt Instrument [Line Items]
Weighted average coupon interest rate	4.33%
Outstanding debt	$ 41,718		$ 45,140
Senior Notes due 2028
Debt Instrument [Line Items]
Interest rate	3.875%	3.875%

Debt (Unsecured Credit Facility

Debt (Unsecured Credit Facility Narrative) (Details) - USD ($)	1 Months Ended	12 Months Ended
	Oct. 31, 2019	Dec. 31, 2020	Oct. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Debt issuance costs, net		$ 6,034,000		$ 8,033,000
Weighted average interest rate		2.85%
Unsecured Credit Facility
Debt Instrument [Line Items]
Credit facility maximum borrowing capacity			$ 1,950,000,000
Outstanding debt		$ 1,100,000,000
Weighted average interest rate		2.65%
Term Loan
Debt Instrument [Line Items]
Outstanding debt		$ 700,000,000
Unsecured Credit Facility Two
Debt Instrument [Line Items]
Debt extension period	1 year
Unsecured Credit Facility Two | Term Loan
Debt Instrument [Line Items]
Debt issuance costs, net		7,100,000
Unsecured Credit Facility Two | Term Loan A Maturing December 17 2024
Debt Instrument [Line Items]
Credit facility maximum borrowing capacity	$ 225,000,000
Unsecured Credit Facility Two | Term Loan B Maturing April 27 2025
Debt Instrument [Line Items]
Credit facility maximum borrowing capacity	225,000,000
Unsecured Credit Facility Two | Term Loan C Maturing October 18 2026
Debt Instrument [Line Items]
Credit facility maximum borrowing capacity	250,000,000
Unsecured Credit Facility Two | Unsecured Revolving Credit Facility
Debt Instrument [Line Items]
Outstanding debt		392,300,000
Unsecured Credit Facility Two | Revolving Credit Facility Maturing December 17 2023
Debt Instrument [Line Items]
Credit facility maximum borrowing capacity	1,000,000,000				$ 1,700,000,000
Additional contingent borrowing capacity, maximum					$ 2,200,000,000
Unsecured Credit Facility Two | Various Foreign Currency
Debt Instrument [Line Items]
Credit facility maximum borrowing capacity	$ 300,000,000
Unsecured Credit Facility Two | Letter of Credit
Debt Instrument [Line Items]
Letter of credit outstanding		$ 3,500,000
Unsecured Credit Facility Two | Minimum | Term Loan C Maturing October 18 2026 | LIBOR
Debt Instrument [Line Items]
Debt instrument spread on variable interest rate	1.50%
Unsecured Credit Facility Two | Minimum | Term Loan C Maturing October 18 2026 | Base Rate
Debt Instrument [Line Items]
Debt instrument spread on variable interest rate	0.50%
Unsecured Credit Facility Two | Minimum | Term Loan A and Term Loan B | LIBOR
Debt Instrument [Line Items]
Debt instrument spread on variable interest rate		1.20%
Unsecured Credit Facility Two | Minimum | Term Loan A and Term Loan B | Base Rate
Debt Instrument [Line Items]
Debt instrument spread on variable interest rate		0.20%
Unsecured Credit Facility Two | Minimum | Revolving Credit Facility Maturing December 17 2023 | LIBOR
Debt Instrument [Line Items]
Debt instrument spread on variable interest rate		1.25%
Unsecured Credit Facility Two | Minimum | Revolving Credit Facility Maturing December 17 2023 | Base Rate
Debt Instrument [Line Items]
Debt instrument spread on variable interest rate		0.25%
Unsecured Credit Facility Two | Maximum | Term Loan C Maturing October 18 2026 | LIBOR
Debt Instrument [Line Items]
Debt instrument spread on variable interest rate	1.85%
Unsecured Credit Facility Two | Maximum | Term Loan C Maturing October 18 2026 | Base Rate
Debt Instrument [Line Items]
Debt instrument spread on variable interest rate	0.85%
Unsecured Credit Facility Two | Maximum | Term Loan A and Term Loan B | LIBOR
Debt Instrument [Line Items]
Debt instrument spread on variable interest rate		1.80%
Unsecured Credit Facility Two | Maximum | Term Loan A and Term Loan B | Base Rate
Debt Instrument [Line Items]
Debt instrument spread on variable interest rate		0.80%
Unsecured Credit Facility Two | Maximum | Revolving Credit Facility Maturing December 17 2023 | LIBOR
Debt Instrument [Line Items]
Debt instrument spread on variable interest rate		1.85%
Unsecured Credit Facility Two | Maximum | Revolving Credit Facility Maturing December 17 2023 | Base Rate
Debt Instrument [Line Items]
Debt instrument spread on variable interest rate		0.85%

Debt (Senior Notes and Mortgage

Debt (Senior Notes and Mortgage Notes Payable) (Details) - USD ($)	Mar. 08, 2017	Nov. 30, 2020	Oct. 31, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Oct. 07, 2020	Nov. 08, 2017
Debt Instrument [Line Items]
Debt restructuring costs				$ 18,036,000	$ 1,523,000	$ 605,000
Deferred finance costs, net				$ 6,034,000	$ 8,033,000
Lenexa Mortgage
Debt Instrument [Line Items]
Aggregate principal amount	$ 1,900,000
Interest rate	4.10%
Periodic payment	$ 1,600,000
Extinguishment of debt		$ 1,700,000
Term Loan D
Debt Instrument [Line Items]
Current borrowing capacity			$ 250,000,000
Credit facility maximum borrowing capacity			500,000,000
Accordion feature			$ 250,000,000
Term Loan D | LIBOR
Debt Instrument [Line Items]
Floor over LIBOR			0.25%
Term Loan D | LIBOR | Minimum
Debt Instrument [Line Items]
Debt instrument spread on variable interest rate			1.20%
Term Loan D | LIBOR | Maximum
Debt Instrument [Line Items]
Debt instrument spread on variable interest rate			1.80%
Term Loan D | Base Rate | Minimum
Debt Instrument [Line Items]
Debt instrument spread on variable interest rate			0.20%
Term Loan D | Base Rate | Maximum
Debt Instrument [Line Items]
Debt instrument spread on variable interest rate			0.80%
Unsecured Credit Facility
Debt Instrument [Line Items]
Current borrowing capacity			$ 1,700,000,000
Credit facility maximum borrowing capacity			$ 1,950,000,000
Operating Partnership and QTS Finance Corporation | Senior Notes
Debt Instrument [Line Items]
Aggregate principal amount								$ 400,000,000
Interest rate				4.75%				4.75%
Percentage of issued price equal to face value								100.00%
Debt restructuring costs				$ 18,000,000
Operating Partnership and QTS Finance Corporation | Senior Notes | Early Redemption Fees
Debt Instrument [Line Items]
Debt restructuring costs				14,300,000
Operating Partnership and QTS Finance Corporation | Senior Notes | Non-cash Charge
Debt Instrument [Line Items]
Debt restructuring costs				$ 3,700,000
5.875% Senior Notes due 2022 | Senior Notes
Debt Instrument [Line Items]
Interest rate								5.875%
Senior Notes due 2028
Debt Instrument [Line Items]
Aggregate principal amount							$ 500,000,000
Interest rate				3.875%			3.875%
Percentage of issued price equal to face value							100.00%
Senior Notes due 2028 | Senior Notes
Debt Instrument [Line Items]
Deferred finance costs, net				$ 7,500,000

Debt (Annual Remaining Principa

Debt (Annual Remaining Principal Payment) (Details) $ in Thousands	Dec. 31, 2020USD ($)
Debt Disclosure [Abstract]
2021	$ 0
2022	0
2023	392,337
2024	225,000
2025	225,000
Thereafter	1,000,000
Total	$ 1,842,337

Income Taxes - Components of In

Income Taxes - Components of Income tax Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Current:
U.S. federal	$ 0	$ 0	$ (50)
U.S. State	368	298	395
Outside United States	7	13	78
Total Current	375	311	423
Deferred:
U.S. federal	71	(276)	(3,727)
U.S. State	(66)	(71)	(64)
Outside United States	58	(1)	0
Total Deferred	63	(348)	(3,791)
Total	$ 438	$ (37)	$ (3,368)

Income Taxes - Temporary Differ

Income Taxes - Temporary Differences and Carry Forwards Which Give Rise to Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Deferred tax assets
Net operating loss carryforwards	$ 22,950	$ 20,218	$ 17,610
Deferred revenue and setup charges	1,062	1,299	3,171
Operating lease liabilities	1,904	2,266	0
Property and equipment	0	512	0
Leases	400	0	1
Credits	300	300	287
Equity compensation	1,654	1,119	952
Bad debt reserve	191	18	409
Intangibles	1,038	804	0
Interest expense carryforward IRC Sec. 163(j)	1,164	2,782	2,253
Other	857	257	582
Gross deferred tax assets	31,520	29,575	25,265
Deferred tax liabilities
Property and equipment	(616)	0	(3,089)
Goodwill	(3,042)	(2,494)	(1,953)
Intangibles	0	(591)	(11,910)
Operating lease right-of-use assets	(1,056)	(1,261)	0
Prepaid commissions	(774)	(1,007)	(956)
Other	(218)	(224)	(93)
Gross deferred tax liabilities	(5,706)	(5,577)	(18,001)
Net deferred tax asset	25,814	23,998	7,264
Valuation allowance	26,624	24,747	8,361
Net deferred tax liability	$ (810)	$ (749)	$ (1,097)

Income Taxes - Schedule of Diff

Income Taxes - Schedule of Differences between Total Income Tax or Benefit and Amount Computed by Applying the Statutory Income Tax Rate (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Statutory rate applied to pre-tax loss	$ (1,380)	$ (12,991)	$ (9,656)
Permanent differences, net	248	16	97
State income tax, net of federal benefit	(421)	(2,868)	(1,430)
Foreign income tax	7	13	78
Federal and State rate change	(1)	(20)	(146)
Other	109	(110)	41
Valuation allowance increase	1,876	15,923	7,648
Total tax expense (benefit)	$ 438	$ (37)	$ (3,368)
Effective tax rate	(6.70%)	0.10%	7.30%

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2020USD ($)entity	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Number of subsidiaries taxed as taxable REIT | entity	2
Net operating loss carry forwards related to federal income taxes	$ 33,400
Net operating loss carryforwards no expiration period	42,300
Net operating loss carryforwards related to State income taxes	86,000
Interest expense carryforward with no expiration	4,500
Unrecognized tax benefits	0	$ 0	$ 0
Interest and penalties related to income taxes	0	0	0
Valuation allowance	26,624	$ 24,747	$ 8,361
Deferred tax assets valuation allowance change	$ 1,900
Federal | Maximum
Net operating loss carry forwards, expiration period	16 years
Federal | Minimum
Net operating loss carry forwards, expiration period	11 years
State | Maximum
Net operating loss carry forwards, expiration period	20 years
State | Minimum
Net operating loss carry forwards, expiration period	1 year

Derivative Instruments - Narrat

Derivative Instruments - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Derivative [Line Items]
Increase/decrease in interest expense	$ (10,100,000)	$ 1,000,000	$ (100,000)
Cash flow hedge gain (loss) to be reclassified within twelve months	13,500,000
Interest Rate Swap
Derivative [Line Items]
Derivative instruments, notional amount	700,000,000
Ineffectiveness recognized	0	0	$ 0
Interest Rate Swap | Term Loan
Derivative [Line Items]
Aggregate principal amount	700,000,000
Interest Rate Swap | Term Loan A Maturing December 17 2024
Derivative [Line Items]
Aggregate principal amount	225,000,000
Interest Rate Swap | Term Loan B Maturing April 27 2025
Derivative [Line Items]
Aggregate principal amount	225,000,000
Interest Rate Swap | Term Loan C Maturing October 18 2026
Derivative [Line Items]
Aggregate principal amount	250,000,000
Interest Rate Swap | Cash flow hedging
Derivative [Line Items]
Derivative liability, fair value	$ (49,800,000)	$ (19,900,000)

Derivative Instruments - Intere

Derivative Instruments - Interest rate derivatives and their fair values (Details) - USD ($)	Dec. 31, 2020	Dec. 31, 2019
Interest Rate Swap
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional amount of derivative	$ 700,000,000
Interest Rate Swap | Cash flow hedging
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Fair Value	(49,796,000)	$ (19,916,000)
Swap instrument one matures on December 17, 2021 | Cash flow hedging
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional amount of derivative	$ 25,000,000	25,000,000
Fixed Rate Per annum	1.989%
Fair Value	$ (447,000)	(209,000)
Swap instrument two matures on December 17, 2021 | Cash flow hedging
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional amount of derivative	$ 100,000,000	100,000,000
Fixed Rate Per annum	1.989%
Fair Value	$ (1,788,000)	(837,000)
Swap instrument three matures on December 17, 2021 | Cash flow hedging
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional amount of derivative	$ 75,000,000	75,000,000
Fixed Rate Per annum	1.989%
Fair Value	$ (1,342,000)	(627,000)
Swap instrument one matures on April 27, 2022 | Cash flow hedging
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional amount of derivative	$ 50,000,000	50,000,000
Fixed Rate Per annum	2.033%
Fair Value	$ (1,248,000)	(545,000)
Swap instrument two matures on April 27, 2022 | Cash flow hedging
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional amount of derivative	$ 100,000,000	100,000,000
Fixed Rate Per annum	2.029%
Fair Value	$ (2,490,000)	(1,081,000)
Swap instrument three matures on April 27, 2022 | Cash flow hedging
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional amount of derivative	$ 50,000,000	50,000,000
Fixed Rate Per annum	2.033%
Fair Value	$ (1,248,000)	(545,000)
Swap instrument one matures on December 17, 2023 | Cash flow hedging
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional amount of derivative	$ 100,000,000	100,000,000
Fixed Rate Per annum	2.617%
Fair Value	$ (7,191,000)	(4,007,000)
Swap instrument one matures on April 27, 2024 | Cash flow hedging
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional amount of derivative	$ 100,000,000	100,000,000
Fixed Rate Per annum	2.621%
Fair Value	$ (8,000,000)	(4,324,000)
Swap instrument one maturing October 18, 2026 | Cash flow hedging
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional amount of derivative	$ 70,000,000	0
Fixed Rate Per annum	0.968%
Fair Value	$ (2,174,000)	0
Swap instrument two maturing October18, 2026 | Cash flow hedging
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional amount of derivative	$ 30,000,000	0
Fixed Rate Per annum	0.973%
Fair Value	$ (938,000)	0
Swap instrument two matures on December 17, 2023 | Cash flow hedging
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional amount of derivative	$ 200,000,000	200,000,000
Fixed Rate Per annum	2.636%
Fair Value	$ (9,648,000)	(3,939,000)
Swap instrument two matures on April 27, 2024 | Cash flow hedging
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional amount of derivative	$ 200,000,000	200,000,000
Fixed Rate Per annum	2.642%
Fair Value	$ (9,500,000)	(3,802,000)
Swap instrument one maturing December 17, 2024 | Cash flow hedging
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional amount of derivative	$ 125,000,000	0
Fixed Rate Per annum	1.014%
Fair Value	$ (704,000)	0
Swap instrument two maturing December 17, 2024 | Cash flow hedging
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional amount of derivative	$ 100,000,000	0
Fixed Rate Per annum	1.035%
Fair Value	$ (584,000)	0
Swap instrument three maturing October 18, 2026 | Cash flow hedging
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional amount of derivative	$ 75,000,000	0
Fixed Rate Per annum	1.11%
Fair Value	$ (866,000)	0
Swap instrument one maturing April 27, 2025 | Cash flow hedging
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional amount of derivative	$ 100,000,000	0
Fixed Rate Per annum	1.088%
Fair Value	$ (540,000)	0
Swap instrument two maturing April 27, 2025 | Cash flow hedging
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional amount of derivative	$ 125,000,000	0
Fixed Rate Per annum	1.082%
Fair Value	$ (666,000)	0
Swap instrument four maturing October 18, 2026 | Cash flow hedging
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional amount of derivative	$ 75,000,000	0
Fixed Rate Per annum	0.977%
Fair Value	$ (422,000)	$ 0

Derivative Instruments - Power

Derivative Instruments - Power Purchase Agreements (Details) $ in Thousands	1 Months Ended	12 Months Ended
	Mar. 31, 2019agreement	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Derivative [Line Items]
Increase in utilities expense		$ 1,200	$ 700	$ 0
Reclassification of other comprehensive income to utilities expense		1,204	749	$ 0
Fair Value		$ (3,926)	(6,693)
Piscataway | Calpine Energy Solutions, LLC
Derivative [Line Items]
Expiration Date		Feb. 28, 2029
Fair Value		$ (2,162)	(2,919)
Chicago | Calpine Energy Solutions, LLC
Derivative [Line Items]
Expiration Date		Feb. 28, 2029
Fair Value		$ (1,764)	$ (3,774)
Power Purchase Agreements
Derivative [Line Items]
Term of agreement	10 years
Power Purchase Agreements | Chicago and Piscataway
Derivative [Line Items]
Number of agreements | agreement	2

Partners' Capital, Equity and_3

Partners' Capital, Equity and Incentive Compensation Plans (Narrative) (Details)

Jan. 15, 2021$ / shares

Jan. 07, 2021$ / shares

Sep. 18, 2020$ / shares

Jun. 19, 2020$ / shares

Mar. 20, 2020$ / shares

Dec. 20, 2019$ / shares

Sep. 19, 2019$ / shares

Jun. 25, 2019$ / shares

May 08, 2019shares

Mar. 20, 2019$ / shares

Dec. 21, 2018$ / shares

Jun. 25, 2018$ / sharesshares

Jun. 22, 2018

Mar. 15, 2018$ / sharesshares

May 04, 2017USD ($)itemshares

May 04, 2015shares

Mar. 31, 2019

Mar. 31, 2019shares

Dec. 31, 2020USD ($)Partnershipitem$ / sharesshares

Dec. 31, 2019USD ($)shares

Dec. 31, 2018USD ($)

Jun. 30, 2020$ / sharesshares

May 31, 2020USD ($)

Jun. 30, 2019USD ($)$ / shares

May 09, 2019shares

Feb. 28, 2019$ / sharesshares

May 03, 2015shares

Partners Capital And Distributions [Line Items]

Number of classes of partnership units outstanding | Partnership

4

Vesting percentage

8.375%

Equity based compensation expense unrecognized | $

$ 26,500,000

Equity based compensation expense vesting period

10 months 24 days

Dividend rate (as a percent)

7.125%

Proceeds from issuance or sale of equity | $

$ (286,300,000)

Common stock issuance proceeds, net of costs | $

$ 285,352,000

$ 268,259,000

$ 0

Preferred stock, liquidation preference (in dollars per share) | $ / shares

$ 25

Preferred stock, shares issued (in shares) | shares

4,280,000

At Market

Partners Capital And Distributions [Line Items]

Initial forward sale price per share, calculation value

100.00%

QTS Realty Trust, Inc. Employee Stock Purchase Plan

Partners Capital And Distributions [Line Items]

Shares reserved for purchase under plan | shares

250,000

2017 Plan

Partners Capital And Distributions [Line Items]

Minimum period of service

30 days

Minimum hours per week of service | item

30

Employee stock purchase plan number of purchase period per year | item

4

Common stock

Partners Capital And Distributions [Line Items]

Dividend paid to common stockholders (in dollars per share) | $ / shares

$ 0.47

$ 0.47

$ 0.47

$ 0.44

$ 0.44

$ 0.44

$ 0.44

$ 0.41

Shares issued | shares

4,000,000

Common stock | Underwritten Offering

Partners Capital And Distributions [Line Items]

Share Price | $ / shares

$ 64.90

Common stock | Subsequent Event

Partners Capital And Distributions [Line Items]

Dividend paid to common stockholders (in dollars per share) | $ / shares

$ 0.47

Class O Units

Partners Capital And Distributions [Line Items]

Equity based compensation awards intrinsic value | $

$ 48,300,000

Class B Common Stock

Partners Capital And Distributions [Line Items]

Number of votes per share | item

50

Class A Common Stock | Underwritten Offering

Partners Capital And Distributions [Line Items]

Shares issued | shares

4,000,000

Common stock, shares authorized (in shares) | shares

7,762,500

Shares to be issued on a forward basis (in shares) | shares

3,762,500

Common stock, par value (in dollars per share) | $ / shares

$ 0.01

Class A Common Stock | Prior At Market Offering Program

Partners Capital And Distributions [Line Items]

Maximum value of stock which may be issued | $

$ 400,000,000

Common stock, par value (in dollars per share) | $ / shares

$ 0.01

Class A Common Stock | At Market

Partners Capital And Distributions [Line Items]

Maximum value of stock which may be issued | $

$ 500,000,000

Class A Common Stock | 2017 Plan

Partners Capital And Distributions [Line Items]

Shares reserved for purchase under plan | shares

239,989

Discount rate of purchase price of common stock

10.00%

Series A Redeemable Perpetual Preferred

Partners Capital And Distributions [Line Items]

Preferred stock, liquidation preference (in dollars per share) | $ / shares

$ 25

Preferred stock redemption price per share | $ / shares

$ 25

Threshold period of redemption of preferred stock

120 days

Ownership interest

50.00%

Convertible preferred stock par value | $ / shares

$ 0.01

Share cap price | $ / shares

1.46929

Series A Redeemable Perpetual Preferred | Underwriter's Option

Partners Capital And Distributions [Line Items]

Preferred stock, shares issued (in shares) | shares

280,000

Series A Redeemable Perpetual Preferred | Subsequent Event

Partners Capital And Distributions [Line Items]

Dividend paid to common stockholders (in dollars per share) | $ / shares

$ 0.45

Series B Convertible preferred stock

Partners Capital And Distributions [Line Items]

Dividend rate (as a percent)

6.50%

Preferred stock, liquidation preference (in dollars per share) | $ / shares

$ 100

Preferred stock, shares issued (in shares) | shares

3,162,500

Share cap price | $ / shares

$ 5.1020

Minimum percentage of closing sale price of common stock under preferred stock conversion (as a percent)

150.00%

Maximum trading days of closing sale price of common stock under preferred stock conversion including the last trading day (in days)

30 days

Period of average daily volume weighted average price

10 days

Series B Convertible preferred stock | Underwriter's Option

Partners Capital And Distributions [Line Items]

Preferred stock, shares issued (in shares) | shares

412,500

Series B Convertible preferred stock | Subsequent Event

Partners Capital And Distributions [Line Items]

Dividend paid to common stockholders (in dollars per share) | $ / shares

$ 1.63

Series B Convertible preferred stock

Partners Capital And Distributions [Line Items]

Dividend rate (as a percent)

6.50%

Minimum trading days of closing sale price of common stock under preferred stock conversion (in days)

20 days

Maximum trading days of closing sale price of common stock under preferred stock conversion including the last trading day (in days)

30 days

Conversion of stock, conversion rate

2.1404

Preferred Units Series A | QualityTech, LP

Partners Capital And Distributions [Line Items]

Conversion ratio, stock for cash or stock

1

Chief Executive Officer | Class B Common Stock

Partners Capital And Distributions [Line Items]

Percentage of operating partnership unit exchanged

2.00%

Minimum | 2017 Plan

Partners Capital And Distributions [Line Items]

Minimum percentage of combined voting power

500.00%

Deductions per paycheck for purchase of shares | $

$ 20

Holding period after purchase of share

1 year

Maximum | 2017 Plan

Partners Capital And Distributions [Line Items]

Deductions per paycheck for purchase of shares | $

$ 1,000

Maximum | Common stock | Underwritten Offering

Partners Capital And Distributions [Line Items]

Common stock, shares authorized (in shares) | shares

4,400,000

Restricted Class A Common Stock

Partners Capital And Distributions [Line Items]

Options outstanding | shares

100,000

Performance-Based FFO Units | Minimum | Class A Common Stock

Partners Capital And Distributions [Line Items]

Percentage of target award

0.00%

Performance-Based FFO Units | Maximum | Class A Common Stock

Partners Capital And Distributions [Line Items]

Percentage of target award

200.00%

2013 Equity Incentive Plan | Class A Common Stock

Partners Capital And Distributions [Line Items]

Authorized shares to be issued under the plan | shares

5,900,000

1,750,000

Additional shares available for issuance under plan approved by stockholders | shares

1,100,000

3,000,000

Second portion | Performance-Based FFO Units

Partners Capital And Distributions [Line Items]

Vesting period

3 years

Partners' Capital, Equity and_4

Partners' Capital, Equity and Incentive Compensation Plans (Summary of Award Activity Under 2010 Equity Incentive Plan and 2013 Equity Incentive Plan and Related Information) (Details) - $ / shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
2010 Equity Incentive Plan | Class O Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Beginning balance, number of units (in shares)	82,310	102,279	568,040
Number of units, granted (in shares)	0	0	0
Number of units, exercised/vested (in shares)	(6,875)	(19,969)	(465,761)
Number of units, cancelled/expired (in shares)	0	0	0
Ending balance, number of units (in shares)	75,435	82,310	102,279
Beginning balance, weighted average exercise price units (in dollars per share)	$ 24.97	$ 24.05	$ 23.52
Weighted average exercise price units, granted (in dollars per share)	0	0	0
Weighted average exercise price units, exercised (in dollars per share)	25	20.25	23.40
Weighted average exercise price units, cancelled/expired (in dollars per share)	0	0	0
Ending balance, weighted average exercise price units (in dollars per share)	25	24.97	24.05
Beginning balance, weighted average fair value (in dollars per share)	5.97	5.67	5
Weighted average fair value, granted (in dollars per share)	0	0	0
Weighted average fair value, exercised (in dollars per share)	4.49	4.42	4.76
Weighted average fair value, cancelled/ expired (in dollars per share)	0	0	0
Ending balance, weighted average fair value (in dollars per share)	$ 6.11	$ 5.97	$ 5.67
2013 Equity Incentive Plan | Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Beginning balance, options outstanding (in shares)	1,934,838	2,037,163	1,369,270
Options, granted (in shares)	99,872	135,594	674,081
Options, exercised (in shares)	(98,303)	(125,213)	(6,188)
Options, cancelled/expired (in shares)	0	(112,706)	0
Ending balance, options outstanding (in shares)	1,936,407	1,934,838	2,037,163
Beginning balance, weighted average exercise price options outstanding (in dollars per share)	$ 37.11	$ 36.86	$ 38.18
Weighted average exercise price options outstanding, granted (in dollars per share)	56.84	42.27	34.05
Weighted average exercise price options outstanding, exercised (in dollars per share)	28.84	30.80	21.50
Weighted average exercise price options outstanding, cancelled/expired (in dollars per share)	0	45.86	0
Ending balance, weighted average exercise price options outstanding (in dollars per share)	38.55	37.11	36.86
Beginning balance, weighted average fair value, options (in dollars per share)	7.05	7.10	7.80
Weighted average fair value, granted, options (in dollars per share)	9.35	7.62	5.63
Weighted average fair value, vested, options (in dollars per share)	5.18	6.21	3.68
Weighted average fair value, cancelled/expired, options (in dollars per share)	0	9.43	0
Ending balance, weighted average fair value, options (in dollars per share)	$ 7.26	$ 7.05	$ 7.10
2013 Equity Incentive Plan | Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Beginning balance, number of units (in shares)	389,750	420,309	381,864
Number of units, granted (in shares)	302,591	274,564	348,152
Number of units, exercised/vested (in shares)	(264,466)	(279,429)	(224,660)
Number of units, cancelled/expired (in shares)	(11,379)	(25,694)	(85,047)
Ending balance, number of units (in shares)	416,496	389,750	420,309
Beginning balance, weighted average exercise price units (in dollars per share)	$ 39.67	$ 37.83	$ 46.37
Weighted average exercise price units, granted (in dollars per share)	57.47	42.25	35.27
Weighted average exercise price units, exercised (in dollars per share)	39.89	39.20	46.23
Weighted average exercise price units, cancelled/expired (in dollars per share)	49.38	42.17	43.50
Ending balance, weighted average exercise price units (in dollars per share)	$ 52.20	$ 39.67	$ 37.83
2013 Equity Incentive Plan | Performance-Based Relative TSR Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Beginning balance, number of units (in shares)	84,350	0	0
Number of units, granted (in shares)	84,202	86,089	0
Number of units, exercised/vested (in shares)	0	0	0
Number of units, cancelled/expired (in shares)	0	(1,739)	0
Ending balance, number of units (in shares)	168,552	84,350	0
Weighted average exercise price units, exercised (in dollars per share)	$ 0	$ 0	$ 0
Beginning balance, weighted average fair value, options (in dollars per share)	54.64	0	0
Weighted average fair value, granted, options (in dollars per share)	79.18	54.64	0
Weighted average fair value, cancelled/expired, options (in dollars per share)	0	54.64	0
Ending balance, weighted average fair value, options (in dollars per share)	$ 66.90	$ 54.64	$ 0
2013 Equity Incentive Plan | Performance-Based FFO Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Beginning balance, number of units (in shares)	84,350	0	0
Number of units, granted (in shares)	84,202	86,089	0
Number of units, performance adjustment (in shares)	59,844
Number of units, exercised/vested (in shares)	(96,129)	0	0
Number of units, cancelled/expired (in shares)	0	(1,739)	0
Ending balance, number of units (in shares)	132,267	84,350	0
Weighted average exercise price units, performance adjustment (in dollars per share)	$ 42.01
Weighted average exercise price units, exercised (in dollars per share)	42.01	$ 0	$ 0
Beginning balance, weighted average fair value, options (in dollars per share)	42.01	0	0
Weighted average fair value, granted, options (in dollars per share)	56.84	42.01	0
Weighted average fair value, cancelled/expired, options (in dollars per share)	0	42.01	0
Ending balance, weighted average fair value, options (in dollars per share)	$ 51.45	$ 42.01	$ 0

Partners' Capital, Equity and_5

Partners' Capital, Equity and Incentive Compensation Plans (Summary of Assumptions and Fair Values for Restricted Stock and Options to Purchase Shares of Class A Common Stock Granted) (Details) - $ / shares	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value of TSR units granted	79.18	54.64
Expected term (years)	5 years 6 months	5 years 6 months
Expected volatility	27.00%	28.00%	28.00%
Expected dividend yield			4.82%
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value of restricted stock granted	$ 56.84	$ 42.01	$ 34.03
Fair value of options granted	$ 9.35	$ 7.56	$ 5.55
Expected term (years)			5 years 6 months
Expected dividend yield	3.31%	3.89%
Expected risk-free interest rates	0.61%	2.33%	2.69%
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value of restricted stock granted	$ 65.96	$ 51.25	$ 54.01
Fair value of options granted		$ 8.28	$ 5.64
Expected term (years)			6 years
Expected dividend yield		4.19%
Expected risk-free interest rates		2.56%	2.73%

Partners' Capital, Equity and_6

Partners' Capital, Equity and Incentive Compensation Plans (Summary of Information About Awards Outstanding) (Details)	12 Months Ended
	Dec. 31, 2020$ / sharesshares
QualityTech LP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards outstanding	75,435
QTS Realty Trust, Inc.
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards outstanding	2,653,722
QTS Realty Trust, Inc. | Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards outstanding	416,496
Remaining term of awards	1 year
QTS Realty Trust, Inc. | Performance-Based Relative TSR Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards outstanding	168,552
Remaining term of awards	10 months 24 days
QTS Realty Trust, Inc. | Performance-Based FFO Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards outstanding	132,267
Remaining term of awards	8 months 12 days
QTS Realty Trust, Inc. | Options to purchase Class A common stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Lower limit of exercise price | $ / shares	$ 21
Upper limit of exercise price | $ / shares	$ 56.84
Awards outstanding	1,936,407
Remaining term of awards	10 months 24 days
Class O Units | QualityTech LP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Upper limit of exercise price | $ / shares	$ 25
Awards outstanding	75,435

Partners' Capital, Equity and_7

Partners' Capital, Equity and Incentive Compensation Plans (Schedule of Quarterly Cash Dividends) (Details) - USD ($) $ / shares in Units, $ in Thousands	Jan. 15, 2021	Jan. 07, 2021	Sep. 30, 2020	Sep. 18, 2020	Jun. 30, 2020	Jun. 19, 2020	Mar. 31, 2020	Mar. 20, 2020	Dec. 31, 2019	Dec. 20, 2019	Sep. 30, 2019	Sep. 19, 2019	Jun. 30, 2019	Jun. 25, 2019	Mar. 31, 2019	Mar. 20, 2019	Dec. 31, 2018	Dec. 21, 2018	Jun. 25, 2018	Jun. 22, 2018	Mar. 15, 2018	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Dividend rate (as a percent)																					7.125%
Preferred stock, shares issued (in shares)																					4,280,000
Preferred stock issuance proceeds, net of costs																							$ 0	$ 0	$ 407,477
Preferred stock, liquidation preference (in dollars per share)																					$ 25
Series A Redeemable Perpetual Preferred
Dividend rate (as a percent)																							7.125%	7.125%
Preferred stock, shares issued (in shares)									4,280,000														4,280,000	4,280,000
Preferred stock, liquidation preference (in dollars per share)									$ 25														$ 25	$ 25
Series A Preferred Stock
Dividend paid to common stockholders (in dollars per share)			$ 0.45		$ 0.45		$ 0.45		$ 0.45		$ 0.45		$ 0.45		$ 0.45		$ 0.45
Aggregate Dividend/Distribution Amount (in millions)			$ 1,900		$ 1,900		$ 1,900		$ 1,900		$ 1,900		$ 1,900		$ 1,900		$ 1,900						$ 7,600	$ 7,600
Series B Preferred Stock
Dividend paid to common stockholders (in dollars per share)			$ 1.63		$ 1.63		$ 1.63		$ 1.63		$ 1.63		$ 1.63		$ 1.63		$ 1.63
Aggregate Dividend/Distribution Amount (in millions)			$ 5,100		$ 5,100		$ 5,100		$ 5,100		$ 5,100		$ 5,100		$ 5,100		$ 5,100						$ 20,400	20,400
Series A Redeemable Perpetual Preferred
Preferred stock redemption price per share																							$ 25
Threshold period of redemption of preferred stock																							120 days
Ownership interest																							50.00%
Convertible preferred stock par value																							$ 0.01
Preferred stock, liquidation preference (in dollars per share)																							25
Share cap price																							$ 1.46929
Series B Convertible preferred stock
Dividend rate (as a percent)																				6.50%
Minimum trading days of closing sale price of common stock under preferred stock conversion (in days)																							20 days
Maximum trading days of closing sale price of common stock under preferred stock conversion including the last trading day (in days)																							30 days
Series B Convertible preferred stock
Dividend rate (as a percent)																			6.50%
Preferred stock, shares issued (in shares)																			3,162,500
Minimum percentage of closing sale price of common stock under preferred stock conversion (as a percent)																							150.00%
Maximum trading days of closing sale price of common stock under preferred stock conversion including the last trading day (in days)																							30 days
Preferred stock, liquidation preference (in dollars per share)																			$ 100
Period of average daily volume weighted average price																							10 days
Share cap price																							$ 5.1020
Subsequent Event | Series A Redeemable Perpetual Preferred
Dividend paid to common stockholders (in dollars per share)	$ 0.45
Subsequent Event | Series B Convertible preferred stock
Dividend paid to common stockholders (in dollars per share)	$ 1.63
Underwriter's Option | Series A Redeemable Perpetual Preferred
Preferred stock, shares issued (in shares)																					280,000
Underwriter's Option | Series B Convertible preferred stock
Preferred stock, shares issued (in shares)																			412,500
Underwritten Offering | Class A Common Stock
Shares issued																						4,000,000
Common stock
Dividend paid to common stockholders (in dollars per share)				$ 0.47		$ 0.47		$ 0.47		$ 0.44		$ 0.44		$ 0.44		$ 0.44		$ 0.41
Aggregate Dividend/Distribution Amount (in millions)				$ 32,000		$ 31,500		$ 31,500		$ 28,600		$ 27,300		$ 27,300		$ 27,300		$ 23,700					$ 123,600	$ 105,600
Shares issued																								4,000,000
Common stock | Subsequent Event
Dividend paid to common stockholders (in dollars per share)		$ 0.47

Partners' Capital, Equity and_8

Partners' Capital, Equity and Incentive Compensation Plans (Summary of Equity Issued) (Details) - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Subsidiary, Sale of Stock [Line Items]
Shares and net proceeds available as of December 31, 2019	3,795
Shares and net proceeds available as of December 31, 2019	$ 173,776
Forward Shares Sold/Settled , Number of Shares	9,961	3,795
Proceeds From Issuance Or Sale Of Equity1	$ 587,550	$ 173,776
Proceeds from issuance or sale of equity		177,800
Dividends, common stock		$ 4,000
February 2019 Offering - Settlement
Subsidiary, Sale of Stock [Line Items]
Forward shares (Settled) (in shares)	(931)
Net Proceeds (Received)	$ (35,841)
June '19 ATM
Subsidiary, Sale of Stock [Line Items]
Forward shares (Settled) (in shares)	(4,981)
Forward Shares Sold (in shares)	4,550
Net Proceeds (Received)	$ (250,496)
Net Proceeds Available	$ 243,577
May 2020 Current ATM Program - Sales
Subsidiary, Sale of Stock [Line Items]
Forward Shares Sold (in shares)	3,128
Net Proceeds Available	$ 189,640
June 2020 Offering - Sales
Subsidiary, Sale of Stock [Line Items]
Forward Shares Sold (in shares)	4,400
Net Proceeds Available	$ 266,894

Related Party Transactions (Sum

Related Party Transactions (Summary of Related Party Transactions) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Related Party Transaction [Line Items]
Other	$ 19,510	$ 15,695	$ 36,904
Affiliated Entity
Related Party Transaction [Line Items]
Lease term of facility with global cloud-based software company	10 years
Ownership interest	50.00%
Tax, utility, insurance and other reimbursement	$ 694	967	724
Rent expense	1,027	1,014	1,014
Capital assets acquired	0	704	464
Total	1,721	2,685	$ 2,202
Development Fees | Affiliated Entity
Related Party Transaction [Line Items]
Other	900	600
Management Fees | Affiliated Entity
Related Party Transaction [Line Items]
Other	$ 800	$ 600

Employee Benefit Plan (Narrativ

Employee Benefit Plan (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plan Disclosure [Line Items]
Employer contribution on employee benefit plan	$ 2.6	$ 2.5	$ 2.5
First 6% of Employee Contribution
Defined Benefit Plan Disclosure [Line Items]
Employer contribution rate as a percentage of employee contribution					50.00%
Percentage contribution from employees					6.00%
First 1% Percent of Contributions
Defined Benefit Plan Disclosure [Line Items]
Employer contribution rate as a percentage of employee contribution				100.00%
Percentage contribution from employees				1.00%
Next 5 % Percent of Employee Contribution
Defined Benefit Plan Disclosure [Line Items]
Employer contribution rate as a percentage of employee contribution				50.00%
Percentage contribution from employees				5.00%

Noncontrolling Interest (Narrat

Noncontrolling Interest (Narrative) (Details)	12 Months Ended
	Dec. 31, 2020	Oct. 13, 2013
Stock conversion ratio	1
Previous Owners of QualityTech LP | QualityTech, LP
QualityTech LP ownership percentage in operating partnership	9.20%	21.20%

Earnings per share (Computation

Earnings per share (Computation of Basic and Diluted Net Income per Share) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Earnings Per Share [Abstract]
Net income (loss)	$ (10,660)	$ 6,907	$ 10,209	$ 8,120	$ (3,606)	$ 6,588	$ 7,535	$ 21,148	$ 14,576	$ 31,665	$ (7,175)
(Income) loss attributable to noncontrolling interests									1,330	(374)	2,715
Preferred stock dividends									(28,180)	(28,180)	(16,666)
Earnings attributable to participating securities									(16,360)	(7,828)	(947)
Net loss available to common stockholders after allocation to participating securities									$ (28,634)	$ (4,717)	$ (22,073)
Weighted average shares outstanding - basic (in shares)									60,717,301	54,836,801	50,432,590
Effect of Class O units, TSR units, FFO units and options to purchase Class A common stock on an "as if" converted basis (in shares)									0	0	0
Weighted average shares outstanding - diluted (in shares)									60,717,301	54,836,801	50,432,590
Basic net loss per share (in dollars per share)	$ (0.33)	$ (0.07)	$ (0.05)	$ (0.01)	$ (0.20)	$ (0.05)	$ (0.03)	$ 0.20	$ (0.47)	$ (0.09)	$ (0.44)
Diluted net loss per share (in dollars per share)	$ (0.33)	$ (0.07)	$ (0.05)	$ (0.01)	$ (0.20)	$ (0.05)	$ (0.03)	$ 0.20	$ (0.47)	$ (0.09)	$ (0.44)

Earnings per share (Antidilutiv

Earnings per share (Antidilutive) (Details) - shares shares in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Class A Common Stock
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Antidilutive shares excluded from the computation of diluted net earning per share	6,648	6,671	6,653
Class O units, TSR units, FFO units and options to purchase common stock on an "as if" converted basis
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Antidilutive shares excluded from the computation of diluted net earning per share	1,118	518	350
Series B Convertible preferred stock
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
Antidilutive shares excluded from the computation of diluted net earning per share	6,778	6,729	3,484

Contracts with Customers (Detai

Contracts with Customers (Details) $ in Thousands	Dec. 31, 2020USD ($)
Revenue from Contract with Customer [Abstract]
2021	$ 435,906
2022	359,860
2023	263,413
2024	214,215
2025	165,002
Thereafter	493,839
Total	$ 1,932,235

Fair Value of Financial Instr_2

Fair Value of Financial Instruments (Details) - USD ($) $ in Millions	Dec. 31, 2020	Oct. 07, 2020
Senior Notes due 2028
Fair Value Of Financial Instruments [Line Items]
Interest rate	3.875%	3.875%
Senior Notes | Fair Value Measurements, Level 2
Fair Value Of Financial Instruments [Line Items]
Fair value of loan based on current market rates	$ 508.8

Quarterly Financial Informati_3

Quarterly Financial Information (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Effect of Fourth Quarter Events [Line Items]
Revenues	$ 143,897	$ 137,538	$ 131,640	$ 126,292	$ 123,707	$ 125,255	$ 119,167	$ 112,689	$ 539,368	$ 480,818	$ 450,524
Operating income	17,151	15,016	17,859	15,631	4,218	13,606	14,598	28,734	65,657	61,156	18,661
Net income (loss)	(10,660)	6,907	10,209	8,120	(3,606)	6,588	7,535	21,148	14,576	31,665	(7,175)
Net income (loss) attributable to QTS Realty Trust, Inc.	(8,922)	6,925	9,892	8,010	(2,511)	6,637	7,483	19,558	15,906	31,291	(4,460)
Net income (loss) attributable to common stockholders	$ (15,967)	$ (120)	$ 2,847	$ 965	$ (9,556)	$ (408)	$ 438	$ 12,513	$ (12,274)	$ 3,111	$ (21,126)
Basic (in dollars per share)	$ (0.33)	$ (0.07)	$ (0.05)	$ (0.01)	$ (0.20)	$ (0.05)	$ (0.03)	$ 0.20	$ (0.47)	$ (0.09)	$ (0.44)
Diluted (in dollars per share)	$ (0.33)	$ (0.07)	$ (0.05)	$ (0.01)	$ (0.20)	$ (0.05)	$ (0.03)	$ 0.20	$ (0.47)	$ (0.09)	$ (0.44)

Subsequent Events (Narrative) (

Subsequent Events (Narrative) (Details) - USD ($) $ / shares in Units, $ in Thousands	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Feb. 03, 2021
Subsequent Event [Line Items]
Net proceeds									$ 285,352	$ 268,259	$ 0
Series A Preferred Stock
Subsequent Event [Line Items]
Dividend paid to common stockholders (in dollars per share)	$ 0.45	$ 0.45	$ 0.45	$ 0.45	$ 0.45	$ 0.45	$ 0.45	$ 0.45
Series B Preferred Stock
Subsequent Event [Line Items]
Dividend paid to common stockholders (in dollars per share)	$ 1.63	$ 1.63	$ 1.63	$ 1.63	$ 1.63	$ 1.63	$ 1.63	$ 1.63
Subsequent Event
Subsequent Event [Line Items]
Cash dividend payable per common share												$ 0.50
Subsequent Event | Series A Preferred Stock
Subsequent Event [Line Items]
Cash dividend payable per common share												0.45
Subsequent Event | Series B Preferred Stock
Subsequent Event [Line Items]
Cash dividend payable per common share												$ 1.63

Schedule II - Valuation and Q_2

Schedule II - Valuation and Qualifying Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Allowance for uncollectible receivables
Balance at beginning of period	$ 2,279	$ 3,764	$ 11,453
Charge to expenses	5,051	2,859	(2,275)
Additions/(deductions)	(1,891)	(4,344)	(5,414)
Balance at end of period	5,439	2,279	3,764
Valuation allowance for deferred tax assets
Balance at beginning of period	24,747	8,361	713
Charge to expenses	1,877	16,386	7,648
Additions/(deductions)	0	0	0
Balance at end of period	$ 26,624	$ 24,747	$ 8,361

Schedule III - Real Estate In_2

Schedule III - Real Estate Investments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Initial costs of land	$ 92,947
Initial costs of buildings and improvements	373,326
Initial costs of construction in progress	349,243
Costs capitalized subsequent to acquisition, land	72,162
Costs capitalized subsequent to acquisition, buildings and improvements	2,465,934
Costs capitalized subsequent to acquisition, construction in progress	679,521
Gross carrying amount, land	165,109
Gross carrying amount, buildings and improvements	2,839,260
Gross carrying amount, construction in progress	1,028,764
Accumulated depreciation and amortization	(702,944)	$ (558,560)	$ (467,644)	$ (394,823)
Owned Properties
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Initial costs of land	92,947
Initial costs of buildings and improvements	312,254
Initial costs of construction in progress	349,243
Costs capitalized subsequent to acquisition, land	72,162
Costs capitalized subsequent to acquisition, buildings and improvements	2,443,381
Costs capitalized subsequent to acquisition, construction in progress	679,142
Gross carrying amount, land	165,109
Gross carrying amount, buildings and improvements	2,755,635
Gross carrying amount, construction in progress	1,028,385
Accumulated depreciation and amortization	(674,468)
Owned Properties | Ashburn, Virginia (DC-1)
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Initial costs of land	16,476
Initial costs of buildings and improvements	0
Initial costs of construction in progress	0
Costs capitalized subsequent to acquisition, land	0
Costs capitalized subsequent to acquisition, buildings and improvements	371,725
Costs capitalized subsequent to acquisition, construction in progress	13,653
Gross carrying amount, land	16,476
Gross carrying amount, buildings and improvements	371,725
Gross carrying amount, construction in progress	13,653
Accumulated depreciation and amortization	$ (23,423)
Year of acquisition	2017
Owned Properties | Ashburn, Virginia (DC-2)
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Initial costs of land	$ 0
Initial costs of buildings and improvements	0
Initial costs of construction in progress	20,603
Costs capitalized subsequent to acquisition, land	0
Costs capitalized subsequent to acquisition, buildings and improvements	0
Costs capitalized subsequent to acquisition, construction in progress	109,254
Gross carrying amount, land	0
Gross carrying amount, buildings and improvements	0
Gross carrying amount, construction in progress	129,857
Accumulated depreciation and amortization	$ 0
Year of acquisition	2019
Owned Properties | Ashburn, Virginia (DC-3)
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Initial costs of land	$ 0
Initial costs of buildings and improvements	0
Initial costs of construction in progress	35,198
Costs capitalized subsequent to acquisition, land	0
Costs capitalized subsequent to acquisition, buildings and improvements	0
Costs capitalized subsequent to acquisition, construction in progress	7,194
Gross carrying amount, land	0
Gross carrying amount, buildings and improvements	0
Gross carrying amount, construction in progress	42,392
Accumulated depreciation and amortization	$ 0
Year of acquisition	2017
Owned Properties | Atlanta, Georgia (DC-1)
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Initial costs of land	$ 2,078
Initial costs of buildings and improvements	35,473
Initial costs of construction in progress	2,209
Costs capitalized subsequent to acquisition, land	11,212
Costs capitalized subsequent to acquisition, buildings and improvements	538,751
Costs capitalized subsequent to acquisition, construction in progress	991
Gross carrying amount, land	13,289
Gross carrying amount, buildings and improvements	574,224
Gross carrying amount, construction in progress	3,200
Accumulated depreciation and amortization	$ (221,800)
Year of acquisition	2006
Owned Properties | Atlanta, Georgia (DC-2)
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Initial costs of land	$ 10,569
Initial costs of buildings and improvements	0
Initial costs of construction in progress	0
Costs capitalized subsequent to acquisition, land	0
Costs capitalized subsequent to acquisition, buildings and improvements	124,864
Costs capitalized subsequent to acquisition, construction in progress	124,252
Gross carrying amount, land	10,569
Gross carrying amount, buildings and improvements	124,864
Gross carrying amount, construction in progress	124,252
Accumulated depreciation and amortization	$ (2,737)
Year of acquisition	2017
Owned Properties | Atlanta, Georgia Land
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Initial costs of land	$ 23,572
Initial costs of buildings and improvements	0
Initial costs of construction in progress	52,754
Costs capitalized subsequent to acquisition, land	7,726
Costs capitalized subsequent to acquisition, buildings and improvements	1,054
Costs capitalized subsequent to acquisition, construction in progress	10,866
Gross carrying amount, land	31,298
Gross carrying amount, buildings and improvements	1,054
Gross carrying amount, construction in progress	63,619
Accumulated depreciation and amortization	$ (449)
Year of acquisition	2017, 2019, 2020
Owned Properties | Chicago, Illinois
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Initial costs of land	$ 0
Initial costs of buildings and improvements	0
Initial costs of construction in progress	17,764
Costs capitalized subsequent to acquisition, land	9,400
Costs capitalized subsequent to acquisition, buildings and improvements	250,335
Costs capitalized subsequent to acquisition, construction in progress	86,353
Gross carrying amount, land	9,400
Gross carrying amount, buildings and improvements	250,335
Gross carrying amount, construction in progress	104,117
Accumulated depreciation and amortization	$ (34,134)
Year of acquisition	2014
Owned Properties | Dulles, Virginia
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Initial costs of land	$ 3,154
Initial costs of buildings and improvements	29,583
Initial costs of construction in progress	0
Costs capitalized subsequent to acquisition, land	0
Costs capitalized subsequent to acquisition, buildings and improvements	24,740
Costs capitalized subsequent to acquisition, construction in progress	4,148
Gross carrying amount, land	3,154
Gross carrying amount, buildings and improvements	54,323
Gross carrying amount, construction in progress	4,148
Accumulated depreciation and amortization	$ (17,191)
Year of acquisition	2017
Owned Properties | Eemshaven, Netherlands
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Initial costs of land	$ 0
Initial costs of buildings and improvements	0
Initial costs of construction in progress	29,915
Costs capitalized subsequent to acquisition, land	5,366
Costs capitalized subsequent to acquisition, buildings and improvements	21,712
Costs capitalized subsequent to acquisition, construction in progress	17,616
Gross carrying amount, land	5,366
Gross carrying amount, buildings and improvements	21,712
Gross carrying amount, construction in progress	47,531
Accumulated depreciation and amortization	$ (1,017)
Year of acquisition	2019
Owned Properties | Fort Worth, Texas
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Initial costs of land	$ 136
Initial costs of buildings and improvements	610
Initial costs of construction in progress	48,984
Costs capitalized subsequent to acquisition, land	8,943
Costs capitalized subsequent to acquisition, buildings and improvements	123,444
Costs capitalized subsequent to acquisition, construction in progress	(47,920)
Gross carrying amount, land	9,079
Gross carrying amount, buildings and improvements	124,054
Gross carrying amount, construction in progress	1,064
Accumulated depreciation and amortization	$ (8,967)
Year of acquisition	2016
Owned Properties | Groningen, Netherlands
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Initial costs of land	$ 1,743
Initial costs of buildings and improvements	8,640
Initial costs of construction in progress	0
Costs capitalized subsequent to acquisition, land	153
Costs capitalized subsequent to acquisition, buildings and improvements	2,566
Costs capitalized subsequent to acquisition, construction in progress	3,730
Gross carrying amount, land	1,896
Gross carrying amount, buildings and improvements	11,206
Gross carrying amount, construction in progress	3,730
Accumulated depreciation and amortization	$ (1,456)
Year of acquisition	2019
Owned Properties | Hillsboro, Oregon
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Initial costs of land	$ 0
Initial costs of buildings and improvements	0
Initial costs of construction in progress	25,657
Costs capitalized subsequent to acquisition, land	18,414
Costs capitalized subsequent to acquisition, buildings and improvements	34,594
Costs capitalized subsequent to acquisition, construction in progress	52,733
Gross carrying amount, land	18,414
Gross carrying amount, buildings and improvements	34,594
Gross carrying amount, construction in progress	78,390
Accumulated depreciation and amortization	$ (880)
Year of acquisition	2017
Owned Properties | Irving, Texas
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Initial costs of land	$ 0
Initial costs of buildings and improvements	5,808
Initial costs of construction in progress	0
Costs capitalized subsequent to acquisition, land	8,606
Costs capitalized subsequent to acquisition, buildings and improvements	386,467
Costs capitalized subsequent to acquisition, construction in progress	99,591
Gross carrying amount, land	8,606
Gross carrying amount, buildings and improvements	392,275
Gross carrying amount, construction in progress	99,591
Accumulated depreciation and amortization	$ (81,213)
Year of acquisition	2013
Owned Properties | Lenexa, Kansas
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Initial costs of land	$ 400
Initial costs of buildings and improvements	3,100
Initial costs of construction in progress	0
Costs capitalized subsequent to acquisition, land	37
Costs capitalized subsequent to acquisition, buildings and improvements	781
Costs capitalized subsequent to acquisition, construction in progress	0
Gross carrying amount, land	437
Gross carrying amount, buildings and improvements	3,881
Gross carrying amount, construction in progress	0
Accumulated depreciation and amortization	$ (703)
Year of acquisition	2011
Owned Properties | Manassas Virginia (DC-1)
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Initial costs of land	$ 0
Initial costs of buildings and improvements	0
Initial costs of construction in progress	27,484
Costs capitalized subsequent to acquisition, land	0
Costs capitalized subsequent to acquisition, buildings and improvements	25
Costs capitalized subsequent to acquisition, construction in progress	33,586
Gross carrying amount, land	0
Gross carrying amount, buildings and improvements	25
Gross carrying amount, construction in progress	61,070
Accumulated depreciation and amortization	$ (2)
Year of acquisition	2018
Owned Properties | Manassas Virginia (DC-2)
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Initial costs of land	$ 0
Initial costs of buildings and improvements	0
Initial costs of construction in progress	5,911
Costs capitalized subsequent to acquisition, land	0
Costs capitalized subsequent to acquisition, buildings and improvements	0
Costs capitalized subsequent to acquisition, construction in progress	92
Gross carrying amount, land	0
Gross carrying amount, buildings and improvements	0
Gross carrying amount, construction in progress	6,003
Accumulated depreciation and amortization	$ 0
Year of acquisition	2018
Owned Properties | Miami, Florida
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Initial costs of land	$ 1,777
Initial costs of buildings and improvements	6,955
Initial costs of construction in progress	0
Costs capitalized subsequent to acquisition, land	0
Costs capitalized subsequent to acquisition, buildings and improvements	24,934
Costs capitalized subsequent to acquisition, construction in progress	577
Gross carrying amount, land	1,777
Gross carrying amount, buildings and improvements	31,889
Gross carrying amount, construction in progress	577
Accumulated depreciation and amortization	$ (13,796)
Year of acquisition	2008
Owned Properties | Phoenix, Arizona
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Initial costs of land	$ 0
Initial costs of buildings and improvements	0
Initial costs of construction in progress	24,668
Costs capitalized subsequent to acquisition, land	0
Costs capitalized subsequent to acquisition, buildings and improvements	0
Costs capitalized subsequent to acquisition, construction in progress	13,061
Gross carrying amount, land	0
Gross carrying amount, buildings and improvements	0
Gross carrying amount, construction in progress	37,729
Accumulated depreciation and amortization	$ 0
Year of acquisition	2017
Owned Properties | Piscataway, New Jersey
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Initial costs of land	$ 7,466
Initial costs of buildings and improvements	80,366
Initial costs of construction in progress	13,900
Costs capitalized subsequent to acquisition, land	0
Costs capitalized subsequent to acquisition, buildings and improvements	41,810
Costs capitalized subsequent to acquisition, construction in progress	16,501
Gross carrying amount, land	7,466
Gross carrying amount, buildings and improvements	122,176
Gross carrying amount, construction in progress	30,401
Accumulated depreciation and amortization	$ (16,600)
Year of acquisition	2016
Owned Properties | Princeton, New Jersey
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Initial costs of land	$ 20,700
Initial costs of buildings and improvements	32,126
Initial costs of construction in progress	0
Costs capitalized subsequent to acquisition, land	0
Costs capitalized subsequent to acquisition, buildings and improvements	3,135
Costs capitalized subsequent to acquisition, construction in progress	5
Gross carrying amount, land	20,700
Gross carrying amount, buildings and improvements	35,261
Gross carrying amount, construction in progress	5
Accumulated depreciation and amortization	$ (6,319)
Year of acquisition	2014
Owned Properties | Richmond, Virginia
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Initial costs of land	$ 2,000
Initial costs of buildings and improvements	11,200
Initial costs of construction in progress	7,029
Costs capitalized subsequent to acquisition, land	180
Costs capitalized subsequent to acquisition, buildings and improvements	222,727
Costs capitalized subsequent to acquisition, construction in progress	113,548
Gross carrying amount, land	2,180
Gross carrying amount, buildings and improvements	233,927
Gross carrying amount, construction in progress	120,577
Accumulated depreciation and amortization	$ (84,389)
Year of acquisition	2010 & 2019
Owned Properties | Sacramento, California
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Initial costs of land	$ 1,481
Initial costs of buildings and improvements	52,753
Initial costs of construction in progress	0
Costs capitalized subsequent to acquisition, land	0
Costs capitalized subsequent to acquisition, buildings and improvements	13,546
Costs capitalized subsequent to acquisition, construction in progress	12
Gross carrying amount, land	1,481
Gross carrying amount, buildings and improvements	66,299
Gross carrying amount, construction in progress	12
Accumulated depreciation and amortization	$ (16,325)
Year of acquisition	2012
Owned Properties | San Antonio, Texas
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Initial costs of land	$ 0
Initial costs of buildings and improvements	0
Initial costs of construction in progress	37,167
Costs capitalized subsequent to acquisition, land	0
Costs capitalized subsequent to acquisition, buildings and improvements	0
Costs capitalized subsequent to acquisition, construction in progress	3,213
Gross carrying amount, land	0
Gross carrying amount, buildings and improvements	0
Gross carrying amount, construction in progress	40,380
Accumulated depreciation and amortization	$ 0
Year of acquisition	2020
Owned Properties | Santa Clara, California
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Initial costs of land	$ 0
Initial costs of buildings and improvements	15,838
Initial costs of construction in progress	0
Costs capitalized subsequent to acquisition, land	0
Costs capitalized subsequent to acquisition, buildings and improvements	101,505
Costs capitalized subsequent to acquisition, construction in progress	9,385
Gross carrying amount, land	0
Gross carrying amount, buildings and improvements	117,343
Gross carrying amount, construction in progress	9,385
Accumulated depreciation and amortization	$ (52,742)
Year of acquisition	2007
Owned Properties | Suwanee, Georgia (Atlanta-Suwanee)
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Initial costs of land	$ 1,395
Initial costs of buildings and improvements	29,802
Initial costs of construction in progress	0
Costs capitalized subsequent to acquisition, land	2,126
Costs capitalized subsequent to acquisition, buildings and improvements	154,665
Costs capitalized subsequent to acquisition, construction in progress	6,701
Gross carrying amount, land	3,521
Gross carrying amount, buildings and improvements	184,467
Gross carrying amount, construction in progress	6,701
Accumulated depreciation and amortization	$ (90,323)
Year of acquisition	2005
Leased Properties
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Initial costs of land	$ 0
Initial costs of buildings and improvements	61,072
Initial costs of construction in progress	0
Costs capitalized subsequent to acquisition, land	0
Costs capitalized subsequent to acquisition, buildings and improvements	22,553
Costs capitalized subsequent to acquisition, construction in progress	379
Gross carrying amount, land	0
Gross carrying amount, buildings and improvements	83,625
Gross carrying amount, construction in progress	379
Accumulated depreciation and amortization	(28,476)
Leased Properties | Jersey City, New Jersey
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Initial costs of land	0
Initial costs of buildings and improvements	1,985
Initial costs of construction in progress	0
Costs capitalized subsequent to acquisition, land	0
Costs capitalized subsequent to acquisition, buildings and improvements	28,178
Costs capitalized subsequent to acquisition, construction in progress	223
Gross carrying amount, land	0
Gross carrying amount, buildings and improvements	30,163
Gross carrying amount, construction in progress	223
Accumulated depreciation and amortization	$ (15,455)
Year of acquisition	2006
Leased Properties | Overland Park, Kansas
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Initial costs of land	$ 0
Initial costs of buildings and improvements	0
Initial costs of construction in progress	0
Costs capitalized subsequent to acquisition, land	0
Costs capitalized subsequent to acquisition, buildings and improvements	866
Costs capitalized subsequent to acquisition, construction in progress	154
Gross carrying amount, land	0
Gross carrying amount, buildings and improvements	866
Gross carrying amount, construction in progress	154
Accumulated depreciation and amortization	(508)
Lease Facilities acquired in 2015
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Initial costs of land	0
Initial costs of buildings and improvements	59,087
Initial costs of construction in progress	0
Costs capitalized subsequent to acquisition, land	0
Costs capitalized subsequent to acquisition, buildings and improvements	(6,491)
Costs capitalized subsequent to acquisition, construction in progress	2
Gross carrying amount, land	0
Gross carrying amount, buildings and improvements	52,596
Gross carrying amount, construction in progress	2
Accumulated depreciation and amortization	$ (12,513)
Year of acquisition	2015

Schedule III - Real Estate In_3

Schedule III - Real Estate Investments - Impairment and Amount that Tax Basis of Net Real Estate Assets Less Than the Reported Amounts (Details) $ in Millions	12 Months Ended
	Dec. 31, 2020USD ($)
SEC Schedule, 12-28, Real Estate Companies, Investment in Real Estate and Accumulated Depreciation Disclosure [Abstract]
Reduction of costs capitalized	$ 24.9
Reduction of accumulated depreciation	13.5
Tax basis of investments, cost for income tax purposes	$ 4,220

Schedule III - Real Estate In_4

Schedule III - Real Estate Investments - Summary of Historical Cost and Accumulated Depreciation) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Property
Balance, beginning of period	$ 3,230,428	$ 2,812,856	$ 2,357,322
Disposals	(7,821)	(41,363)	(43,616)
Additions (acquisitions and improvements)	810,527	458,935	499,150
Balance, end of period	4,033,134	3,230,428	2,812,856
Accumulated depreciation
Balance, beginning of period	(558,560)	(467,644)	(394,823)
Disposals	6,577	28,172	30,139
Additions (depreciation and amortization expense)	(150,961)	(119,088)	(102,960)
Balance, end of period	$ (702,944)	$ (558,560)	$ (467,644)