Qts Realty Trust (QTS) 10-K 28 Feb 20 2019 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2019	Feb. 25, 2020	Jun. 30, 2019
Document Information [Line Items]
Document Type	10-K
Document Annual Report	true
Document Transition Report	false
Document Period End Date	Dec. 31, 2019
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
Entity Shell Company	false
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	FY
Entity Central Index Key	0001577368
Amendment Flag	false
Entity Public Float			$ 2.6
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		58,105,122
Class B Common Stock
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		128,408
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 [Member]
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
Qualitytech, LP
Document Information [Line Items]
Document Type	10-K
Document Annual Report	true
Document Transition Report	false
Document Period End Date	Dec. 31, 2019
Entity Registrant Name	QualityTech, LP
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	27-0707288
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	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	FY
Entity Central Index Key	0001561164
Amendment Flag	false

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Real Estate Assets
Land	$ 130,605	$ 105,541
Buildings, improvements and equipment	2,178,901	1,917,251
Less: Accumulated depreciation	(558,560)	(467,644)
Total real estate assets	1,750,946	1,555,148
Construction in progress	920,922	790,064
Real Estate Assets, net	2,671,868	2,345,212
Investments in unconsolidated entity	30,218
Operating lease right-of-use assets, net	57,141
Cash and cash equivalents	15,653	11,759
Rents and other receivables, net	81,181	55,093
Acquired intangibles, net	81,679	95,451
Deferred costs, net	52,363	45,096
Prepaid expenses	10,586	6,822
Goodwill	173,843	173,843
Assets held for sale		71,800
Other assets, net	49,001	56,893
TOTAL ASSETS	3,223,533	2,861,969
LIABILITIES
Unsecured credit facility, net	1,010,640	945,657
Senior notes, net of debt issuance costs	395,549	394,786
Finance leases and mortgage notes payable	46,876	4,674
Operating lease liabilities	64,416
Accounts payable and accrued liabilities	142,547	99,166
Dividends and distributions payable	34,500	29,633
Advance rents, security deposits and other liabilities	18,027	29,709
Derivative liabilities	26,609	2,970
Liabilities held for sale		24,349
Deferred income taxes	749	1,097
Deferred income	39,169	33,241
TOTAL LIABILITIES	1,779,082	1,565,282
EQUITY
Additional paid-in capital	1,330,444	1,062,473
Accumulated other comprehensive income (loss)	(24,642)	2,073
Accumulated dividends in excess of earnings	(376,002)	(278,548)
Total stockholders' equity	1,337,817	1,193,986
Noncontrolling interests	106,634	102,701
TOTAL EQUITY	1,444,451	1,296,687
TOTAL LIABILITIES AND EQUITY	3,223,533	2,861,969
Qualitytech, LP
Real Estate Assets
Land	130,605	105,541
Buildings, improvements and equipment	2,178,901	1,917,251
Less: Accumulated depreciation	(558,560)	(467,644)
Total real estate assets	1,750,946	1,555,148
Construction in progress	920,922	790,064
Real Estate Assets, net	2,671,868	2,345,212
Investments in unconsolidated entity	30,218
Operating lease right-of-use assets, net	57,141
Cash and cash equivalents	15,653	11,759
Rents and other receivables, net	81,181	55,093
Acquired intangibles, net	81,679	95,451
Deferred costs, net	52,363	45,096
Prepaid expenses	10,586	6,822
Goodwill	173,843	173,843
Assets held for sale		71,800
Other assets, net	49,001	56,893
TOTAL ASSETS	3,223,533	2,861,969
LIABILITIES
Unsecured credit facility, net	1,010,640	945,657
Senior notes, net of debt issuance costs	395,549	394,786
Finance leases and mortgage notes payable	46,876	4,674
Operating lease liabilities	64,416
Accounts payable and accrued liabilities	142,547	99,166
Dividends and distributions payable	34,500	29,633
Advance rents, security deposits and other liabilities	18,027	29,709
Derivative liabilities	26,609	2,970
Liabilities held for sale		24,349
Deferred income taxes	749	1,097
Deferred income	39,169	33,241
TOTAL LIABILITIES	1,779,082	1,565,282
EQUITY
Accumulated other comprehensive income (loss)	(27,465)	2,344
TOTAL EQUITY	1,444,451	1,296,687
TOTAL PARTNERS' CAPITAL	1,444,451	1,296,687
TOTAL LIABILITIES AND EQUITY	3,223,533	2,861,969
Series A Redeemable Perpetual Preferred
EQUITY
Cumulative redeemable perpetual preferred stock / units	103,212	103,212
Series A Redeemable Perpetual Preferred | Qualitytech, LP
EQUITY
Cumulative redeemable perpetual preferred stock / units	103,212	103,212
Series B Convertible Preferred Units
EQUITY
Cumulative redeemable perpetual preferred stock / units	304,223	304,265
Series B Convertible Preferred Units | Qualitytech, LP
EQUITY
Cumulative redeemable perpetual preferred stock / units	304,223	304,265
Common stock
EQUITY
Common stock / units	582	511
Common stock | Qualitytech, LP
EQUITY
Common stock / units	$ 1,064,481	$ 886,866

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Series A Redeemable Perpetual Preferred
Dividend rate (as a percent)	7.125%	7.125%
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, liquidation preference	$ 25	$ 25
Preferred stock, shares authorized	4,600,000	4,600,000
Preferred stock, shares issued	4,280,000	4,280,000
Preferred stock, shares outstanding	4,280,000	4,280,000
Series A Redeemable Perpetual Preferred | Qualitytech, LP
Dividend rate (as a percent)	7.125%	7.125%
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, liquidation preference	$ 25	$ 25
Preferred stock, shares authorized	4,600,000	4,600,000
Preferred stock, shares issued	4,280,000	4,280,000
Preferred stock, shares outstanding	4,280,000	4,280,000
Series B Convertible Preferred Units
Dividend rate (as a percent)	6.50%	6.50%
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, liquidation preference	$ 100	$ 100
Preferred stock, shares authorized	3,162,500	3,162,500
Preferred stock, shares issued	3,162,500	3,162,500
Preferred stock, shares outstanding	3,162,500	3,162,500
Series B Convertible Preferred Units | Qualitytech, LP
Dividend rate (as a percent)	6.50%	6.50%
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, liquidation preference	$ 100	$ 100
Preferred stock, shares authorized	3,162,500	3,162,500
Preferred stock, shares issued	3,162,500	3,162,500
Preferred stock, shares outstanding	3,162,500	3,162,500
Common stock
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	450,133,000	450,133,000
Common stock, shares issued	58,227,523	51,123,417
Common stock, shares outstanding	58,227,523	51,123,417
Common stock | Qualitytech, LP
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	450,133,000	450,133,000
Common stock, shares issued	64,901,157	57,799,035
Common stock, shares outstanding	64,901,157	57,799,035

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenues:
Rental	$ 465,123	$ 413,620	$ 379,787
Other	15,695	36,904	66,723
Total revenues	480,818	450,524	446,510
Operating Expenses:
Property operating costs	156,048	148,236	153,209
Real estate taxes and insurance	14,503	12,193	11,959
Depreciation and amortization	168,305	149,891	140,924
General and administrative	80,385	80,857	87,231
Transaction, integration and impairment costs	15,190	2,743	11,060
Restructuring		37,943
Total operating expenses	434,431	431,863	404,383
Gain on sale of real estate, net	14,769
Operating income	61,156	18,661	42,127
Other income and expenses:
Interest income	111	150	67
Interest expense	(26,593)	(28,749)	(30,523)
Debt restructuring costs	(1,523)	(605)	(19,992)
Other income (expense)	(50)
Equity in net loss of unconsolidated entity	(1,473)
Income (loss) before taxes	31,628	(10,543)	(8,321)
Tax benefit of taxable REIT subsidiaries	37	3,368	9,778
Net income (loss)	31,665	(7,175)	1,457
Net (income) loss attributable to noncontrolling interests	(374)	2,715	(175)
Net income (loss) attributable to QTS Realty Trust, Inc.	31,291	(4,460)	1,282
Preferred stock dividends	(28,180)	(16,666)
Net income (loss) attributable to common stockholders	$ 3,111	$ (21,126)	$ 1,282
Net income per share attributable to Class A common shares:
Basic (in dollars per share)	$ (0.09)	$ (0.44)	$ 0.01
Diluted (in dollars per share)	$ (0.09)	$ (0.44)	$ 0.01
Weighted average Class A common shares outstanding:
Basic (in shares)	54,836,801	50,432,590	48,380,964
Diluted (in shares)	54,836,801	50,432,590	55,855,683
Qualitytech, LP
Revenues:
Rental	$ 465,123	$ 413,620	$ 379,787
Other	15,695	36,904	66,723
Total revenues	480,818	450,524	446,510
Operating Expenses:
Property operating costs	156,048	148,236	153,209
Real estate taxes and insurance	14,503	12,193	11,959
Depreciation and amortization	168,305	149,891	140,924
General and administrative	80,385	80,857	87,231
Transaction, integration and impairment costs	15,190	2,743	11,060
Restructuring		37,943
Total operating expenses	434,431	431,863	404,383
Gain on sale of real estate, net	14,769
Operating income	61,156	18,661	42,127
Other income and expenses:
Interest income	111	150	67
Interest expense	(26,593)	(28,749)	(30,523)
Debt restructuring costs	(1,523)	(605)	(19,992)
Other income (expense)	(50)
Equity in net loss of unconsolidated entity	(1,473)
Income (loss) before taxes	31,628	(10,543)	(8,321)
Tax benefit of taxable REIT subsidiaries	37	3,368	9,778
Net income (loss)	31,665	(7,175)	1,457
Preferred stock dividends	(28,180)	(16,666)
Net income (loss) attributable to common stockholders	$ 3,485	$ (23,841)	$ 1,457

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Net income (loss)	$ 31,665	$ (7,175)	$ 1,457
Other comprehensive income (loss):
Foreign currency translation adjustment gain	34
Increase (decrease) in fair value of derivative contracts	(29,843)	895	1,449
Reclassification of other comprehensive income to utilities expense	749	0	0
Reclassification of other comprehensive income to interest expense	(1,031)	110
Comprehensive income (loss)	1,574	(6,170)	2,906
Comprehensive (income) loss attributable to noncontrolling interests	(169)	711	(349)
Comprehensive income (loss) attributable to QTS Realty Trust, Inc.	1,405	(5,459)	2,557
Qualitytech, LP
Net income (loss)	31,665	(7,175)	1,457
Other comprehensive income (loss):
Foreign currency translation adjustment gain	34
Increase (decrease) in fair value of derivative contracts	(29,843)	895	1,449
Reclassification of other comprehensive income to utilities expense	749
Reclassification of other comprehensive income to interest expense	(1,031)	110
Comprehensive income (loss)	$ 1,574	$ (6,170)	$ 2,906

CONSOLIDATED STATEMENTS OF EQUI

CONSOLIDATED STATEMENTS OF EQUITY - USD ($) $ in Thousands	Series B Convertible Preferred UnitsQualitytech, LPCommon stockLimited Partner	Series B Convertible Preferred UnitsQualitytech, LP	Series A Preferred StockQualitytech, LPPreferred stockLimited Partner	Series A Preferred StockQualitytech, LPCommon stockLimited Partner	Series A Preferred StockQualitytech, LP	Series A Preferred StockPreferred stock	Series A Preferred StockAccumulated dividends in excess of earnings	Series A Preferred StockTotal stockholders' Equity	Series A Preferred Stock	Series B Preferred StockQualitytech, LPPreferred stockLimited Partner	Series B Preferred StockQualitytech, LPCommon stockLimited Partner	Series B Preferred StockQualitytech, LP	Series B Preferred StockPreferred stock	Series B Preferred StockAccumulated dividends in excess of earnings	Series B Preferred StockTotal stockholders' Equity	Series B Preferred Stock	Qualitytech, LPPreferred stockLimited Partner	Qualitytech, LPCommon stockLimited Partner	Qualitytech, LPCommon stockGeneral Partner	Qualitytech, LPAccumulated other comprehensive income (loss)	Qualitytech, LP	Preferred stock	Common stock	Additional paid-in capital	Accumulated other comprehensive income (loss)	Accumulated dividends in excess of earnings	Total stockholders' Equity	Noncontrolling interests	Total
Beginning balance at Dec. 31, 2016																					$ 952,810		$ 478	$ 931,783		$ (97,793)	$ 834,468	$ 118,342	$ 952,810
Beginning balance, shares at Dec. 31, 2016																							47,831,000
Limited Partners' Capital, Beginning at Dec. 31, 2016																		$ 952,810
Limited Partners' Capital, Beginning balance, shares at Dec. 31, 2016																		54,628,000
Beginning balance, shares at Dec. 31, 2016																			1,000
Net share activity through equity award plan																		$ 1,022			1,022		$ 6	893			899	123	1,022
Net share activity through equity award plan, shares																		582,000					582,000
Stock Issued During Period, Shares, Conversion of Units																							253,000
Reclassification of noncontrolling interest upon conversion of partnership units to common stock																							$ 3	8,352			8,355	(8,355)
Increase (decrease) in fair value of derivative contracts																				$ 1,449	1,449				$ 1,283		1,283	166	1,449
Equity-based compensation expense																		$ 13,863			13,863			12,196			12,196	1,667	13,863
Proceeds net of fees from common equity offering																		$ 107,495			107,495		$ 20	95,952			95,972	11,523	107,495
Proceeds net of fees from common equity offering (in shares)																		2,036,000					2,036,000
Dividends declared to common stockholders																		$ (77,041)			(77,041)					(77,041)	(77,041)		(77,041)
Dividends declared to noncontrolling interests																												(10,399)	(10,399)
Partnership distributions																		(10,399)			(10,399)
Net income (loss)																		1,457			1,457					1,282	1,282	175	1,457
Ending balance at Dec. 31, 2017																				1,449	990,656		$ 507	1,049,176	1,283	(173,552)	877,414	113,242	990,656
Ending balance, shares at Dec. 31, 2017																							50,702,000
Limited Partners' Capital, Ending balance at Dec. 31, 2017																		$ 989,207
Limited Partners' Capital Ending balance, shares at Dec. 31, 2017																		57,246,000
Ending balance, shares at Dec. 31, 2017																			1,000
Net share activity through equity award plan																		$ (1,788)			(1,788)		$ 4	(2,717)			(2,713)	925	(1,788)
Net share activity through equity award plan, shares																		553,000					421,000
Increase (decrease) in fair value of derivative contracts																				895	895				790		790	105	895
Equity-based compensation expense																		$ 18,100			18,100			16,014			16,014	2,086	18,100
Proceeds net of fees from common equity offering			$ 103,212		$ 103,212	$ 103,212		$ 103,212	$ 103,212	$ 304,265		$ 304,265	$ 304,265		$ 304,265	$ 304,265
Proceeds net of fees from common equity offering (in shares)			4,280,000			4,280,000				3,163,000			3,163,000
Dividends declared on Preferred Stock																					(16,666)								(16,666)
Dividends declared on Preferred Units				$ (6,046)	(6,046)		$ (6,046)	(6,046)	(6,046)		$ (10,621)	$ (10,621)		$ (10,621)	(10,621)	(10,621)
Dividends declared to common stockholders																		(83,869)			(83,869)					(83,869)	(83,869)		(83,869)
Dividends declared to noncontrolling interests																												(10,942)	(10,942)
Partnership distributions																		(10,942)			(10,942)
Net income (loss)																		(7,175)			(7,175)					(4,460)	(4,460)	(2,715)	(7,175)
Ending balance at Dec. 31, 2018																				2,344	1,296,687	$ 407,477	$ 511	1,062,473	2,073	(278,548)	1,193,986	102,701	1,296,687
Ending balance, shares at Dec. 31, 2018																						7,443,000	51,123,000
Limited Partners' Capital, Ending balance at Dec. 31, 2018																	$ 407,477	$ 886,866
Limited Partners' Capital Ending balance, shares at Dec. 31, 2018																	7,443,000	57,799,000
Ending balance, shares at Dec. 31, 2018																			1,000
Partners' Capital, Ending Balance at Dec. 31, 2018																					1,296,687
Net cumulative effect upon ASC 842 adoption																		$ (1,813)			(1,813)					(1,813)	(1,813)		(1,813)
Net share activity through equity award plan																		$ 1,825			1,825		$ 3	1,816			1,819	6	1,825
Net share activity through equity award plan, shares																		270,000					273,000
Increase (decrease) in fair value of derivative contracts																				(29,843)	(29,843)				(26,745)		(26,745)	(3,098)	(29,843)
Foreign currency translation adjustments																				34	34				30		30	4	34
Equity-based compensation expense																		$ 16,413			16,413			14,651			14,651	1,762	16,413
Proceeds net of fees from settlement of forward shares																		$ 109,527			109,527		$ 28	102,854			102,882	6,645	109,527
Proceeds net of fees from settlement of forward shares (in shares)																		2,832,000					2,832,000
Adjustment to expenses net			$ (42)		(42)	$ (42)		(42)	(42)
Proceeds net of fees from common equity offering																		$ 158,663			158,663		$ 40	148,650			148,690	9,973	158,663
Proceeds net of fees from common equity offering (in shares)																		4,000,000					4,000,000
Dividends declared on Preferred Stock	$ (20,556)	$ (20,556)		$ (7,624)	$ (7,624)		$ (7,624)	$ (7,624)	$ (7,624)					$ (20,556)	$ (20,556)	$ (20,556)					(28,180)								(28,180)
Dividends declared to common stockholders																		$ (98,752)			(98,752)					(98,752)	(98,752)		(98,752)
Dividends declared to noncontrolling interests																												(11,733)	(11,733)
Partnership distributions																		(11,733)			(11,733)
Net income (loss)																		31,665			31,665					31,291	31,291	374	31,665
Ending balance at Dec. 31, 2019																				$ (27,465)	1,444,451	$ 407,435	$ 582	$ 1,330,444	$ (24,642)	$ (376,002)	$ 1,337,817	$ 106,634	$ 1,444,451
Ending balance, shares at Dec. 31, 2019																						7,443,000	58,228,000
Limited Partners' Capital, Ending balance at Dec. 31, 2019																	$ 407,435	$ 1,064,481
Limited Partners' Capital Ending balance, shares at Dec. 31, 2019																	7,443,000	64,901,000
Ending balance, shares at Dec. 31, 2019																			1,000
Partners' Capital, Ending Balance at Dec. 31, 2019																					$ 1,444,451

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOW - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash flow from operating activities:
Net income (loss)	$ (3,606)	$ 31,665	$ (7,175)	$ 1,457
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization		160,528	143,354	136,585
Amortization of above and below market leases		187	465	865
Amortization of deferred loan costs		3,877	3,856	3,640
Amortization of senior notes discount				229
Distributions from unconsolidated entity		3,280
Equity in (earnings) loss of unconsolidated entity		1,473
Loss on extinguishment of debt				19,912
Equity-based compensation expense		16,412	14,972	13,863
Bad debt expense (recoveries)		2,406	(2,275)	3,519
Write off of deferred loan costs		1,532	605	80
Deferred tax expense (benefit)		(348)	(2,970)	(10,742)
(Gain) loss on sale of assets, net		(14,769)	6,994
Integration, impairment & restructuring costs		11,462	19,575	9,027
Foreign currency remeasurement (gain) loss		50
Changes in operating assets and liabilities
Rents and other receivables, net		(27,234)	(6,495)	(12,881)
Prepaid expenses		(3,406)	(3,063)	755
Due to/from affiliates, net		9,284
Other assets		35	4,518	282
Accounts payable and accrued liabilities		2,973	8,573	(5,071)
Advance rents, security deposits and other liabilities		(5,845)	2,069	5,491
Deferred income		5,928	8,270	3,312
Net cash provided by operating activities		199,490	191,273	170,323
Cash flow from investing activities:
Proceeds from sale of property		54,427	2,779
Acquisitions, net of cash acquired		(76,383)	(117,029)	(127,038)
Investments in unconsolidated entity		4,144
Additions to property and equipment		(361,160)	(484,303)	(307,314)
Net cash used in investing activities		(387,260)	(598,553)	(434,352)
Cash flow from financing activities:
Credit facility proceeds		399,028	483,000	888,000
Credit facility repayments		(334,000)	(362,000)	(696,000)
Debt Proceeds				1,920
5.75% Senior Notes Repayment				(300,000)
4.75% Notes Issuance				400,000
Payment of debt extinguishment costs				(13,218)
Payment of deferred financing costs		(5,130)	(3,964)	(10,862)
Payment of preferred stock dividends		(28,180)	(10,728)
Payment of common stock dividends		(94,085)	(82,579)	(74,592)
Distribution to noncontrolling interests		(11,533)	(10,759)	(10,289)
Proceeds from exercise of stock options		3,857	246	4,972
Payment of tax withholdings related to equity based awards		(3,900)	(2,205)	(4,725)
Principal payments on finance lease obligations		(2,855)	(7,626)	(12,224)
Mortgage principal debt repayments		(65)	(66)	(54)
Preferred stock issuance proceeds, net of costs			407,477
Common stock issuance proceeds, net of costs		268,259		107,549
Net cash provided by financing activities		191,396	410,796	262,692
Effect of foreign currency exchange rates on cash and cash equivalents		268
Net change in cash and cash equivalents		3,894	3,516	(1,337)
Cash and cash equivalents, beginning of period		11,759	8,243	9,580
Cash and cash equivalents, end of period	15,653	15,653	11,759	8,243
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION
Cash paid for interest (excluding deferred financing costs and amounts capitalized)		56,023	51,380	44,357
Noncash investing and financing activities:
Accrued capital additions		92,206	76,890	75,965
Net increase (decrease) in derivative liabilities related to change in fair value of derivative contracts		(28,952)	895
Equity received in unconsolidated entity in exchange for real estate assets		25,280
Accrued preferred stock dividends		5,938	5,938
Accrued deferred financing costs			76	458
Accrued equity issuance costs		30	115	25
Acquisitions, net of cash acquired:
Land	1,743	1,743		9,363
Buildings, improvements and equipment	8,640	8,640	445	14,341
Construction in Progress	61,514	61,514	114,283	103,334
Rents and other receivables, net	1,239	1,239
Acquired intangibles, net	2,628	2,628	2,301
Deferred costs	906	906
Prepaid expenses	359	359
Other assets	128	128
Accounts payable and accrued liabilities	(52)	(52)
Advance rents, security deposits and other liabilities	(722)	(722)
Total acquisitions, net of cash acquired		76,383	117,029	127,038
Dulles, Virginia
Cash flow from financing activities:
Principal payments on finance lease obligations				(17,785)
Qualitytech, LP
Cash flow from operating activities:
Net income (loss)	(3,606)	31,665	(7,175)	1,457
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization		160,528	143,354	136,585
Amortization of above and below market leases		187	465	865
Amortization of deferred loan costs		3,877	3,856	3,640
Amortization of senior notes discount				229
Distributions from unconsolidated entity		3,280
Equity in (earnings) loss of unconsolidated entity		1,473
Loss on extinguishment of debt				19,912
Equity-based compensation expense		16,412	14,972	13,863
Bad debt expense (recoveries)		2,406	(2,275)	3,519
Write off of deferred loan costs		1,532	605	80
Deferred tax expense (benefit)		(348)	(2,970)	(10,742)
(Gain) loss on sale of assets, net		(14,769)	6,994
Integration, impairment & restructuring costs		11,462	19,575	9,027
Foreign currency remeasurement (gain) loss		50
Changes in operating assets and liabilities
Rents and other receivables, net		(27,234)	(6,495)	(12,881)
Prepaid expenses		(3,406)	(3,063)	755
Due to/from affiliates, net		9,284
Other assets		35	4,518	282
Accounts payable and accrued liabilities		2,973	8,573	(5,071)
Advance rents, security deposits and other liabilities		(5,845)	2,069	5,491
Deferred income		5,928	8,270	3,312
Net cash provided by operating activities		199,490	191,273	170,323
Cash flow from investing activities:
Proceeds from sale of property		54,427	2,779
Acquisitions, net of cash acquired		(76,383)	(117,029)	(127,038)
Investments in unconsolidated entity		4,144
Additions to property and equipment		(361,160)	(484,303)	(307,314)
Net cash used in investing activities		(387,260)	(598,553)	(434,352)
Cash flow from financing activities:
Credit facility proceeds		399,028	483,000	888,000
Credit facility repayments		(334,000)	(362,000)	(696,000)
Debt Proceeds				1,920
5.75% Senior Notes Repayment				(300,000)
4.75% Notes Issuance				400,000
Payment of debt extinguishment costs				(13,218)
Payment of deferred financing costs		(5,130)	(3,964)	(10,862)
Payment of preferred stock dividends		(28,180)	(10,728)
Payment of cash dividends		(94,085)	(82,579)	(74,592)
Partnership distributions		(11,533)	(10,759)	(10,289)
Proceeds from exercise of stock options		3,857	246	4,972
Payment of tax withholdings related to equity based awards		(3,900)	(2,205)	(4,725)
Principal payments on finance lease obligations		(2,855)	(7,626)	(12,224)
Mortgage principal debt repayments		(65)	(66)	(54)
Preferred stock issuance proceeds, net of costs			407,477
Common stock issuance proceeds, net of costs		268,259		107,549
Net cash provided by financing activities		191,396	410,796	262,692
Effect of foreign currency exchange rates on cash and cash equivalents		268
Net change in cash and cash equivalents		3,894	3,516	(1,337)
Cash and cash equivalents, beginning of period		11,759	8,243	9,580
Cash and cash equivalents, end of period	15,653	15,653	11,759	8,243
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION
Cash paid for interest (excluding deferred financing costs and amounts capitalized)		56,023	51,380	44,357
Noncash investing and financing activities:
Accrued capital additions		92,206	76,890	75,965
Net increase (decrease) in derivative liabilities related to change in fair value of derivative contracts		(28,952)	895
Equity received in unconsolidated entity in exchange for real estate assets		25,280
Accrued preferred stock dividends		5,938	5,938
Accrued deferred financing costs			76	458
Accrued equity issuance costs		30	115	25
Acquisitions, net of cash acquired:
Land	1,743	1,743		9,363
Buildings, improvements and equipment	8,640	8,640	445	14,341
Construction in Progress	61,514	61,514	114,283	103,334
Rents and other receivables, net	1,239	1,239
Acquired intangibles, net	2,628	2,628	2,301
Deferred costs	906	906
Prepaid expenses	359	359
Other assets	128	128
Accounts payable and accrued liabilities	(52)	(52)
Advance rents, security deposits and other liabilities	$ (722)	(722)
Total acquisitions, net of cash acquired		$ 76,383	$ 117,029	127,038
Qualitytech, LP | Dulles, Virginia
Cash flow from financing activities:
Principal payments on finance lease obligations				$ (17,785)

Description of Business

Description of Business	12 Months Ended
	Dec. 31, 2019
Description of Business [Abstract]
Description of Business	1. 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, 2019 our portfolio consisted of 24 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, 2019, QTS owned approximately 89.7% of the interests in the Operating Partnership. Substantially all of QTS’ assets are held by, and 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 affairs, subject to certain limited approval and voting rights of the limited partners. QTS’ board of directors manages the Company’s business and affairs.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2019
Summary of Significant Accounting Policies [Abstract]
Summary of Significant Accounting Policies	2. 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. ​ The accompanying financial statements are presented for both QTS Realty Trust, Inc. and QualityTech, LP. 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 ASC Topic 810 Consolidation ​ 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. ​ The Company believes, therefore, that providing one set of notes for the financial statements of QTS and the Operating Partnership provides the following benefits: ​ ● enhances investors’ understanding of QTS and the Operating Partnership by enabling investors to view the business as a whole in the same manner as management views and operates the business; ● eliminates duplicative disclosure and provides a more streamlined and readable presentation since a substantial portion of the disclosure applies to both QTS and the Operating Partnership; and ● creates time and cost efficiencies through the preparation of one set of notes instead of two separate sets of notes. ​ In addition, in light of these combined notes, the Company believes it is important for investors to understand the few differences between QTS and the Operating Partnership in the context of how QTS and the Operating Partnership operate as a consolidated company. With respect to balance sheets, the presentation of stockholders’ equity and partners’ capital are the main areas of difference between the consolidated balance sheets of QTS and those of the Operating Partnership. On the Operating Partnership’s consolidated balance sheets, partners’ capital includes preferred partnership units and common partnership units that are owned by QTS and other partners as well as accumulated other comprehensive income (loss). On QTS’ consolidated balance sheets, stockholders’ equity includes preferred stock, common stock, additional paid in capital, accumulated other comprehensive income (loss) and accumulated dividends in excess of earnings. The remaining equity reflected on QTS’s consolidated balance sheet is the portion of net assets that are retained by partners other than QTS, referred to as noncontrolling interests. With respect to statements of operations, the primary difference in QTS' Statements of Operations and Statements of Comprehensive Income (Loss) is that for net income (loss), QTS retains its proportionate share of the net income (loss) based on its ownership of the Operating Partnership, with the remaining balance being retained by the Operating Partnership. These combined notes refer to actions or holdings as being actions or holdings of “the Company.” Although the Operating Partnership is generally the entity that enters into contracts, holds assets and issues debt, management believes that these general references to “the Company” in this context is appropriate because the business is one enterprise operated through the Operating Partnership. ​ As discussed above, QTS owns no operating assets and has no operations independent of the Operating Partnership and its subsidiaries. Also, the Operating Partnership owns no operating assets and has no operations independent of its subsidiaries. Obligations under the 4.750% Senior Notes due 2025 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 4.750% Senior Notes due 2025) or any subsidiary guarantor. The indenture governing the 4.750% Senior Notes due 2025 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 investment accounting. This includes the operating results of the Operating Partnership for all periods presented. ​ Use of Estimates ​ Principles of Consolidation the accounts of QualityTech, LP and its 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 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, 2019, 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 aggregate investment, which was approximately $30.2 million as of December 31, 2019. ​ Reclassifications ​ Real Estate Assets $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. For the year ended December 31, 2017, depreciation expense related to real estate assets and non-real estate assets was $90.1 million and $14.2 million, respectively, for a total of $104.3 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 depreciated over its estimated useful life. Capitalization of such costs, excluding interest, aggregated to $17.8 million, $17.4 million and $12.7 million for the years ended December 31, 2019, 2018 and 2017 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 $33.2 million, $26.8 million and $14.3 million for the years ended December 31, 2019, 2018 and 2017, respectively. ​ Acquisitions and Sales Business Combinations ​ 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. ​ Other acquired intangible assets, which includes platform, above or below market leases, and trade name intangibles, are amortized on a straight-line basis over their respective expected lives. Above or below market leases are amortized 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. The expense associated with trade name intangibles is accounted for as real estate amortization expense, whereas the expense associated with the amortization of platform intangibles is accounted for as non-real estate amortization expense. ​ We account for the sale of assets to non-customers under Financial Accounting Standards Board (“FASB”) Accounting Standards Update (“ASU”) No. 2017-05, Other Income—Gains and Losses from the Derecognition of Nonfinancial Assets 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 ​ 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, 2019, 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, 2019. ​ Assets Held for Sale ​ Cash and Cash Equivalents 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 financing costs and 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 $3.9 million, $3.9 million and $3.6 million for the years ended December 31, 2019, 2018 and 2017, respectively. 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 year additional term loan, increased capacity of the revolving facility, extended maturity dates as well as decreased the interest rates. During the year ended December 31, 2018, we wrote off unamortized financing costs of $0.6 million in connection with the modification of our unsecured credit facility in November 2018 whereby we decreased the interest rates, modified and/or eliminated certain covenants and extended the term for an additional year. During the year ended December 31, 2017, we wrote off unamortized financing costs of $5.2 million primarily in connection with the replacement of our $300 million 5.875% senior notes with the $400 million of 4.750% notes. ​ Deferred financing costs presented as assets on the balance sheets related to revolving debt arrangements, net of accumulated amortization are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ ​ December 31, (dollars in thousands) 2019 2018 ​ ​ ​ ​ ​ ​ ​ Deferred financing costs ​ $ 13,776 ​ $ 11,530 Accumulated amortization ​ ​ (5,743) ​ ​ (3,859) Deferred financing costs, net ​ $ 8,033 ​ $ 7,671 ​ 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: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ ​ December 31, (dollars in thousands) 2019 2018 ​ ​ ​ ​ ​ ​ ​ Deferred financing costs ​ $ 15,777 ​ $ 14,501 Accumulated amortization ​ ​ (4,937) ​ ​ (2,944) Deferred financing costs, net ​ $ 10,840 ​ $ 11,557 ​ 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 Revenue from Contracts with Customers leasing costs totaled $24.2 million, $21.3 million and $18.5 million for the years ended December 31, 2019, 2018 and 2017, respectively. Deferred leasing costs, net of accumulated amortization are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ December 31, (dollars in thousands) 2019 2018 ​ ​ ​ ​ ​ ​ ​ Deferred leasing costs ​ $ 77,178 ​ $ 63,018 Accumulated amortization ​ ​ (32,848) ​ ​ (25,593) Deferred leasing costs, net ​ $ 44,330 ​ $ 37,425 ​ Revenue Recognition – Leases Revenue from Contracts with Customers ​ 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 $38.7 million and $29.7 million as of December 31, 2019 and December 31, 2018, respectively. ​ Rental revenue also includes amortization of set-up fees which are amortized over the term of the respective lease as discussed below. ​ 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 of the statements of operations. ​ Other Revenue ​ Other revenue primarily consists of revenue from our cloud and managed service offerings as well as revenue earned from partner channel, management and development fees. We, through our TRS, may provide both our cloud product and use of our managed services to our customers on an individual or combined basis. In both our cloud and managed services offerings 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 cloud and 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 affiliate properties as well as third parties. Management fee revenue is earned based on a contractual percentage of unconsolidated affiliate 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 ​ Advance Rents and Security Deposits – ​ Deferred Income – deferred income liability which amortizes into rental revenue over the term of the related lease on a straight-line basis. Deferred income was $39.2 million, $33.2 million and $25.3 million as of December 31, 2019, 2018 and 2017, respectively. Additionally, $15.2 million, $12.5 million and $10.7 million of deferred income was amortized into revenue for the years ended December 31, 2019, 2018 and 2017, respectively. ​ Foreign Currency - ​ Equity-based Compensation ​ Segment Information ​ Customer Concentrations ​ As of December 31, 2019, five of our customers exceeded 5% of trade accounts receivable. In aggregate, these five customers accounted for 30% of trade accounts receivable. None of these customers individually exceeded 10% of total accounts receivable. ​ 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, as 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 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 federal income and excise tax liability. ​ Fair Value Measurements Fair Value Measurement ​ 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, 2019, 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 ​ Revenue from Contracts with Customers ​ In May 2014, the FASB issued guidance codified in ASC Topic 606, Revenue from Contracts with Customers Revenue Recognition ​ Leases ​ In February 2016, and further amended in 2018, the FASB issued ASC Topic 842, Leases Leases ​ We adopted ASC Topic 842 effective January 1, 2019 using the modified retrospective approach, which applied the provisions of the new guidance at the effective date without adjusting comparative periods presented. We elected a package of practical expedients permitted under the transition guidance within the new standard which allowed us to not reassess (i) whether expired or existing contracts contain a lease under the new standard, (ii) the lease classification for existing leases or (iii) whether previously-capitalized initial direct costs would qualify for capitalization under the new standard. We did not elect the hindsight practical expedient which permits entities to use hindsight in determining the lease term and assessing impairment. ​ The adoption of ASC Topic 842 impacted our consolidated balance sheets with the recognition of existing operating leases as lessee resulting in $62.9 million of ROU assets and $70.7 million of lease liabilities recorded as of January 1, 2019. We also recognized a $1.8 million cumulative effect adjustment to retained earnings. The adjustment to retained earnings was due to an impairment of certain ROU assets associated with vacant office space for which we are a lessee and assumed in a prior acquisition. See the table below for the impact of adoption of the lease standard on our consolidated balance sheets as of January 1, 2019 (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As Previously ​ New Lease Standard ​ ​ ​ ​ Reported ​ Adjustment ​ As Adjusted Operating lease right-of-use assets ​ $ — ​ $ 62,922 ​ $ 62,922 Operating lease liabilities ​ ​ — ​ ​ 70,657 ​ ​ 70,657 Deferred rent payable ​ ​ 5,922 ​ ​ (5,922) ​ ​ — ​ As lessor, accounting for our leases remained largely unchanged from ASC Topic 840. The new lease standard more narrowly defines initial direct costs as only costs that are incremental to origination of a lease (i.e. costs that would not have been incurred had the lease not been obtained). We did not historically capitalize non-incremental costs, therefore this change did not have an impact on the accounting for initial direct costs in the consolidated financial statements. ​ Additionally, from a lessor perspective, we elected a practical expedient which allows lessors to combine nonlease components with the related lease components if both the timing and pattern of transfer are the same for the nonlease component(s) and related lease component, and the lease component would be classified as an operating lease. 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. Lessors are permitted to apply the practical expedient to all existing leases on a retrospective or prospective basis. We elected the practical expedient to combine our lease and nonlease components that meet the defined criteria and account for the combined lease component under ASC Topic 842. ​ New Accounting Pronouncements ​ In August 2018, the FASB issued ASU 2018-13, Fair Value Measurement ​ In August 2018, the FASB issued ASU 2018-15, Intangibles – Goodwill and Other – Internal-Use Software ( ​ In June 2016, the FASB issued ASU

Acquisitions and Sales

Acquisitions and Sales	12 Months Ended
	Dec. 31, 2019
Acquisitions and Sales [Abstract]
Acquisitions and Sales	3. Acquisitions and Sales ​ (All references to square footage, acres and megawatts are unaudited) ​ 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. The two facilities, in Groningen and Eemshaven, have 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 is 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 ​ ​ ​ Land Acquisitions ​ In April 2019, we completed the acquisition of approximately 4 acres of land for our Atlanta (DC-2) facility for approximately $2.2 million. In July 2019, we completed the acquisition of approximately 28 acres of land in Ashburn, Virginia for approximately $22.4 million. In November 2019, we completed the acquisition of approximately 75 acres of land in Richmond, Virginia for approximately $7.0 million. These acquisitions were accounted for as asset acquisitions and are included within the “Construction in Progress” line item of the consolidated balance sheets. ​ During 2018, we completed multiple acquisitions of land in Manassas, Virginia totaling 118 acres for approximately $37.0 million. A portion of the land was used to support the construction of the Manassas data center that we contributed to an unconsolidated entity subsequent to December 31, 2018. These acquisitions were accounted for as asset acquisitions. The land acquired in the Manassas purchases, as well as subsequent costs for construction in progress, were included within the “Construction in Progress” line item of the consolidated balance sheets. ​ In October 2018, we completed the acquisition of approximately 55 acres of land in Atlanta, Georgia adjacent to our existing Atlanta (DC-1) (formerly known as Atlanta-Metro) mega data center for approximately $80.1 million. The acquisition was accounted for as an asset acquisition, with the majority of the purchase price 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 .

Acquired Intangible Assets and

Acquired Intangible Assets and Liabilities	12 Months Ended
	Dec. 31, 2019
Acquired Intangible Assets and Liabilities [Abstract]
Acquired Intangibles Assets and Liabilities	4. Acquired Intangible Assets and Liabilities ​ Summarized below are the carrying values for the major classes of intangible assets and liabilities (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2019 ​ December 31, 2018 ​ Useful Lives Gross Accumulated Net Carrying Gross Accumulated Net Carrying Customer Relationships ​ 12 years ​ $ 95,705 ​ $ (36,411) ​ $ 59,294 ​ $ 95,705 ​ $ (28,461) ​ $ 67,244 In-Place Leases ​ 0.5 to 10 years ​ ​ 34,588 ​ ​ (22,522) ​ ​ 12,066 ​ ​ 32,066 ​ ​ (17,670) ​ ​ 14,396 Solar Power Agreement (1) ​ 17 years ​ ​ 13,747 ​ ​ (4,448) ​ ​ 9,299 ​ ​ 13,747 ​ ​ (3,639) ​ ​ 10,108 Acquired Favorable Leases ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Acquired below market leases - as Lessee ​ 46 years ​ ​ — ​ ​ — ​ ​ — ​ ​ 2,301 ​ ​ — ​ ​ 2,301 Acquired above market leases - as Lessor ​ 0.5 to 8 years ​ ​ 5,035 ​ ​ (4,015) ​ ​ 1,020 ​ ​ 4,649 ​ ​ (3,247) ​ ​ 1,402 Total Intangible Assets ​ ​ ​ $ 149,075 ​ $ (67,396) ​ $ 81,679 ​ $ 148,468 ​ $ (53,017) ​ $ 95,451 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Solar Power Agreement (1) ​ 17 years ​ ​ 13,747 ​ ​ (4,448) ​ ​ 9,299 ​ ​ 13,747 ​ ​ (3,639) ​ ​ 10,108 Acquired Unfavorable Leases ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Acquired below market leases - as Lessor ​ 3 to 4 years ​ ​ 1,092 ​ ​ (967) ​ ​ 125 ​ ​ 809 ​ ​ (611) ​ ​ 198 Acquired above market leases - as Lessee ​ 11 to 12 years ​ ​ 2,453 ​ ​ (983) ​ ​ 1,470 ​ ​ 2,453 ​ ​ (767) ​ ​ 1,686 Total Intangible Liabilities (2) ​ ​ ​ $ 17,292 ​ $ (6,398) ​ $ 10,894 ​ $ 17,009 ​ $ (5,017) ​ $ 11,992 (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 $0.2 million, $0.5 million, and $0.9 million for the years ended December 31, 2019, 2018 and 2017, 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 Decrease ​ Net Rental Expense Decrease 2020 $ 659 ​ $ (216) 2021 ​ 154 ​ ​ (216) 2022 ​ 52 ​ ​ (216) 2023 ​ 24 ​ ​ (216) 2024 ​ 6 ​ ​ (216) Thereafter ​ — ​ ​ (390) Total $ 895 ​ $ (1,470) ​ Net amortization of all other identified intangible assets and liabilities was $13.2 million, $15.0 million and $18.2 million for the years ended December 31, 2019, 2018 and 2017, 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): ​ ​ ​ ​ ​ ​ ​ 2020 ​ ​ ​ $ 12,100 2021 ​ ​ ​ ​ 10,593 2022 ​ ​ ​ ​ 10,073 2023 ​ ​ ​ ​ 10,070 2024 ​ ​ ​ ​ 8,953 Thereafter ​ ​ ​ ​ 19,571 Total ​ ​ ​ $ 71,360 ​

Real Estate Assets and Construc

Real Estate Assets and Construction in Progress	12 Months Ended
	Dec. 31, 2019
Real Estate Assets and Construction in Progress [Abstract]
Real Estate Assets and Construction in Progress	5 . Real Estate Assets and Construction in Progress ​ The following is a summary of our cost of owned or leased properties as of December 31, 2019 and 2018 (in thousands): ​ As of December 31, 2019: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Property Location Land Buildings and Improvements Construction 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) ​ ​ — ​ ​ 82,813 ​ ​ 666 ​ ​ 83,479 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) ​ ​ — ​ ​ 2,412 ​ ​ 31,840 ​ ​ 34,252 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 megascale 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 those subject to finance leases. (5) Consists of Miami, FL; Lenexa, KS; and Overland Park, KS facilities. ​ As of December 31, 2018: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Property Location Land Buildings and Construction Total Cost Atlanta, Georgia Campus( 1) ​ $ 20,416 ​ $ 493,446 ​ $ 88,253 ​ $ 602,115 Irving, Texas ​ ​ 8,606 ​ ​ 345,615 ​ ​ 99,445 ​ ​ 453,666 Richmond, Virginia ​ ​ 2,180 ​ ​ 253,098 ​ ​ 67,932 ​ ​ 323,210 Chicago, Illinois ​ ​ 9,400 ​ ​ 130,150 ​ ​ 133,095 ​ ​ 272,645 Ashburn, Virginia (2) ​ ​ 17,325 ​ ​ 63,245 ​ ​ 184,951 ​ ​ 265,521 Suwanee, Georgia (Atlanta-Suwanee) ​ ​ 3,521 ​ ​ 166,298 ​ ​ 3,188 ​ ​ 173,007 Piscataway, New Jersey ​ ​ 7,466 ​ ​ 97,806 ​ ​ 33,472 ​ ​ 138,744 Manassas, Virginia (2) (6) ​ ​ — ​ ​ — ​ ​ 45,194 ​ ​ 45,194 Santa Clara, California (3) ​ ​ — ​ ​ 98,548 ​ ​ 7,600 ​ ​ 106,148 Dulles, Virginia ​ ​ 3,154 ​ ​ 72,435 ​ ​ 3,852 ​ ​ 79,441 Fort Worth, Texas ​ ​ 9,079 ​ ​ 18,623 ​ ​ 43,715 ​ ​ 71,417 Sacramento, California ​ ​ 1,481 ​ ​ 64,874 ​ ​ 92 ​ ​ 66,447 Princeton, New Jersey ​ ​ 20,700 ​ ​ 34,046 ​ ​ 431 ​ ​ 55,177 Leased facilities (4) ​ ​ — ​ ​ 43,347 ​ ​ 9,334 ​ ​ 52,681 Hillsboro, Oregon (2) ​ ​ — ​ ​ — ​ ​ 39,835 ​ ​ 39,835 Phoenix, Arizona (2) ​ ​ — ​ ​ — ​ ​ 29,562 ​ ​ 29,562 Other (5) ​ ​ 2,213 ​ ​ 35,720 ​ ​ 113 ​ ​ 38,046 ​ ​ $ 105,541 ​ ​ 1,917,251 ​ ​ 790,064 ​ $ 2,812,856 (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 megascale 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 10 facilities. All facilities are leased, including those subject to finance leases. (5) Consists of Miami, FL; Lenexa, KS; Overland Park, KS; and Duluth, GA facilities. (6) Excludes $71.0 million of construction in progress included within the “Assets held for sale” line item of the consolidated balance sheets.

Leases

Leases	12 Months Ended
	Dec. 31, 2019
Leases [Abstract]
Leases	6. 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 the adoption of ASC Topic 842 effective January 1, 2019. See ‘Note 2’ for further details on recently adopted accounting standards. ​ 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 one to eighteen years . Our finance lease associated with the data center includes multiple extension option periods, some of which were included in the lease term as we are reasonably certain to exercise those extension options. Our other finance leases typically do not have options to extend the initial lease term. Finance lease assets are included within the “Buildings, improvements and equipment” line item of the consolidated balance sheets and finance lease liabilities are included within “Finance leases and mortgage notes payable” line item of the consolidated balance sheets. ​ 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 four to seven years . We have options to extend the initial lease term on nearly all of these leases. Additionally, we have one ground lease for our Santa Clara property that is considered an operating lease which is scheduled to expire in 2052. ​ Components of lease expense were as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ Year Ended ​ December 31, 2019 Finance lease cost: ​ ​ ​ Amortization of assets ​ $ 3,535 Interest on lease liabilities ​ ​ 1,693 Operating lease expense: ​ ​ ​ Operating lease cost ​ ​ 9,102 Variable lease cost ​ ​ 1,109 Sublease income ​ ​ (187) Total lease costs ​ $ 15,252 ​ Supplemental balance sheet information related to leases was as follows (in thousands, except lease term and discount rate): ​ ​ ​ ​ ​ ​ ​ December 31, ​ 2019 Operating leases: ​ ​ ​ Operating lease right-of-use assets ​ $ 57,141 Operating lease liabilities ​ ​ 64,416 Finance leases: ​ ​ ​ Property and equipment, at cost ​ ​ 50,437 Accumulated amortization ​ ​ (4,830) Property and equipment, net ​ $ 45,607 Finance lease liabilities ​ $ 45,141 ​ ​ ​ ​ Weighted average remaining lease term (in years): ​ ​ ​ Operating leases ​ ​ 13.7 Finance leases ​ ​ 11.4 ​ ​ ​ ​ Weighted average discount rate: ​ ​ ​ Operating leases ​ ​ 5.1% Finance leases ​ ​ 4.3% ​ Supplemental cash flow and other information related to leases was as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ Year Ended ​ December 31, 2019 Cash paid for amounts included in the measurement of lease liabilities: ​ ​ ​ Operating cash flows for operating leases ​ $ 9,834 Operating cash flows for finance leases ​ $ 1,704 Financing cash flows for finance leases ​ $ 2,855 ​ Maturities of lease liabilities, which exclude variable rent payments, are as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2019 ​ Operating Leases Finance Leases 2020 $ 9,589 ​ $ 4,493 2021 ​ 9,818 ​ ​ 4,514 2022 ​ 10,266 ​ ​ 4,639 2023 ​ 10,393 ​ ​ 4,776 2024 ​ 8,317 ​ ​ 4,918 Thereafter ​ 48,908 ​ ​ 34,990 Total Lease Payments $ 97,291 ​ $ 58,330 Less: Imputed Interest ​ 32,875 ​ ​ 13,189 Total Lease Obligations $ 64,416 ​ $ 45,141 ​ 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, ​ 2019 2018 Lease revenue: ​ ​ ​ ​ ​ ​ Minimum lease revenue ​ $ 409,157 ​ $ 367,388 Variable lease revenue (primarily recoveries from customers) ​ ​ 55,966 ​ ​ 46,232 Total lease revenue ​ $ 465,123 ​ $ 413,620 ​

Investments in Unconsolidated E

Investments in Unconsolidated Entity	12 Months Ended
	Dec. 31, 2019
Investments in Unconsolidated Entity [Abstract]
Investments in Unconsolidated Entity	7. Investments in Unconsolidated Entity ​ During the three months ended March 31, 2019, QTS formed an unconsolidated entity with Alinda Capital Partners (“Alinda”), an infrastructure investment firm. QTS 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 $30.2 million as of December 31, 2019. QTS and Alinda 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, 2019 the total assets of the entity were $127.8 million and the total debt outstanding, net of deferred financing costs, was $68.2 million. ​ 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 affiliate and its underlying equity as reflected in the unconsolidated affiliate’s financial statements generally result from costs of our investment that are not reflected on the unconsolidated affiliate’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, 2019
Debt [Abstract]
Debt	8. Debt ​ Below is a listing of our outstanding debt, including finance leases, as of December 31, 2019 and 2018 (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted Average ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Coupon Interest Rate at ​ Maturities as of ​ December 31, ​ December 31, ​ December 31, 2019 (1) December 31, 2019 2019 2018 Unsecured Credit Facility ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Revolving Credit Facility ​ 2.71% ​ December 17, 2023 ​ $ 317,028 ​ $ 252,000 Term Loan I ​ 3.16% ​ December 17, 2024 ​ ​ 225,000 ​ ​ 350,000 Term Loan II ​ 3.19% ​ April 27, 2025 ​ ​ 225,000 ​ ​ 350,000 Term Loan III ​ 3.19% ​ October 18, 2026 ​ ​ 250,000 ​ ​ — Senior Notes ​ 4.75% ​ November 15, 2025 ​ ​ 400,000 ​ ​ 400,000 Lenexa Mortgage ​ 4.10% ​ May 1, 2022 ​ ​ 1,736 ​ ​ 1,801 Finance Leases ​ 4.35% ​ 2021 - 2038 ​ ​ 45,140 ​ ​ 2,873 ​ ​ 3.54% ​ ​ ​ ​ 1,463,904 ​ ​ 1,356,674 Less net debt issuance costs ​ ​ ​ ​ ​ ​ (10,839) ​ ​ (11,557) Total outstanding debt, net ​ ​ ​ ​ ​ $ 1,453,065 ​ $ 1,345,117 (1) The coupon interest rates associated with Term Loans I - II incorporate the effects of our interest rate swaps in effect as of December 31, 2019. ​ Credit Facilities, Senior Notes and Mortgage Notes Payable ​ (a) Unsecured Credit Facility ​ 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. ​ The Company’s 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, 2019, the Company was in compliance with all of its covenants. ​ As of December 31, 2019, the Company had outstanding $1,017 million of indebtedness under the unsecured credit facility, consisting of $317 million of outstanding borrowings under the unsecured revolving credit facility and $700 million outstanding under the term loans, exclusive of net debt issuance costs of $6.4 million. In connection with the unsecured credit facility, as of December 31, 2019, the Company had letters of credit outstanding aggregating to $4.0 million. As of December 31, 2019, the weighted average interest rate for amounts outstanding under the unsecured credit facility, including the effects of interest rate swaps, was 3.03%. ​ The Company has also entered into certain interest rate swap agreements. See Note 10 – ‘Derivative Instruments’ for additional details. ​ (b) Senior Notes ​ The Senior Notes are unconditionally guaranteed, jointly and severally, on a senior unsecured basis by all of the Operating Partnership’s existing subsidiaries (other than 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 Senior Notes. QTS Realty Trust, Inc. does not guarantee the Senior Notes and will not be required to guarantee the Senior Notes except under certain circumstances. The offering was conducted pursuant to Rule 144A of the Securities Act of 1933, as amended, and the Senior Notes were issued pursuant to an indenture, dated as of November 8, 2017, among QTS, the Issuers, the guarantors named therein, and Deutsche Bank Trust Company Americas, as trustee. ​ The annual remaining principal payment requirements as of December 31, 2019 per the contractual maturities, excluding extension options and excluding operating and finance leases, are as follows (in thousands): ​ ​ ​ ​ ​ 2020 $ 64 2021 ​ ​ 73 2022 ​ ​ 1,599 2023 ​ ​ 317,028 2024 ​ ​ 225,000 Thereafter ​ ​ 875,000 Total ​ $ 1,418,764 ​ As of December 31, 2019, we were in compliance with all of our covenants.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Income Taxes	9. Income Taxes ​ The Company has elected for two of its existing subsidiaries to be taxed as taxable REIT subsidiaries pursuant to the REIT rules of the U.S. Internal Revenue Code. Pursuant to the transaction described in Note 3 – Acquisitions, we also have subsidiaries subject to tax in non-US jurisdictions. ​ For the taxable REIT subsidiaries, income taxes are accounted for under the asset and liability method in accordance with ASC Topic 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, ​ 2019 2018 2017 Current: ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. federal ​ $ — ​ $ (50) ​ $ 42 U.S. State ​ ​ 298 ​ ​ 395 ​ ​ 297 Outside United States ​ ​ 13 ​ ​ 78 ​ ​ 44 Total Current ​ ​ 311 ​ ​ 423 ​ ​ 383 Deferred: ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. federal ​ ​ (276) ​ ​ (3,727) ​ ​ (9,734) U.S. State ​ ​ (71) ​ ​ (64) ​ ​ (427) Outside United States ​ ​ (1) ​ ​ — ​ ​ — Total Deferred ​ ​ (348) ​ ​ (3,791) ​ ​ (10,161) Total ​ $ (37) ​ $ (3,368) ​ $ (9,778) ​ Temporary differences and carry forwards which give rise to the deferred tax assets and liabilities are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the Year Ended December 31, ​ 2019 2018 2017 Deferred tax assets ​ ​ ​ ​ ​ ​ ​ ​ ​ Net operating loss carryforwards ​ $ 20,218 ​ $ 17,610 ​ $ 8,888 Deferred revenue and setup charges ​ ​ 1,299 ​ ​ 3,171 ​ ​ 3,435 Operating lease liabilities ​ ​ 2,266 ​ ​ — ​ ​ — Property and equipment ​ ​ 512 ​ ​ — ​ ​ — Leases ​ ​ — ​ ​ 1 ​ ​ 453 Credits ​ ​ 300 ​ ​ 287 ​ ​ 543 Bad debt reserve ​ ​ 18 ​ ​ 409 ​ ​ 2,250 Intangibles ​ ​ 804 ​ ​ — ​ ​ — Interest expense carryforward IRC Sec. 163(j) ​ ​ 2,782 ​ ​ 2,253 ​ ​ — Other ​ ​ 1,376 ​ ​ 1,534 ​ ​ 1,607 Gross deferred tax assets ​ ​ 29,575 ​ ​ 25,265 ​ ​ 17,176 Deferred tax liabilities ​ ​ ​ ​ ​ ​ ​ ​ ​ Property and equipment ​ ​ — ​ ​ (3,089) ​ ​ (4,940) Goodwill ​ ​ (2,494) ​ ​ (1,953) ​ ​ (1,396) Intangibles ​ ​ (591) ​ ​ (11,910) ​ ​ (13,606) Operating lease right-of-use assets ​ ​ (1,261) ​ ​ — ​ ​ — Other ​ ​ (1,231) ​ ​ (1,049) ​ ​ (1,132) Gross deferred tax liabilities ​ ​ (5,577) ​ ​ (18,001) ​ ​ (21,074) Net deferred tax asset/(liability) ​ ​ 23,998 ​ ​ 7,264 ​ ​ (3,898) Valuation allowance ​ ​ (24,747) ​ ​ (8,361) ​ ​ (713) Net deferred tax liability ​ $ (749) ​ $ (1,097) ​ $ (4,611) ​ The taxable REIT subsidiaries currently have net operating loss carryforwards related to federal income taxes of $33.4 million that expire in 10-17 years and $39.9 million which have no expiration. The taxable REIT subsidiaries also have $78.4 million of net operating loss carryforwards relating to state income taxes that expire in 1-20 years. The Company’s interest expense carryforward of $10.9 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, ​ 2019 2018 2017 TRS ​ ​ ​ ​ ​ ​ ​ ​ ​ Statutory rate applied to pre-tax loss ​ $ (12,991) ​ $ (9,656) ​ $ (5,109) Permanent differences, net ​ ​ 16 ​ ​ 97 ​ ​ (284) State income tax, net of federal benefit ​ ​ (2,868) ​ ​ (1,430) ​ ​ (388) Foreign income tax ​ ​ 13 ​ ​ 78 ​ ​ 44 Federal and State rate change ​ ​ (20) ​ ​ (146) ​ ​ (3,251) Contribution of Assets to TRS ​ ​ — ​ ​ — ​ ​ (866) Other ​ ​ (110) ​ ​ 41 ​ ​ (244) Valuation allowance increase (decrease) ​ ​ 15,923 ​ ​ 7,648 ​ ​ 320 Total tax benefit ​ $ (37) ​ $ (3,368) ​ $ (9,778) Effective tax rate ​ ​ 0.1% ​ ​ 7.3% ​ ​ 65.1% ​ On December 22, 2017, the Tax Cuts and Jobs Act ("The Act"), was signed into law by President Trump. The tax legislation contains several provisions, including the lowering of the U.S. corporate tax rate from 35 percent to 21 percent, effective January 1, 2018. ​ The Company had significant deferred tax liabilities, primarily related to fixed assets and intangibles, on its balance sheets as of December 31, 2017. The value of the net deferred tax liabilities decreased significantly as a result of the reduction in the U.S. corporate income tax rate. Consequently, operating results for the reporting period ended December 31, 2017 reflected a one-time non-cash income tax benefit of $3.3 million for the re-measurement of deferred tax assets (liabilities). ​ The Act also repealed corporate alternative minimum tax (“AMT”) for tax years beginning January 1, 2018, and provides that existing AMT credit carryforwards are refundable beginning in 2018. The Company has approximately $0.3 million of AMT credit carryovers that are expected to be fully refunded by 2022. The repeal of AMT did not result in any one-time income tax expense (benefit) to operating results. ​ The Company followed the guidance in SEC Staff Accounting Bulletin 118 (“SAB 118”), which provided additional clarification regarding the application of ASC Topic 740 in situations where the Company may not have had the necessary information available, prepared, or analyzed in reasonable detail to complete the accounting for certain income tax effects of the Act for the reporting period ended December 31, 2017 in which the Act was enacted. SAB 118 provided for a measurement period beginning in the reporting period that includes the Act’s enactment date and ending when the Company has obtained, prepared, and analyzed the information needed in order to complete the accounting requirements. In no circumstances was the measurement period to extend beyond one year from the enactment date. ​ The Company completed its accounting for income tax effects of the Act in the reporting period ended December 31, 2018 and included the impacts in its income tax provision from continuing operations in accordance with the measurement period guidance provided in SAB 118. The impacts of completing its accounting were not material to the income tax provision of the Company’s effective tax rate. ​ As of December 31, 2019, 2018 and 2017, the Company had no uncertain tax positions. If the Company accrues 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, 2019, 2018, and 2017, the Company had accrued no such interest or penalties. ​ The Company is currently not under examination by the Internal Revenue Service or any state or foreign jurisdictions. Tax years ending after December 31, 2015 remain subject to examination and assessment, state limitation periods included. Tax years ending December 31, 2009 through December 31, 2015 remain open solely for purposes of examination of our loss and credit carryforwards. ​ The Company provides 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, 2019, 2018, and 2017 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 judgements based on the accumulation of available evidence. Those judgements 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, 2019, 2018, and 2017 valuation allowances of $24.7 million, $8.4 million and $0.7 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 $16.3 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 scheduled reversal of taxable temporary differences; and some portion of the change to the state valuation allowance is attributable to state net operating losses generated where the Company has discontinued its operations or reduced its presence in certain state jurisdictions.

Derivative Instruments

Derivative Instruments	12 Months Ended
	Dec. 31, 2019
Derivative Instruments
Derivative Instruments	10. 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. ​ On April 5, 2017, we entered into forward interest rate swap agreements with an aggregate notional amount of $400 million. The forward swap agreements effectively fix the interest rate on $400 million of term loan borrowings, $200 million of swaps allocated to Term Loan A and $200 million allocated to Term Loan B, from January 2, 2018 through December 17, 2021 and April 27, 2022, respectively. ​ On December 20, 2018, we entered into additional forward interest rate swap agreements with an aggregate notional amount of $400 million. The forward swap agreements effectively fix the interest rate on $400 million of term loan borrowings, $200 million of swaps allocated to Term Loan A and $200 million allocated to Term Loan B, from December 17, 2021 through December 17, 2023 and April 27, 2022 through April 27, 2024, respectively. On December 20, 2018, we entered into additional forward interest rate swap agreements with an aggregate notional amount of $200 million. The forward swap agreements effectively fix the interest rate on $100 million of additional term loan borrowings from January 2, 2020 through December 17, 2023 as well as $100 million of additional term loan borrowings from January 2, 2020 through April 27, 2024. ​ 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, 2019, the fair value of interest rates swaps represented an aggregate $19.9 million liability. As of December 31, 2018, the fair value of interest rate swaps included an asset of $5.3 million as well was a liability of $3.0 million. ​ 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. The amount reclassified from other comprehensive income to interest expense on the consolidated statements of operations was a reduction to interest expense of $1.0 million and an increase to interest expense of ​ Interest rate derivatives and their fair values as of December 31, 2019 and December 31, 2018 were as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fixed One Month ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Notional Amount ​ LIBOR rate per ​ ​ ​ ​ ​ Fair Value (1) December 31, 2019 December 31, 2018 annum Effective Date Expiration Date December 31, 2019 December 31, 2018 $ 25,000 ​ $ 25,000 ​ 1.989% ​ January 2, 2018 ​ December 17, 2021 ​ $ (209) ​ $ 331 ​ 100,000 ​ ​ 100,000 ​ 1.989% ​ January 2, 2018 ​ December 17, 2021 ​ ​ (837) ​ ​ 1,318 ​ 75,000 ​ ​ 75,000 ​ 1.989% ​ January 2, 2018 ​ December 17, 2021 ​ ​ (627) ​ ​ 990 ​ 50,000 ​ ​ 50,000 ​ 2.033% ​ January 2, 2018 ​ April 27, 2022 ​ ​ (545) ​ ​ 667 ​ 100,000 ​ ​ 100,000 ​ 2.029% ​ January 2, 2018 ​ April 27, 2022 ​ ​ (1,081) ​ ​ 1,341 ​ 50,000 ​ ​ 50,000 ​ 2.033% ​ January 2, 2018 ​ April 27, 2022 ​ ​ (545) ​ ​ 666 ​ 100,000 ​ ​ 100,000 ​ 2.617% ​ January 2, 2020 ​ December 17, 2023 ​ ​ (4,007) ​ ​ (782) ​ 100,000 ​ ​ 100,000 ​ 2.621% ​ January 2, 2020 ​ April 27, 2024 ​ ​ (4,324) ​ ​ (818) ​ 200,000 ​ ​ 200,000 ​ 2.636% ​ December 17, 2021 ​ December 17, 2023 ​ ​ (3,939) ​ ​ (722) ​ 200,000 ​ ​ 200,000 ​ 2.642% ​ April 27, 2022 ​ April 27, 2024 ​ ​ (3,802) ​ ​ (648) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ $ (19,916) ​ $ 2,343 ​ 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 datacenters 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 $0.7 million for the year ended December 31, 2019. There was no amount reclassified from other comprehensive income to utilities expense for the years ended December 31, 2018 or 2017. 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, 2019 and December 31, 2018 were as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair Value Counterparty ​ Facility ​ Effective Date ​ Expiration Date ​ December 31, 2019 December 31, 2018 Calpine Energy Solutions, LLC ​ Piscataway ​ 3/8/2019 ​ 2/28/2029 ​ $ (2,919) ​ $ — Calpine Energy Solutions, LLC ​ Chicago ​ 3/8/2019 ​ 2/28/2029 ​ ​ (3,774) ​ ​ — ​ ​ ​ ​ ​ ​ ​ ​ $ (6,693) ​ $ — ​

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2019
Commitments and Contingencies [Abstract]
Commitments and Contingencies	11. Commitments and Contingencies ​ The Company is subject to various routine legal proceedings and other matters in the ordinary course of business. The Company currently does not have any litigation that would have a material adverse impact on the Company’s financial statements.

Partners' Capital, Equity and I

Partners' Capital, Equity and Incentive Compensation Plans	12 Months Ended
	Dec. 31, 2019
Partners' Capital, Equity and Incentive Compensation Plans [Abstract]
Partners' Capital, Equity and Incentive Compensation Plans	12. Partners’ Capital, Equity and Incentive Compensation Plans ​ QualityTech, 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, 2019, 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 3,000,000. 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 1,110,000 to 5,860,000. ​ 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 ending December 31, 2020 (performance-based FFO units or “FFO Units”), with two -thirds of the earned shares of Class A common stock vesting at the end of the performance period when results have been certified and the remaining one -third of the shares vesting 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 ending December 31, 2021 (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, 2019, 2018 and 2017: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2010 Equity Incentive Plan ​ 2013 Equity Incentive Plan ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ Restricted ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ Weighted ​ ​ ​ Weighted ​ average ​ Stock / ​ Weighted ​ ​ ​ Weighted ​ ​ ​ Weighted ​ ​ ​ Number of ​ average ​ Average fair ​ ​ ​ average ​ fair ​ Deferred ​ average ​ ​ ​ average ​ ​ ​ average ​ ​ Class O units exercise price value Options exercise price value Stock grant price TSR Units grant price FFO Units grant price ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Outstanding at January 1, 2017 ​ ​ 1,134,811 ​ $ 24.06 ​ $ 3.62 ​ 1,058,297 ​ $ 31.72 ​ $ 6.51 ​ 414,691 ​ $ 40.67 ​ — ​ $ — ​ — ​ $ — Granted ​ ​ — ​ ​ — ​ ​ — ​ 468,875 ​ ​ 50.66 ​ ​ 10.32 ​ 228,576 ​ ​ 49.86 ​ — ​ ​ — ​ — ​ ​ — Exercised/Vested (1) ​ ​ (566,771) ​ ​ 24.60 ​ ​ 2.24 ​ (155,902) ​ ​ 31.89 ​ ​ 6.60 ​ (163,048) ​ ​ 40.63 ​ — ​ ​ — ​ — ​ ​ — Cancelled/Expired (2) ​ ​ — ​ ​ — ​ ​ — ​ (2,000) ​ ​ 37.69 ​ ​ 8.77 ​ (98,355) ​ ​ 39.97 ​ — ​ ​ — ​ — ​ ​ — Outstanding at December 31, 2017 ​ ​ 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 (2) ​ ​ — ​ ​ — ​ ​ — ​ — ​ ​ — ​ ​ — ​ (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 ​ ​ ​ ​ ​ 42.01 Exercised/Vested (1) ​ ​ (19,969) ​ ​ 20.25 ​ ​ 4.42 ​ (125,213) ​ ​ 30.80 ​ ​ 6.21 ​ (279,429) ​ ​ 39.20 ​ — ​ ​ — ​ — ​ ​ — Cancelled/Expired (2) ​ ​ — ​ ​ — ​ ​ — ​ (112,706) ​ ​ 45.86 ​ ​ 9.43 ​ (25,694) ​ ​ 42.17 ​ (1,739) ​ ​ ​ (1,739) ​ ​ 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 (1) This 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) Includes restricted Class A common stock surrendered by certain employees to satisfy their statutory minimum federal and state tax obligations associated with the vesting of restricted common stock. ​ 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, 2019, 2018 and 2017 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. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2019 2018 2017 Fair value of FFO units and restricted stock granted ​ ​ $42.01 - $51.25 ​ ​ $34.03 - $54.01 ​ ​ $48.63 - $51.88 Fair value of TSR units granted ​ ​ $54.64 ​ ​ N/A ​ ​ N/A Fair value of options granted ​ ​ $7.56 - $8.28 ​ ​ $5.55 - $5.64 ​ ​ $10.11 - $10.36 Expected term (years) ​ ​ 5.5 ​ ​ 5.5 - 6.0 ​ ​ 5.5 - 5.9 Expected volatility ​ ​ 28% ​ ​ 28% ​ ​ 28% Expected dividend yield ​ ​ 3.89% - 4.19% ​ ​ 4.82% ​ ​ 3.08% Expected risk-free interest rates ​ ​ 2.33% - 2.56% ​ ​ 2.69% - 2.73% ​ ​ 2.12% - 2.18% ​ The following tables summarize information about awards outstanding as of December 31, 2019. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Operating Partnership Awards Outstanding ​ ​ ​ ​ ​ ​ ​ Weighted average ​ ​ ​ ​ ​ Awards ​ remaining ​ Exercise prices outstanding vesting period (years) Class O Units ​ $ 20.00 - 25.00 ​ 82,310 ​ — Total Operating Partnership awards outstanding ​ ​ ​ ​ 82,310 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ QTS Realty Trust, Inc. Awards Outstanding ​ ​ ​ ​ ​ ​ ​ Weighted average ​ ​ ​ ​ ​ Awards ​ remaining ​ Exercise prices outstanding vesting period (years) Restricted stock ​ $ — ​ 389,750 ​ 1.7 TSR units ​ ​ — ​ 84,350 ​ 2.0 FFO units ​ ​ — ​ 84,350 ​ 1.4 Options to purchase Class A common stock ​ $ 21.00 - 50.66 ​ 1,934,838 ​ 0.3 Total QTS Realty Trust, Inc. awards outstanding ​ ​ ​ ​ 2,493,288 ​ ​ ​ Any remaining nonvested awards are valued as of the grant date and generally vest ratably over a defined service period. As of December 31, 2019 all restricted Class A common stock, TSR units, and FFO units outstanding were unvested and approximately 0.6 million options to purchase Class A common stock were outstanding and unvested. As of December 31, 2019 we had $17.0 million of unrecognized equity-based compensation expense which will be recognized over a remaining weighted-average vesting period of 1.1 years. The total intrinsic value of Class O units and options to purchase Class A common stock outstanding at December 31, 2019 was $35.4 million. ​ Dividends and Distributions ​ The following tables present quarterly cash dividends and distributions paid to QTS’ common and preferred stockholders and the Operating Partnership’s unit holders for the years ended December 31, 2019 and 2018: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31, 2019 ​ ​ ​ ​ ​ ​ ​ Aggregate ​ ​ ​ ​ Per Share and ​ Dividend/Distribution Record Date Payment Date Per Unit Rate Amount (in millions) Common Stock/Units ​ ​ ​ ​ ​ ​ ​ ​ 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/Units ​ ​ ​ ​ ​ ​ ​ ​ 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/Units ​ ​ ​ ​ ​ ​ ​ ​ 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 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31, 2018 ​ ​ ​ ​ ​ ​ ​ Aggregate ​ ​ ​ ​ Per Share and ​ Dividend/Distribution Record Date Payment Date Per Unit Rate Amount (in millions) Common Stock/Units ​ ​ ​ ​ ​ ​ ​ ​ September 20, 2018 ​ October 4, 2018 ​ $ 0.41 ​ $ 23.7 June 20, 2018 ​ July 6, 2018 ​ ​ 0.41 ​ ​ 23.7 March 22, 2018 ​ April 5, 2018 ​ ​ 0.41 ​ ​ 23.7 December 5, 2017 ​ January 5, 2018 ​ ​ 0.39 ​ ​ 22.2 ​ ​ ​ ​ ​ ​ ​ $ 93.3 ​ ​ ​ ​ ​ ​ ​ ​ ​ Series A Preferred Stock/Units ​ ​ ​ ​ ​ ​ ​ ​ September 28, 2018 ​ October 15, 2018 ​ $ 0.45 ​ $ 1.9 June 29, 2018 ​ July 16, 2018 ​ ​ 0.45 ​ ​ 1.9 April 5, 2018 ​ April 16, 2018 ​ ​ 0.15 ​ ​ 0.6 ​ ​ ​ ​ ​ ​ ​ $ 4.4 ​ ​ ​ ​ ​ ​ ​ ​ ​ Series B Preferred Stock/Units ​ ​ ​ ​ ​ ​ ​ ​ September 30, 2018 ​ October 15, 2018 ​ $ 1.99 ​ $ 6.3 ​ ​ ​ ​ ​ ​ ​ $ 6.3 ​ Additionally, subsequent to December 31, 2019, the Company paid the following dividends: ​ ● On January 7, 2020 , the Company paid its regular quarterly cash dividend of $0.44 per common share and per unit in the Operating Partnership to stockholders and unit holders of record as of the close of business on December 20, 2019 . ​ ● On January 15, 2020 , the Company paid a quarterly cash dividend of approximately $0.45 per share on its Series A Preferred Stock to holders of Series A Preferred Stock of record as of the close of business on December 31, 2019 , and the Operating Partnership paid a quarterly cash distribution of approximately $0.45 per unit on outstanding Series A Preferred Units held by the Company. ​ ● On January 15, 2020 , the Company paid a quarterly cash dividend of approximately $1.63 per share on its Series B Preferred Stock to holders of Series B Preferred Stock of record as of the close of business on December 31, 2019 , and the Operating Partnership paid a quarterly cash distribution of approximately $1.63 per unit on outstanding Series B Preferred Units held by the Company. ​ Equity Issuances ​ Class A Common Stock ​ In February 2019, QTS conducted an underwritten offering of 7,762,500 shares of its Class A common stock, $0.01 par value per share (the “Class A common stock”) consisting of 4,000,000 shares issued by the Company during the first quarter of 2019 and 3,762,500 shares which will be issued on a forward basis. During the year ended December 31, 2019, we settled a portion of the shares subject to the forward sale agreements. See the table below for additional quantitative information related to the stock offerings. 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 by other fixed amounts specified in the forward sale agreement. Until settlement of all of the forward sale agreements, our earnings per share dilution resulting from the agreements, if any, is determined using the two-class method. ​ In June 2019, we established a new “at-the-market” equity offering program (the “ATM Program”) pursuant to which we may issue, from time to time, up to $400 million of our Class A common stock, which may include shares to be sold on a forward basis. The use of forward sales under the ATM Program generally allows the Company 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 by other fixed amounts specified in the forward sale agreement. Until settlement of all of the forward sale agreements, our earnings per share dilution resulting from the agreements, if any, is determined using the two-class method. ​ At any time during the term of any forward sale under the 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. The Company expects to physically settle (by delivering shares of Class A common stock) these forward sales prior to the first anniversary date of each respective transaction. ​ The following table represents a summary of our equity issuances of our Class A common stock during the year ended December 31, 2019 (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Offering Program Forward Shares Settled ​ Net ​ Remaining Expected Forward Settlement (1) February 2019 Offering ​ N/A ​ 4,000 ​ ​ $ 159,360 ​ $ - ​ N/A February 2019 Offering ​ 3,763 ​ 2,832 (2) ​ ​ 109,998 ​ ​ 35,799 ​ March 31, 2020 June 2019 $400 million ATM Program ​ 2,864 ​ - ​ ​ ​ - ​ ​ 142,046 ​ Various through January 17, 2021 Total as of December 31, 2019 ​ ​ ​ ​ ​ ​ ​ ​ ​ $ 177,844 ​ ​ (1) Represents the final date which shares sold under each forward agreement may be settled. (2) Represents the number of forward shares we elected to physically settle during the year ended December 31, 2019. ​ 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. The Company used the net proceeds of approximately $103.2 million to repay amounts outstanding under its unsecured revolving credit facility. 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 first dividend on the Series A Preferred Stock was paid on April 16, 2018, in the amount of $0.14844 per share for the period March 15, 2018 through April 14, 2018. 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’s 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. The Company used the net proceeds of approximately $304 million to repay amounts outstanding under its unsecured revolving credit facility. 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 first dividend on the Series B Preferred Stock was paid on October 15, 2018, in the amount of $1.9861111 per share for the period June 25, 2018 through October 14, 2018. 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, 2019 is 2.1318 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-year holding period following the purchase date, during which they may not be sold or transferred. We reserved 239,989 shares of our Class A common stock, subject to certain adjustments, for purchase under the 2017 Plan, which were registered pursuant to a registration statement on Form S-8 originally filed on June 17, 2015 and amended on June 30, 2017. ​ 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, 2019
Related Party Transactions [Abstract]
Related Party Transactions	13. Related Party Transactions ​ As described further in Note 7 Investments in Unconsolidated Entity ​ 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. During the year ended December 31, 2019, QTS received $0.6 million in development fees from the unconsolidated entity as well as $0.6 million in management fees from the unconsolidated entity. ​ 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, 2019, 2018 and 2017 are outlined below (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, (dollars in thousands) 2019 2018 2017 Tax, utility, insurance and other reimbursement ​ $ 967 ​ $ 724 ​ $ 796 Rent expense ​ ​ 1,014 ​ ​ 1,014 ​ ​ 1,014 Capital assets acquired ​ ​ 704 ​ ​ 464 ​ ​ 561 Total ​ $ 2,685 ​ $ 2,202 ​ $ 2,371 ​

Employee Benefit Plan

Employee Benefit Plan	12 Months Ended
	Dec. 31, 2019
Employee Benefit Plan [Abstract]
Employee Benefit Plan	14. Employee Benefit Plan ​ The Company sponsors 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, the Company has matched 100% of the first 1% of contributions and 50% of the next 5% of contributions made by employees. The Company contributed $2.5 million, $2.5 million and $2.6 million to the 401(k) Plan for the years ended December 31, 2019, 2018 and 2017, respectively.

Noncontrolling Interest

Noncontrolling Interest	12 Months Ended
	Dec. 31, 2019
Noncontrolling Interest [Abstract]
Noncontrolling Interest	15. Noncontrolling Interest ​ Concurrently with the completion of the IPO, QTS 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, 2019, the noncontrolling ownership interest percentage of QualityTech, LP was 10.3%. ​

Earnings per share of QTS Realt

Earnings per share of QTS Realty Trust, Inc.	12 Months Ended
	Dec. 31, 2019
Earnings per Share [Abstract]
Earnings per Share	16. Earnings per share of QTS Realty Trust, Inc. ​ Basic income per share is calculated by dividing the net income attributable to common shares by the weighted average number of common shares outstanding during the period. Diluted income 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 per share is as follows (in thousands, except per share data): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended ​ ​ December 31, ​ 2019 2018 2017 Numerator: ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income (loss) ​ $ 31,665 ​ $ (7,175) ​ $ 1,457 Loss (income) attributable to noncontrolling interests ​ ​ (374) ​ ​ 2,715 ​ ​ (175) Preferred stock dividends ​ ​ (28,180) ​ ​ (16,666) ​ ​ — Earnings attributable to participating securities ​ ​ (7,828) ​ ​ (947) ​ ​ (593) Net income (loss) available to common stockholders after allocation of participating securities ​ $ (4,717) ​ $ (22,073) ​ $ 689 Denominator: ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted average shares outstanding - basic ​ ​ 54,837 ​ ​ 50,433 ​ ​ 48,381 Effect of Class A partnership units ​ ​ — ​ ​ — ​ ​ 6,696 Effect of Class O units, TSR units and options to purchase Class A common stock on an "as if" converted basis ​ ​ — ​ ​ — ​ ​ 779 Weighted average shares outstanding - diluted ​ ​ 54,837 ​ ​ 50,433 ​ ​ 55,856 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Basic net income (loss) per share ​ $ (0.09) ​ $ (0.44) ​ $ 0.01 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Diluted net income (loss) per share ​ $ (0.09) ​ $ (0.44) ​ $ 0.01 * 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 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, ​ 2019 2018 2017 Class A Partnership units ​ ​ 6,671 ​ ​ 6,653 ​ ​ — Class O units, TSR units and options to purchase common stock on an "as if" converted basis ​ ​ 518 ​ ​ 350 ​ ​ — Series B Convertible preferred stock on an "as if" converted basis ​ ​ 6,729 ​ ​ 3,484 ​ ​ — ​

Contracts with Customers

Contracts with Customers	12 Months Ended
	Dec. 31, 2019
Contracts with Customers [Abstract]
Contracts with Customers	17. 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 the practical expedient provided by 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 Ending December 31, ​ ​ 2020 $ 374,588 2021 ​ ​ 323,926 2022 ​ ​ 237,556 2023 ​ ​ 147,941 2024 ​ ​ 103,663 Thereafter ​ ​ 186,871 Total ​ $ 1,374,545 ​

Fair Value of Financial Instrum

Fair Value of Financial Instruments	12 Months Ended
	Dec. 31, 2019
Fair Value of Financial Instruments [Abstract]
Fair Value of Financial Instruments	18. 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: ​ 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, 2019, 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, 2019 or December 31, 2018. ​ 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: 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. ​ Credit facility and Senior Notes: ​ 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, 2019
Quarterly Financial Information [Abstract]
Quarterly Financial Information	19. Quarterly Financial Information (unaudited) ​ The tables below reflect the selected quarterly information for the years ended December 31, 2019 and 2018 for QTS (in thousands except share data): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ December 31, September 30, June 30, March 31, 2019 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Revenues ​ $ 123,707 ​ $ 125,255 ​ $ 119,167 ​ $ 112,689 Operating income (loss) ​ ​ 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 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2018 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Revenues ​ $ 112,337 ​ $ 112,213 ​ $ 112,277 ​ $ 113,697 Operating income (loss) ​ ​ 12,876 ​ ​ (1,552) ​ ​ 1,882 ​ ​ 5,455 Net income (loss) ​ ​ 6,402 ​ ​ (6,892) ​ ​ (6,433) ​ ​ (252) Net income (loss) attributable to QTS Realty Trust, Inc. ​ ​ 6,476 ​ ​ (5,282) ​ ​ (5,431) ​ ​ (223) Net income (loss) attributable to common stockholders ​ ​ (569) ​ ​ (12,327) ​ ​ (7,679) ​ ​ (551) Net income (loss) per share attributable to common shares - basic ​ ​ (0.02) ​ ​ (0.25) ​ ​ (0.16) ​ ​ (0.02) Net income (loss) per share attributable to common shares - diluted ​ ​ (0.02) ​ ​ (0.25) ​ ​ (0.16) ​ ​ (0.02) ​ The table below reflects the selected quarterly information for the years ended December 31, 2019 and 2018 for the Operating Partnership (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ December 31, September 30, June 30, March 31, 2019 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Revenues ​ $ 123,707 ​ $ 125,255 ​ $ 119,167 ​ $ 112,689 Operating income (loss) ​ ​ 4,218 ​ ​ 13,606 ​ ​ 14,598 ​ ​ 28,734 Net income (loss) ​ ​ (3,606) ​ ​ 6,588 ​ ​ 7,535 ​ ​ 21,148 Net income (loss) attributable to common unitholders ​ ​ (10,651) ​ ​ (457) ​ ​ 490 ​ ​ 14,103 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2018 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Revenues ​ $ 112,337 ​ $ 112,213 ​ $ 112,277 ​ $ 113,697 Operating income (loss) ​ ​ 12,876 ​ ​ (1,552) ​ ​ 1,882 ​ ​ 5,455 Net income (loss) ​ ​ 6,402 ​ ​ (6,892) ​ ​ (6,433) ​ ​ (252) Net income (loss) attributable to common unitholders ​ ​ (643) ​ ​ (13,937) ​ ​ (8,681) ​ ​ (580) ​

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2019
Subsequent Events [Abstract]
Subsequent Events	20. Subsequent Events ​ In January 2020, 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, 2019, the Company authorized the following dividends: ​ ● On February 18, 2020 , the Company announced that its board of directors authorized payment of a regular quarterly cash dividend of $0.47 per common share and per unit in the Operating Partnership, payable on April 7, 2020 , to stockholders and unit holders of record as of the close of business on March 20, 2020 . ​ ● On February 18, 2020 , 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, 2020 , to holders of Series A Preferred Stock of record as of the close of business on March 31, 2020 . ​ ● On February 18, 2020 , the Company announced that its board of directors authorized payment of a regular quarterly cash dividend of approximately $1.63 per share on its Series B Preferred Stock, payable on April 15, 2020 , to holders of Series B Preferred Stock of record as of the close of business on March 31, 2020 . ​ Subsequent to December 31, 2019 through February 28, 2020, we utilized the forward provisions under the ATM Program to allow for the sale of up to an aggregate of 0.8 million shares of our common stock, representing available net proceeds upon physical settlement of approximately $41.6 million. Through February 28, 2020, we had not settled any of these forward sales.

Schedule II - Valuation and Qua

Schedule II - Valuation and Qualifying Accounts	12 Months Ended
	Dec. 31, 2019
Schedule II - Valuation and Qualifying Accounts [Abstract]
Schedule II - Valuation and Qualifying Accounts	QTS REALTY TRUST, INC. QUALITYTECH, LP SCHEDULE II – VALUATION AND QUALIFYING ACCOUNTS December 31, 2019 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Balance at ​ ​ ​ ​ ​ ​ ​ Balance at Year Ended December 31, ​ beginning of ​ Charge to ​ Additions/ ​ end of (dollars in thousands) period expenses (Deductions) period ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Allowance for uncollectible receivables ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2019 ​ $ 3,764 ​ $ 2,859 ​ $ (4,344) ​ $ 2,279 2018 ​ ​ 11,453 ​ ​ (2,275) ​ ​ (5,414) ​ ​ 3,764 2017 ​ ​ 4,217 ​ ​ 7,375 ​ ​ (139) ​ ​ 11,453 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Valuation allowance for deferred tax assets ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2019 ​ $ 8,361 ​ $ 16,386 ​ $ — ​ $ 24,747 2018 ​ ​ 713 ​ ​ 7,648 ​ ​ — ​ ​ 8,361 2017 ​ ​ 393 ​ ​ 320 ​ ​ — ​ ​ 713 ​

Schedule III - Real Estate Inve

Schedule III - Real Estate Investments	12 Months Ended
	Dec. 31, 2019
Schedule III - Real Estate Investments [Abstract]
Schedule III - Real Estate Investments	QTS REALTY TRUST, INC. QUALITYTECH, LP SCHEDULE III – REAL ESTATE INVESTMENTS December 31, 2019 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Initial Costs ​ Costs Capitalized Subsequent to Acquisition ​ Gross Carrying Amount ​ ​ ​ ​ ​ As of December 31, 2019 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Accumulated ​ ​ (dollars in thousands) ​ ​ ​ ​ Buildings and ​ Construction ​ ​ ​ ​ Buildings and ​ Construction ​ ​ ​ ​ Buildings and ​ Construction ​ Depreciation and ​ Date of Property Location Land Improvements in Progress Land Improvements in Progress Land Improvements in Progress Amortization (1) Acquisition Owned Properties ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Atlanta, Georgia Campus (2) ​ $ 12,647 ​ $ 35,473 ​ $ 2,209 ​ $ 31,941 ​ $ 489,827 ​ $ 126,721 ​ $ 44,588 ​ $ 525,300 ​ $ 128,930 ​ $ (190,566) ​ 10/3/2006 Irving, Texas ​ ​ — ​ ​ 5,808 ​ ​ — ​ ​ 8,606 ​ ​ 363,919 ​ ​ 98,170 ​ ​ 8,606 ​ ​ 369,727 ​ ​ 98,170 ​ ​ (59,719) ​ 2/8/2013 Richmond, Virginia ​ ​ 2,000 ​ ​ 11,200 ​ ​ 7,029 ​ ​ 180 ​ ​ 184,484 ​ ​ 132,919 ​ ​ 2,180 ​ ​ 195,684 ​ ​ 139,948 ​ ​ (74,056) ​ 3/20/2010 & 11/15/2019 Chicago, Illinois ​ ​ — ​ ​ — ​ ​ 17,764 ​ ​ 9,400 ​ ​ 205,026 ​ ​ 69,114 ​ ​ 9,400 ​ ​ 205,026 ​ ​ 86,878 ​ ​ (19,760) ​ 7/8/2014 Suwanee, Georgia (Atlanta-Suwanee) ​ ​ 1,395 ​ ​ 29,802 ​ ​ — ​ ​ 2,126 ​ ​ 144,322 ​ ​ 5,559 ​ ​ 3,521 ​ ​ 174,124 ​ ​ 5,559 ​ ​ (78,510) ​ 9/1/2005 Piscataway, New Jersey ​ ​ 7,466 ​ ​ 80,366 ​ ​ 13,900 ​ ​ — ​ ​ 23,187 ​ ​ 22,156 ​ ​ 7,466 ​ ​ 103,553 ​ ​ 36,056 ​ ​ (10,634) ​ 6/6/2016 Santa Clara, California ​ ​ — ​ ​ 15,838 ​ ​ — ​ ​ — ​ ​ 98,661 ​ ​ 1,238 ​ ​ — ​ ​ 114,499 ​ ​ 1,238 ​ ​ (46,536) ​ 11/1/2007 Sacramento, California ​ ​ 1,481 ​ ​ 52,753 ​ ​ — ​ ​ — ​ ​ 12,505 ​ ​ 163 ​ ​ 1,481 ​ ​ 65,258 ​ ​ 163 ​ ​ (13,905) ​ 12/21/2012 Fort Worth, Texas ​ ​ 136 ​ ​ 610 ​ ​ 48,984 ​ ​ 8,943 ​ ​ 54,408 ​ ​ (13,262) ​ ​ 9,079 ​ ​ 55,018 ​ ​ 35,722 ​ ​ (3,240) ​ 12/16/2016 Princeton, New Jersey ​ ​ 20,700 ​ ​ 32,126 ​ ​ — ​ ​ — ​ ​ 3,066 ​ ​ 39 ​ ​ 20,700 ​ ​ 35,192 ​ ​ 39 ​ ​ (5,107) ​ 6/30/2014 Dulles, Virginia ​ ​ 3,154 ​ ​ 29,583 ​ ​ — ​ ​ — ​ ​ 19,068 (3) ​ 4,688 ​ ​ 3,154 ​ ​ 48,651 ​ ​ 4,688 ​ ​ (11,831) (3) 10/6/2017 Ashburn, Virginia (4) ​ ​ — ​ ​ — ​ ​ 75,371 ​ ​ 16,476 ​ ​ 156,396 ​ ​ 114,004 ​ ​ 16,476 ​ ​ 156,396 ​ ​ 189,375 ​ ​ (7,363) ​ 8/9/2017 & 10/23/2017 & 7/22/2019 Eemshaven, Netherlands ​ ​ — ​ ​ — ​ ​ 29,915 ​ ​ — ​ ​ — ​ ​ 7,352 ​ ​ — ​ ​ — ​ ​ 37,267 ​ ​ — ​ 4/23/2019 Phoenix, Arizona (4) ​ ​ — ​ ​ — ​ ​ 24,668 ​ ​ — ​ ​ 2,412 ​ ​ 7,172 ​ ​ — ​ ​ 2,412 ​ ​ 31,840 ​ ​ (1,489) ​ 8/11/2017 Groningen, Netherlands ​ ​ 1,743 ​ ​ 8,640 ​ ​ — ​ ​ (2) ​ ​ 445 ​ ​ 3,028 ​ ​ 1,741 ​ ​ 9,085 ​ ​ 3,028 ​ ​ (451) ​ 4/23/2019 Hillsboro, Oregon (4) ​ ​ — ​ ​ — ​ ​ 25,657 ​ ​ — ​ ​ — ​ ​ 37,916 ​ ​ — ​ ​ — ​ ​ 63,573 ​ ​ — ​ 10/3/2017 Miami, Florida ​ ​ 1,777 ​ ​ 6,955 ​ ​ — ​ ​ — ​ ​ 24,486 ​ ​ 119 ​ ​ 1,777 ​ ​ 31,441 ​ ​ 119 ​ ​ (12,419) ​ 3/6/2008 Lenexa, Kansas ​ ​ 400 ​ ​ 3,100 ​ ​ — ​ ​ 36 ​ ​ 734 ​ ​ — ​ ​ 436 ​ ​ 3,834 ​ ​ — ​ ​ (580) ​ 6/3/2011 Manassas, Virginia ​ ​ — ​ ​ — ​ ​ 24,626 ​ ​ — ​ ​ — ​ ​ 33,036 ​ ​ — ​ ​ — ​ ​ 57,662 ​ ​ (1) ​ ​ ​ ​ $ 52,899 ​ $ 312,254 ​ $ 270,123 ​ $ 77,706 ​ $ 1,782,946 ​ $ 650,132 ​ $ 130,605 ​ $ 2,095,200 ​ $ 920,255 ​ $ (536,167) ​ ​ Leased Properties ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Leased Facilities acquired in 2015 ​ ​ — ​ ​ 59,087 ​ ​ — ​ ​ — ​ ​ (6,684) ​ ​ 109 ​ ​ — ​ ​ 52,403 ​ ​ 109 ​ ​ (7,797) ​ 6/16/2015 Jersey City, New Jersey ​ ​ — ​ ​ 1,985 ​ ​ — ​ ​ — ​ ​ 28,425 ​ ​ 557 ​ ​ — ​ ​ 30,410 ​ ​ 557 ​ ​ (13,938) ​ 11/1/2006 Overland Park, Kansas ​ ​ — ​ ​ — ​ ​ — ​ ​ — ​ ​ 888 ​ ​ 1 ​ ​ — ​ ​ 888 ​ ​ 1 ​ ​ (658) ​ ​ ​ ​ $ — ​ $ 61,072 ​ $ — ​ $ — ​ $ 22,629 ​ $ 667 ​ $ — ​ $ 83,700 ​ $ 667 ​ $ (22,393) ​ ​ ​ ​ $ 52,899 ​ $ 373,326 ​ $ 270,123 ​ $ 77,706 ​ $ 1,805,575 ​ $ 650,799 ​ $ 130,605 ​ $ 2,178,901 ​ $ 920,922 ​ $ (558,560) ​ ​ (1) See Note 2 - ‘Summary of Significant Accounting Policies’ for information regarding asset lives on which depreciation and amortization are calculated. (2) 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 megascale data center Atlanta (DC-2) on land adjacent to the existing Atlanta DC-1 facility. (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. (4) 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. ​ The aggregate gross cost of the Company’s properties for federal income tax purposes was $3.41 billion (unaudited) as of December 31, 2019. The following table reconciles the historical cost and accumulated depreciation for the years ended December 31, 2019, 2018 and 2017 (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31, ​ 2019 2018 2017 Property ​ ​ ​ ​ ​ ​ ​ ​ ​ Balance, beginning of period ​ $ 2,812,856 ​ $ 2,357,322 ​ $ 1,964,857 Disposals ​ ​ (41,363) ​ ​ (43,616) ​ ​ (18,198) Additions (acquisitions and improvements) ​ ​ 458,935 ​ ​ 499,150 ​ ​ 410,663 Balance, end of period ​ $ 3,230,428 ​ $ 2,812,856 ​ $ 2,357,322 Accumulated depreciation ​ ​ ​ ​ ​ ​ ​ ​ ​ Balance, beginning of period ​ $ (467,644) ​ $ (394,823) ​ $ (317,834) Disposals ​ ​ 28,172 ​ ​ 30,139 ​ ​ 13,970 Additions (depreciation and amortization expense) ​ ​ (119,088) ​ ​ (102,960) ​ ​ (90,959) Balance, end of period ​ $ (558,560) ​ $ (467,644) ​ $ (394,823) ​

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2019
Summary of Significant 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. ​ The accompanying financial statements are presented for both QTS Realty Trust, Inc. and QualityTech, LP. 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 ASC Topic 810 Consolidation ​ 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. ​ The Company believes, therefore, that providing one set of notes for the financial statements of QTS and the Operating Partnership provides the following benefits: ​ ● enhances investors’ understanding of QTS and the Operating Partnership by enabling investors to view the business as a whole in the same manner as management views and operates the business; ● eliminates duplicative disclosure and provides a more streamlined and readable presentation since a substantial portion of the disclosure applies to both QTS and the Operating Partnership; and ● creates time and cost efficiencies through the preparation of one set of notes instead of two separate sets of notes. ​ In addition, in light of these combined notes, the Company believes it is important for investors to understand the few differences between QTS and the Operating Partnership in the context of how QTS and the Operating Partnership operate as a consolidated company. With respect to balance sheets, the presentation of stockholders’ equity and partners’ capital are the main areas of difference between the consolidated balance sheets of QTS and those of the Operating Partnership. On the Operating Partnership’s consolidated balance sheets, partners’ capital includes preferred partnership units and common partnership units that are owned by QTS and other partners as well as accumulated other comprehensive income (loss). On QTS’ consolidated balance sheets, stockholders’ equity includes preferred stock, common stock, additional paid in capital, accumulated other comprehensive income (loss) and accumulated dividends in excess of earnings. The remaining equity reflected on QTS’s consolidated balance sheet is the portion of net assets that are retained by partners other than QTS, referred to as noncontrolling interests. With respect to statements of operations, the primary difference in QTS' Statements of Operations and Statements of Comprehensive Income (Loss) is that for net income (loss), QTS retains its proportionate share of the net income (loss) based on its ownership of the Operating Partnership, with the remaining balance being retained by the Operating Partnership. These combined notes refer to actions or holdings as being actions or holdings of “the Company.” Although the Operating Partnership is generally the entity that enters into contracts, holds assets and issues debt, management believes that these general references to “the Company” in this context is appropriate because the business is one enterprise operated through the Operating Partnership. ​ As discussed above, QTS owns no operating assets and has no operations independent of the Operating Partnership and its subsidiaries. Also, the Operating Partnership owns no operating assets and has no operations independent of its subsidiaries. Obligations under the 4.750% Senior Notes due 2025 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 4.750% Senior Notes due 2025) or any subsidiary guarantor. The indenture governing the 4.750% Senior Notes due 2025 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 investment accounting. This includes the operating results of the Operating Partnership for all periods presented. ​
Use of Estimates	Use of Estimates
Principles of Consolidation	Principles of Consolidation the accounts of QualityTech, LP and its 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 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, 2019, 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 aggregate investment, which was approximately $30.2 million as of December 31, 2019.
Reclassifications	Reclassifications ​
Real Estate Assets	Real Estate Assets
Acquisitions and Sales	Acquisitions and Sales Business Combinations ​ 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. ​ Other acquired intangible assets, which includes platform, above or below market leases, and trade name intangibles, are amortized on a straight-line basis over their respective expected lives. Above or below market leases are amortized 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. The expense associated with trade name intangibles is accounted for as real estate amortization expense, whereas the expense associated with the amortization of platform intangibles is accounted for as non-real estate amortization expense. ​ We account for the sale of assets to non-customers under Financial Accounting Standards Board (“FASB”) Accounting Standards Update (“ASU”) No. 2017-05, Other Income—Gains and Losses from the Derecognition of Nonfinancial Assets 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 ​ 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, 2019, 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, 2019. ​
Assets Held for Sale	Assets Held for Sale ​
Cash and Cash Equivalents	Cash and Cash Equivalents
Deferred Costs	Deferred Costs – Deferred costs, net, on our balance sheets include both financing costs and 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 $3.9 million, $3.9 million and $3.6 million for the years ended December 31, 2019, 2018 and 2017, respectively. 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 year additional term loan, increased capacity of the revolving facility, extended maturity dates as well as decreased the interest rates. During the year ended December 31, 2018, we wrote off unamortized financing costs of $0.6 million in connection with the modification of our unsecured credit facility in November 2018 whereby we decreased the interest rates, modified and/or eliminated certain covenants and extended the term for an additional year. During the year ended December 31, 2017, we wrote off unamortized financing costs of $5.2 million primarily in connection with the replacement of our $300 million 5.875% senior notes with the $400 million of 4.750% notes. ​ Deferred financing costs presented as assets on the balance sheets related to revolving debt arrangements, net of accumulated amortization are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ ​ December 31, (dollars in thousands) 2019 2018 ​ ​ ​ ​ ​ ​ ​ Deferred financing costs ​ $ 13,776 ​ $ 11,530 Accumulated amortization ​ ​ (5,743) ​ ​ (3,859) Deferred financing costs, net ​ $ 8,033 ​ $ 7,671 ​ 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: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ ​ December 31, (dollars in thousands) 2019 2018 ​ ​ ​ ​ ​ ​ ​ Deferred financing costs ​ $ 15,777 ​ $ 14,501 Accumulated amortization ​ ​ (4,937) ​ ​ (2,944) Deferred financing costs, net ​ $ 10,840 ​ $ 11,557 ​ 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 Revenue from Contracts with Customers leasing costs totaled $24.2 million, $21.3 million and $18.5 million for the years ended December 31, 2019, 2018 and 2017, respectively. Deferred leasing costs, net of accumulated amortization are as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ December 31, (dollars in thousands) 2019 2018 ​ ​ ​ ​ ​ ​ ​ Deferred leasing costs ​ $ 77,178 ​ $ 63,018 Accumulated amortization ​ ​ (32,848) ​ ​ (25,593) Deferred leasing costs, net ​ $ 44,330 ​ $ 37,425
Revenue Recognition	Revenue Recognition – Leases Revenue from Contracts with Customers ​ 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 $38.7 million and $29.7 million as of December 31, 2019 and December 31, 2018, respectively. ​ Rental revenue also includes amortization of set-up fees which are amortized over the term of the respective lease as discussed below. ​ 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 of the statements of operations. ​ Other Revenue ​ Other revenue primarily consists of revenue from our cloud and managed service offerings as well as revenue earned from partner channel, management and development fees. We, through our TRS, may provide both our cloud product and use of our managed services to our customers on an individual or combined basis. In both our cloud and managed services offerings 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 cloud and 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 affiliate properties as well as third parties. Management fee revenue is earned based on a contractual percentage of unconsolidated affiliate 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
Advance Rents and Security Deposits	Advance Rents and Security Deposits –
Deferred Income	Deferred Income – deferred income liability which amortizes into rental revenue over the term of the related lease on a straight-line basis. Deferred income was $39.2 million, $33.2 million and $25.3 million as of December 31, 2019, 2018 and 2017, respectively. Additionally, $15.2 million, $12.5 million and $10.7 million of deferred income was amortized into revenue for the years ended December 31, 2019, 2018 and 2017, respectively.
Foreign Currency	Foreign Currency - ​
Equity-based Compensation	Equity-based Compensation
Segment Information	Segment Information
Customer Concentrations	Customer Concentrations ​ As of December 31, 2019, five of our customers exceeded 5% of trade accounts receivable. In aggregate, these five customers accounted for 30% of trade accounts receivable. None of these customers individually exceeded 10% of total 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, as 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 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 federal income and excise tax liability.
Fair Value Measurements	Fair Value Measurements Fair Value Measurement ​ 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, 2019, 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	​ Recently Adopted Accounting Standards ​ Revenue from Contracts with Customers ​ In May 2014, the FASB issued guidance codified in ASC Topic 606, Revenue from Contracts with Customers Revenue Recognition ​ Leases ​ In February 2016, and further amended in 2018, the FASB issued ASC Topic 842, Leases Leases ​ We adopted ASC Topic 842 effective January 1, 2019 using the modified retrospective approach, which applied the provisions of the new guidance at the effective date without adjusting comparative periods presented. We elected a package of practical expedients permitted under the transition guidance within the new standard which allowed us to not reassess (i) whether expired or existing contracts contain a lease under the new standard, (ii) the lease classification for existing leases or (iii) whether previously-capitalized initial direct costs would qualify for capitalization under the new standard. We did not elect the hindsight practical expedient which permits entities to use hindsight in determining the lease term and assessing impairment. ​ The adoption of ASC Topic 842 impacted our consolidated balance sheets with the recognition of existing operating leases as lessee resulting in $62.9 million of ROU assets and $70.7 million of lease liabilities recorded as of January 1, 2019. We also recognized a $1.8 million cumulative effect adjustment to retained earnings. The adjustment to retained earnings was due to an impairment of certain ROU assets associated with vacant office space for which we are a lessee and assumed in a prior acquisition. See the table below for the impact of adoption of the lease standard on our consolidated balance sheets as of January 1, 2019 (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As Previously ​ New Lease Standard ​ ​ ​ ​ Reported ​ Adjustment ​ As Adjusted Operating lease right-of-use assets ​ $ — ​ $ 62,922 ​ $ 62,922 Operating lease liabilities ​ ​ — ​ ​ 70,657 ​ ​ 70,657 Deferred rent payable ​ ​ 5,922 ​ ​ (5,922) ​ ​ — ​ As lessor, accounting for our leases remained largely unchanged from ASC Topic 840. The new lease standard more narrowly defines initial direct costs as only costs that are incremental to origination of a lease (i.e. costs that would not have been incurred had the lease not been obtained). We did not historically capitalize non-incremental costs, therefore this change did not have an impact on the accounting for initial direct costs in the consolidated financial statements. ​ Additionally, from a lessor perspective, we elected a practical expedient which allows lessors to combine nonlease components with the related lease components if both the timing and pattern of transfer are the same for the nonlease component(s) and related lease component, and the lease component would be classified as an operating lease. 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. Lessors are permitted to apply the practical expedient to all existing leases on a retrospective or prospective basis. We elected the practical expedient to combine our lease and nonlease components that meet the defined criteria and account for the combined lease component under ASC Topic 842. ​ New Accounting Pronouncements ​ In August 2018, the FASB issued ASU 2018-13, Fair Value Measurement ​ In August 2018, the FASB issued ASU 2018-15, Intangibles – Goodwill and Other – Internal-Use Software ( ​ In June 2016, the FASB issued ASU 2016-13, Financial Instruments – Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments ​ In December 2019, the FASB issued ASU 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes . The amendments in this ASU simplify the accounting for income taxes by removing certain exceptions and adding some requirements regarding franchise (or similar) tax, step-ups in a business combination, treatment of entities not subject to tax and when to apply enacted changes in tax laws. This ASU is effective for fiscal years beginning after December 15, 2020 and interim periods within those fiscal years. The amendments related to changes in ownership of foreign equity method investments or foreign subsidiaries should be applied on a modified retrospective basis through a cumulative-effect adjustment to retained earnings as of the beginning of the fiscal year of adoption. The amendments related to franchise taxes that are partially based on income should be applied on either a retrospective basis for all periods presented or a modified retrospective basis through a cumulative-effect adjustment to retained earnings as of the beginning of the fiscal year of adoption. All other amendments should be applied on a prospective basis. Early adoption is permitted. We are currently assessing the impact of this standard 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, 2019
Deferred Financing Costs, Net of Accumulated Amortization	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ ​ December 31, (dollars in thousands) 2019 2018 ​ ​ ​ ​ ​ ​ ​ Deferred financing costs ​ $ 13,776 ​ $ 11,530 Accumulated amortization ​ ​ (5,743) ​ ​ (3,859) Deferred financing costs, net ​ $ 8,033 ​ $ 7,671
Deferred Leasing Costs, Net of Accumulated Amortization	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ December 31, (dollars in thousands) 2019 2018 ​ ​ ​ ​ ​ ​ ​ Deferred leasing costs ​ $ 77,178 ​ $ 63,018 Accumulated amortization ​ ​ (32,848) ​ ​ (25,593) Deferred leasing costs, net ​ $ 44,330 ​ $ 37,425
Summary of impact of adoption of the lease standard on our consolidated balance sheets	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ As Previously ​ New Lease Standard ​ ​ ​ ​ Reported ​ Adjustment ​ As Adjusted Operating lease right-of-use assets ​ $ — ​ $ 62,922 ​ $ 62,922 Operating lease liabilities ​ ​ — ​ ​ 70,657 ​ ​ 70,657 Deferred rent payable ​ ​ 5,922 ​ ​ (5,922) ​ ​ —
Fixed debt arrangements
Deferred Financing Costs, Net of Accumulated Amortization	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, ​ ​ December 31, (dollars in thousands) 2019 2018 ​ ​ ​ ​ ​ ​ ​ Deferred financing costs ​ $ 15,777 ​ $ 14,501 Accumulated amortization ​ ​ (4,937) ​ ​ (2,944) Deferred financing costs, net ​ $ 10,840 ​ $ 11,557

Acquisitions and Sales (Tables)

Acquisitions and Sales (Tables)	12 Months Ended
	Dec. 31, 2019
Acquisitions and Sales [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, 2019
Acquired Intangible Assets and Liabilities [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, 2019 ​ December 31, 2018 ​ Useful Lives Gross Accumulated Net Carrying Gross Accumulated Net Carrying Customer Relationships ​ 12 years ​ $ 95,705 ​ $ (36,411) ​ $ 59,294 ​ $ 95,705 ​ $ (28,461) ​ $ 67,244 In-Place Leases ​ 0.5 to 10 years ​ ​ 34,588 ​ ​ (22,522) ​ ​ 12,066 ​ ​ 32,066 ​ ​ (17,670) ​ ​ 14,396 Solar Power Agreement (1) ​ 17 years ​ ​ 13,747 ​ ​ (4,448) ​ ​ 9,299 ​ ​ 13,747 ​ ​ (3,639) ​ ​ 10,108 Acquired Favorable Leases ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Acquired below market leases - as Lessee ​ 46 years ​ ​ — ​ ​ — ​ ​ — ​ ​ 2,301 ​ ​ — ​ ​ 2,301 Acquired above market leases - as Lessor ​ 0.5 to 8 years ​ ​ 5,035 ​ ​ (4,015) ​ ​ 1,020 ​ ​ 4,649 ​ ​ (3,247) ​ ​ 1,402 Total Intangible Assets ​ ​ ​ $ 149,075 ​ $ (67,396) ​ $ 81,679 ​ $ 148,468 ​ $ (53,017) ​ $ 95,451 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Solar Power Agreement (1) ​ 17 years ​ ​ 13,747 ​ ​ (4,448) ​ ​ 9,299 ​ ​ 13,747 ​ ​ (3,639) ​ ​ 10,108 Acquired Unfavorable Leases ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Acquired below market leases - as Lessor ​ 3 to 4 years ​ ​ 1,092 ​ ​ (967) ​ ​ 125 ​ ​ 809 ​ ​ (611) ​ ​ 198 Acquired above market leases - as Lessee ​ 11 to 12 years ​ ​ 2,453 ​ ​ (983) ​ ​ 1,470 ​ ​ 2,453 ​ ​ (767) ​ ​ 1,686 Total Intangible Liabilities (2) ​ ​ ​ $ 17,292 ​ $ (6,398) ​ $ 10,894 ​ $ 17,009 ​ $ (5,017) ​ $ 11,992 (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 Decrease ​ Net Rental Expense Decrease 2020 $ 659 ​ $ (216) 2021 ​ 154 ​ ​ (216) 2022 ​ 52 ​ ​ (216) 2023 ​ 24 ​ ​ (216) 2024 ​ 6 ​ ​ (216) Thereafter ​ — ​ ​ (390) Total $ 895 ​ $ (1,470)
Schedule of estimated amortization of all other identified intangible assets	​ ​ ​ ​ ​ ​ ​ 2020 ​ ​ ​ $ 12,100 2021 ​ ​ ​ ​ 10,593 2022 ​ ​ ​ ​ 10,073 2023 ​ ​ ​ ​ 10,070 2024 ​ ​ ​ ​ 8,953 Thereafter ​ ​ ​ ​ 19,571 Total ​ ​ ​ $ 71,360

Real Estate Assets and Constr_2

Real Estate Assets and Construction in Progress (Tables)	12 Months Ended
	Dec. 31, 2019
Real Estate Assets and Construction in Progress [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, 2019 and 2018 (in thousands): ​ As of December 31, 2019: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Property Location Land Buildings and Improvements Construction 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) ​ ​ — ​ ​ 82,813 ​ ​ 666 ​ ​ 83,479 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) ​ ​ — ​ ​ 2,412 ​ ​ 31,840 ​ ​ 34,252 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 megascale 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 those subject to finance leases. (5) Consists of Miami, FL; Lenexa, KS; and Overland Park, KS facilities. ​ As of December 31, 2018: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Property Location Land Buildings and Construction Total Cost Atlanta, Georgia Campus( 1) ​ $ 20,416 ​ $ 493,446 ​ $ 88,253 ​ $ 602,115 Irving, Texas ​ ​ 8,606 ​ ​ 345,615 ​ ​ 99,445 ​ ​ 453,666 Richmond, Virginia ​ ​ 2,180 ​ ​ 253,098 ​ ​ 67,932 ​ ​ 323,210 Chicago, Illinois ​ ​ 9,400 ​ ​ 130,150 ​ ​ 133,095 ​ ​ 272,645 Ashburn, Virginia (2) ​ ​ 17,325 ​ ​ 63,245 ​ ​ 184,951 ​ ​ 265,521 Suwanee, Georgia (Atlanta-Suwanee) ​ ​ 3,521 ​ ​ 166,298 ​ ​ 3,188 ​ ​ 173,007 Piscataway, New Jersey ​ ​ 7,466 ​ ​ 97,806 ​ ​ 33,472 ​ ​ 138,744 Manassas, Virginia (2) (6) ​ ​ — ​ ​ — ​ ​ 45,194 ​ ​ 45,194 Santa Clara, California (3) ​ ​ — ​ ​ 98,548 ​ ​ 7,600 ​ ​ 106,148 Dulles, Virginia ​ ​ 3,154 ​ ​ 72,435 ​ ​ 3,852 ​ ​ 79,441 Fort Worth, Texas ​ ​ 9,079 ​ ​ 18,623 ​ ​ 43,715 ​ ​ 71,417 Sacramento, California ​ ​ 1,481 ​ ​ 64,874 ​ ​ 92 ​ ​ 66,447 Princeton, New Jersey ​ ​ 20,700 ​ ​ 34,046 ​ ​ 431 ​ ​ 55,177 Leased facilities (4) ​ ​ — ​ ​ 43,347 ​ ​ 9,334 ​ ​ 52,681 Hillsboro, Oregon (2) ​ ​ — ​ ​ — ​ ​ 39,835 ​ ​ 39,835 Phoenix, Arizona (2) ​ ​ — ​ ​ — ​ ​ 29,562 ​ ​ 29,562 Other (5) ​ ​ 2,213 ​ ​ 35,720 ​ ​ 113 ​ ​ 38,046 ​ ​ $ 105,541 ​ ​ 1,917,251 ​ ​ 790,064 ​ $ 2,812,856 (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 megascale 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 10 facilities. All facilities are leased, including those subject to finance leases. (5) Consists of Miami, FL; Lenexa, KS; Overland Park, KS; and Duluth, GA facilities. (6) Excludes $71.0 million of construction in progress included within the “Assets held for sale” line item of the consolidated balance sheets.

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2019
Leases [Abstract]
Schedule of components of lease expenses	Components of lease expense were as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ Year Ended ​ December 31, 2019 Finance lease cost: ​ ​ ​ Amortization of assets ​ $ 3,535 Interest on lease liabilities ​ ​ 1,693 Operating lease expense: ​ ​ ​ Operating lease cost ​ ​ 9,102 Variable lease cost ​ ​ 1,109 Sublease income ​ ​ (187) Total lease costs ​ $ 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): ​ ​ ​ ​ ​ ​ ​ December 31, ​ 2019 Operating leases: ​ ​ ​ Operating lease right-of-use assets ​ $ 57,141 Operating lease liabilities ​ ​ 64,416 Finance leases: ​ ​ ​ Property and equipment, at cost ​ ​ 50,437 Accumulated amortization ​ ​ (4,830) Property and equipment, net ​ $ 45,607 Finance lease liabilities ​ $ 45,141 ​ ​ ​ ​ Weighted average remaining lease term (in years): ​ ​ ​ Operating leases ​ ​ 13.7 Finance leases ​ ​ 11.4 ​ ​ ​ ​ Weighted average discount rate: ​ ​ ​ Operating leases ​ ​ 5.1% Finance leases ​ ​ 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, 2019 Cash paid for amounts included in the measurement of lease liabilities: ​ ​ ​ Operating cash flows for operating leases ​ $ 9,834 Operating cash flows for finance leases ​ $ 1,704 Financing cash flows for finance leases ​ $ 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, 2019 ​ Operating Leases Finance Leases 2020 $ 9,589 ​ $ 4,493 2021 ​ 9,818 ​ ​ 4,514 2022 ​ 10,266 ​ ​ 4,639 2023 ​ 10,393 ​ ​ 4,776 2024 ​ 8,317 ​ ​ 4,918 Thereafter ​ 48,908 ​ ​ 34,990 Total Lease Payments $ 97,291 ​ $ 58,330 Less: Imputed Interest ​ 32,875 ​ ​ 13,189 Total Lease Obligations $ 64,416 ​ $ 45,141
Schedule of maturities of finance lease liabilities	Maturities of lease liabilities, which exclude variable rent payments, are as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2019 ​ Operating Leases Finance Leases 2020 $ 9,589 ​ $ 4,493 2021 ​ 9,818 ​ ​ 4,514 2022 ​ 10,266 ​ ​ 4,639 2023 ​ 10,393 ​ ​ 4,776 2024 ​ 8,317 ​ ​ 4,918 Thereafter ​ 48,908 ​ ​ 34,990 Total Lease Payments $ 97,291 ​ $ 58,330 Less: Imputed Interest ​ 32,875 ​ ​ 13,189 Total Lease Obligations $ 64,416 ​ $ 45,141
Schedule of components of lease revenue	The components of our lease revenue were as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended ​ ​ December 31, ​ 2019 2018 Lease revenue: ​ ​ ​ ​ ​ ​ Minimum lease revenue ​ $ 409,157 ​ $ 367,388 Variable lease revenue (primarily recoveries from customers) ​ ​ 55,966 ​ ​ 46,232 Total lease revenue ​ $ 465,123 ​ $ 413,620

Debt (Tables)

Debt (Tables)	12 Months Ended
	Dec. 31, 2019
Debt [Abstract]
Outstanding Debt Including Capital Leases and Lease Financing Obligations	Below is a listing of our outstanding debt, including finance leases, as of December 31, 2019 and 2018 (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted Average ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Coupon Interest Rate at ​ Maturities as of ​ December 31, ​ December 31, ​ December 31, 2019 (1) December 31, 2019 2019 2018 Unsecured Credit Facility ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Revolving Credit Facility ​ 2.71% ​ December 17, 2023 ​ $ 317,028 ​ $ 252,000 Term Loan I ​ 3.16% ​ December 17, 2024 ​ ​ 225,000 ​ ​ 350,000 Term Loan II ​ 3.19% ​ April 27, 2025 ​ ​ 225,000 ​ ​ 350,000 Term Loan III ​ 3.19% ​ October 18, 2026 ​ ​ 250,000 ​ ​ — Senior Notes ​ 4.75% ​ November 15, 2025 ​ ​ 400,000 ​ ​ 400,000 Lenexa Mortgage ​ 4.10% ​ May 1, 2022 ​ ​ 1,736 ​ ​ 1,801 Finance Leases ​ 4.35% ​ 2021 - 2038 ​ ​ 45,140 ​ ​ 2,873 ​ ​ 3.54% ​ ​ ​ ​ 1,463,904 ​ ​ 1,356,674 Less net debt issuance costs ​ ​ ​ ​ ​ ​ (10,839) ​ ​ (11,557) Total outstanding debt, net ​ ​ ​ ​ ​ $ 1,453,065 ​ $ 1,345,117 (1) The coupon interest rates associated with Term Loans I - II incorporate the effects of our interest rate swaps in effect as of December 31, 2019.
Annual Remaining Principal Payment	The annual remaining principal payment requirements as of December 31, 2019 per the contractual maturities, excluding extension options and excluding operating and finance leases, are as follows (in thousands): ​ ​ ​ ​ ​ 2020 $ 64 2021 ​ ​ 73 2022 ​ ​ 1,599 2023 ​ ​ 317,028 2024 ​ ​ 225,000 Thereafter ​ ​ 875,000 Total ​ $ 1,418,764 ​

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Schedule of income tax provision from continuing operations	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the Year Ended December 31, ​ 2019 2018 2017 Current: ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. federal ​ $ — ​ $ (50) ​ $ 42 U.S. State ​ ​ 298 ​ ​ 395 ​ ​ 297 Outside United States ​ ​ 13 ​ ​ 78 ​ ​ 44 Total Current ​ ​ 311 ​ ​ 423 ​ ​ 383 Deferred: ​ ​ ​ ​ ​ ​ ​ ​ ​ U.S. federal ​ ​ (276) ​ ​ (3,727) ​ ​ (9,734) U.S. State ​ ​ (71) ​ ​ (64) ​ ​ (427) Outside United States ​ ​ (1) ​ ​ — ​ ​ — Total Deferred ​ ​ (348) ​ ​ (3,791) ​ ​ (10,161) Total ​ $ (37) ​ $ (3,368) ​ $ (9,778)
Summary of Temporary Differences and Carry Forwards Which Give Rise to the Deferred Tax Assets and Liabilities	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ For the Year Ended December 31, ​ 2019 2018 2017 Deferred tax assets ​ ​ ​ ​ ​ ​ ​ ​ ​ Net operating loss carryforwards ​ $ 20,218 ​ $ 17,610 ​ $ 8,888 Deferred revenue and setup charges ​ ​ 1,299 ​ ​ 3,171 ​ ​ 3,435 Operating lease liabilities ​ ​ 2,266 ​ ​ — ​ ​ — Property and equipment ​ ​ 512 ​ ​ — ​ ​ — Leases ​ ​ — ​ ​ 1 ​ ​ 453 Credits ​ ​ 300 ​ ​ 287 ​ ​ 543 Bad debt reserve ​ ​ 18 ​ ​ 409 ​ ​ 2,250 Intangibles ​ ​ 804 ​ ​ — ​ ​ — Interest expense carryforward IRC Sec. 163(j) ​ ​ 2,782 ​ ​ 2,253 ​ ​ — Other ​ ​ 1,376 ​ ​ 1,534 ​ ​ 1,607 Gross deferred tax assets ​ ​ 29,575 ​ ​ 25,265 ​ ​ 17,176 Deferred tax liabilities ​ ​ ​ ​ ​ ​ ​ ​ ​ Property and equipment ​ ​ — ​ ​ (3,089) ​ ​ (4,940) Goodwill ​ ​ (2,494) ​ ​ (1,953) ​ ​ (1,396) Intangibles ​ ​ (591) ​ ​ (11,910) ​ ​ (13,606) Operating lease right-of-use assets ​ ​ (1,261) ​ ​ — ​ ​ — Other ​ ​ (1,231) ​ ​ (1,049) ​ ​ (1,132) Gross deferred tax liabilities ​ ​ (5,577) ​ ​ (18,001) ​ ​ (21,074) Net deferred tax asset/(liability) ​ ​ 23,998 ​ ​ 7,264 ​ ​ (3,898) Valuation allowance ​ ​ (24,747) ​ ​ (8,361) ​ ​ (713) Net deferred tax liability ​ $ (749) ​ $ (1,097) ​ $ (4,611)
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, ​ 2019 2018 2017 TRS ​ ​ ​ ​ ​ ​ ​ ​ ​ Statutory rate applied to pre-tax loss ​ $ (12,991) ​ $ (9,656) ​ $ (5,109) Permanent differences, net ​ ​ 16 ​ ​ 97 ​ ​ (284) State income tax, net of federal benefit ​ ​ (2,868) ​ ​ (1,430) ​ ​ (388) Foreign income tax ​ ​ 13 ​ ​ 78 ​ ​ 44 Federal and State rate change ​ ​ (20) ​ ​ (146) ​ ​ (3,251) Contribution of Assets to TRS ​ ​ — ​ ​ — ​ ​ (866) Other ​ ​ (110) ​ ​ 41 ​ ​ (244) Valuation allowance increase (decrease) ​ ​ 15,923 ​ ​ 7,648 ​ ​ 320 Total tax benefit ​ $ (37) ​ $ (3,368) ​ $ (9,778) Effective tax rate ​ ​ 0.1% ​ ​ 7.3% ​ ​ 65.1%

Derivative Instruments (Tables)

Derivative Instruments (Tables)	12 Months Ended
	Dec. 31, 2019
Derivative Instruments
Schedule of interest rate derivatives and their fair values	Interest rate derivatives and their fair values as of December 31, 2019 and December 31, 2018 were as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fixed One Month ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Notional Amount ​ LIBOR rate per ​ ​ ​ ​ ​ Fair Value (1) December 31, 2019 December 31, 2018 annum Effective Date Expiration Date December 31, 2019 December 31, 2018 $ 25,000 ​ $ 25,000 ​ 1.989% ​ January 2, 2018 ​ December 17, 2021 ​ $ (209) ​ $ 331 ​ 100,000 ​ ​ 100,000 ​ 1.989% ​ January 2, 2018 ​ December 17, 2021 ​ ​ (837) ​ ​ 1,318 ​ 75,000 ​ ​ 75,000 ​ 1.989% ​ January 2, 2018 ​ December 17, 2021 ​ ​ (627) ​ ​ 990 ​ 50,000 ​ ​ 50,000 ​ 2.033% ​ January 2, 2018 ​ April 27, 2022 ​ ​ (545) ​ ​ 667 ​ 100,000 ​ ​ 100,000 ​ 2.029% ​ January 2, 2018 ​ April 27, 2022 ​ ​ (1,081) ​ ​ 1,341 ​ 50,000 ​ ​ 50,000 ​ 2.033% ​ January 2, 2018 ​ April 27, 2022 ​ ​ (545) ​ ​ 666 ​ 100,000 ​ ​ 100,000 ​ 2.617% ​ January 2, 2020 ​ December 17, 2023 ​ ​ (4,007) ​ ​ (782) ​ 100,000 ​ ​ 100,000 ​ 2.621% ​ January 2, 2020 ​ April 27, 2024 ​ ​ (4,324) ​ ​ (818) ​ 200,000 ​ ​ 200,000 ​ 2.636% ​ December 17, 2021 ​ December 17, 2023 ​ ​ (3,939) ​ ​ (722) ​ 200,000 ​ ​ 200,000 ​ 2.642% ​ April 27, 2022 ​ April 27, 2024 ​ ​ (3,802) ​ ​ (648) ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ $ (19,916) ​ $ 2,343
Schedule of power purchase agreement derivatives	Power purchase agreement derivatives and their fair values as of December 31, 2019 and December 31, 2018 were as follows (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Fair Value Counterparty ​ Facility ​ Effective Date ​ Expiration Date ​ December 31, 2019 December 31, 2018 Calpine Energy Solutions, LLC ​ Piscataway ​ 3/8/2019 ​ 2/28/2029 ​ $ (2,919) ​ $ — Calpine Energy Solutions, LLC ​ Chicago ​ 3/8/2019 ​ 2/28/2029 ​ ​ (3,774) ​ ​ — ​ ​ ​ ​ ​ ​ ​ ​ $ (6,693) ​ $ —

Partners' Capital, Equity and_2

Partners' Capital, Equity and Incentive Compensation Plans (Tables)	12 Months Ended
	Dec. 31, 2019
Partners' Capital, Equity and Incentive Compensation Plans [Abstract]
Summary of Award Activity Under 2010 Equity Incentive Plan and 2013 Equity Incentive Plan 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, 2019, 2018 and 2017: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2010 Equity Incentive Plan ​ 2013 Equity Incentive Plan ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ Restricted ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted ​ Weighted ​ ​ ​ Weighted ​ average ​ Stock / ​ Weighted ​ ​ ​ Weighted ​ ​ ​ Weighted ​ ​ ​ Number of ​ average ​ Average fair ​ ​ ​ average ​ fair ​ Deferred ​ average ​ ​ ​ average ​ ​ ​ average ​ ​ Class O units exercise price value Options exercise price value Stock grant price TSR Units grant price FFO Units grant price ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Outstanding at January 1, 2017 ​ ​ 1,134,811 ​ $ 24.06 ​ $ 3.62 ​ 1,058,297 ​ $ 31.72 ​ $ 6.51 ​ 414,691 ​ $ 40.67 ​ — ​ $ — ​ — ​ $ — Granted ​ ​ — ​ ​ — ​ ​ — ​ 468,875 ​ ​ 50.66 ​ ​ 10.32 ​ 228,576 ​ ​ 49.86 ​ — ​ ​ — ​ — ​ ​ — Exercised/Vested (1) ​ ​ (566,771) ​ ​ 24.60 ​ ​ 2.24 ​ (155,902) ​ ​ 31.89 ​ ​ 6.60 ​ (163,048) ​ ​ 40.63 ​ — ​ ​ — ​ — ​ ​ — Cancelled/Expired (2) ​ ​ — ​ ​ — ​ ​ — ​ (2,000) ​ ​ 37.69 ​ ​ 8.77 ​ (98,355) ​ ​ 39.97 ​ — ​ ​ — ​ — ​ ​ — Outstanding at December 31, 2017 ​ ​ 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 (2) ​ ​ — ​ ​ — ​ ​ — ​ — ​ ​ — ​ ​ — ​ (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 ​ ​ ​ ​ ​ 42.01 Exercised/Vested (1) ​ ​ (19,969) ​ ​ 20.25 ​ ​ 4.42 ​ (125,213) ​ ​ 30.80 ​ ​ 6.21 ​ (279,429) ​ ​ 39.20 ​ — ​ ​ — ​ — ​ ​ — Cancelled/Expired (2) ​ ​ — ​ ​ — ​ ​ — ​ (112,706) ​ ​ 45.86 ​ ​ 9.43 ​ (25,694) ​ ​ 42.17 ​ (1,739) ​ ​ ​ (1,739) ​ ​ 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 (1) This 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) Includes restricted Class A common stock surrendered by certain employees to satisfy their statutory minimum federal and state tax obligations associated with the vesting of restricted common stock.
Summary of Assumptions and Fair Values for Restricted Stock and Options to Purchase Shares of Class A Common Stock Granted	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2019 2018 2017 Fair value of FFO units and restricted stock granted ​ ​ $42.01 - $51.25 ​ ​ $34.03 - $54.01 ​ ​ $48.63 - $51.88 Fair value of TSR units granted ​ ​ $54.64 ​ ​ N/A ​ ​ N/A Fair value of options granted ​ ​ $7.56 - $8.28 ​ ​ $5.55 - $5.64 ​ ​ $10.11 - $10.36 Expected term (years) ​ ​ 5.5 ​ ​ 5.5 - 6.0 ​ ​ 5.5 - 5.9 Expected volatility ​ ​ 28% ​ ​ 28% ​ ​ 28% Expected dividend yield ​ ​ 3.89% - 4.19% ​ ​ 4.82% ​ ​ 3.08% Expected risk-free interest rates ​ ​ 2.33% - 2.56% ​ ​ 2.69% - 2.73% ​ ​ 2.12% - 2.18%
Summary of Information About Awards Outstanding	The following tables summarize information about awards outstanding as of December 31, 2019. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Operating Partnership Awards Outstanding ​ ​ ​ ​ ​ ​ ​ Weighted average ​ ​ ​ ​ ​ Awards ​ remaining ​ Exercise prices outstanding vesting period (years) Class O Units ​ $ 20.00 - 25.00 ​ 82,310 ​ — Total Operating Partnership awards outstanding ​ ​ ​ ​ 82,310 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ QTS Realty Trust, Inc. Awards Outstanding ​ ​ ​ ​ ​ ​ ​ Weighted average ​ ​ ​ ​ ​ Awards ​ remaining ​ Exercise prices outstanding vesting period (years) Restricted stock ​ $ — ​ 389,750 ​ 1.7 TSR units ​ ​ — ​ 84,350 ​ 2.0 FFO units ​ ​ — ​ 84,350 ​ 1.4 Options to purchase Class A common stock ​ $ 21.00 - 50.66 ​ 1,934,838 ​ 0.3 Total QTS Realty Trust, Inc. awards outstanding ​ ​ ​ ​ 2,493,288 ​ ​
Schedule of Quarterly Cash Dividends	​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31, 2019 ​ ​ ​ ​ ​ ​ ​ Aggregate ​ ​ ​ ​ Per Share and ​ Dividend/Distribution Record Date Payment Date Per Unit Rate Amount (in millions) Common Stock/Units ​ ​ ​ ​ ​ ​ ​ ​ 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/Units ​ ​ ​ ​ ​ ​ ​ ​ 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/Units ​ ​ ​ ​ ​ ​ ​ ​ 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 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended December 31, 2018 ​ ​ ​ ​ ​ ​ ​ Aggregate ​ ​ ​ ​ Per Share and ​ Dividend/Distribution Record Date Payment Date Per Unit Rate Amount (in millions) Common Stock/Units ​ ​ ​ ​ ​ ​ ​ ​ September 20, 2018 ​ October 4, 2018 ​ $ 0.41 ​ $ 23.7 June 20, 2018 ​ July 6, 2018 ​ ​ 0.41 ​ ​ 23.7 March 22, 2018 ​ April 5, 2018 ​ ​ 0.41 ​ ​ 23.7 December 5, 2017 ​ January 5, 2018 ​ ​ 0.39 ​ ​ 22.2 ​ ​ ​ ​ ​ ​ ​ $ 93.3 ​ ​ ​ ​ ​ ​ ​ ​ ​ Series A Preferred Stock/Units ​ ​ ​ ​ ​ ​ ​ ​ September 28, 2018 ​ October 15, 2018 ​ $ 0.45 ​ $ 1.9 June 29, 2018 ​ July 16, 2018 ​ ​ 0.45 ​ ​ 1.9 April 5, 2018 ​ April 16, 2018 ​ ​ 0.15 ​ ​ 0.6 ​ ​ ​ ​ ​ ​ ​ $ 4.4 ​ ​ ​ ​ ​ ​ ​ ​ ​ Series B Preferred Stock/Units ​ ​ ​ ​ ​ ​ ​ ​ September 30, 2018 ​ October 15, 2018 ​ $ 1.99 ​ $ 6.3 ​ ​ ​ ​ ​ ​ ​ $ 6.3 ​
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, 2019 (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Offering Program Forward Shares Settled ​ Net ​ Remaining Expected Forward Settlement (1) February 2019 Offering ​ N/A ​ 4,000 ​ ​ $ 159,360 ​ $ - ​ N/A February 2019 Offering ​ 3,763 ​ 2,832 (2) ​ ​ 109,998 ​ ​ 35,799 ​ March 31, 2020 June 2019 $400 million ATM Program ​ 2,864 ​ - ​ ​ ​ - ​ ​ 142,046 ​ Various through January 17, 2021 Total as of December 31, 2019 ​ ​ ​ ​ ​ ​ ​ ​ ​ $ 177,844 ​ ​ (1) Represents the final date which shares sold under each forward agreement may be settled. (2) Represents the number of forward shares we elected to physically settle during the year ended December 31, 2019.

Related Party Transactions (Tab

Related Party Transactions (Tables)	12 Months Ended
	Dec. 31, 2019
Related Party Transactions [Abstract]
Summary of Related Party Transactions	The transactions which occurred during the years ended December 31, 2019, 2018 and 2017 are outlined below (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, (dollars in thousands) 2019 2018 2017 Tax, utility, insurance and other reimbursement ​ $ 967 ​ $ 724 ​ $ 796 Rent expense ​ ​ 1,014 ​ ​ 1,014 ​ ​ 1,014 Capital assets acquired ​ ​ 704 ​ ​ 464 ​ ​ 561 Total ​ $ 2,685 ​ $ 2,202 ​ $ 2,371

Earnings per share of QTS Rea_2

Earnings per share of QTS Realty Trust, Inc. (Tables)	12 Months Ended
	Dec. 31, 2019
Earnings per Share [Abstract]
Summary of Basic and Diluted Earnings Per Share	The computation of basic and diluted net income per share is as follows (in thousands, except per share data): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Year Ended ​ ​ December 31, ​ 2019 2018 2017 Numerator: ​ ​ ​ ​ ​ ​ ​ ​ ​ Net income (loss) ​ $ 31,665 ​ $ (7,175) ​ $ 1,457 Loss (income) attributable to noncontrolling interests ​ ​ (374) ​ ​ 2,715 ​ ​ (175) Preferred stock dividends ​ ​ (28,180) ​ ​ (16,666) ​ ​ — Earnings attributable to participating securities ​ ​ (7,828) ​ ​ (947) ​ ​ (593) Net income (loss) available to common stockholders after allocation of participating securities ​ $ (4,717) ​ $ (22,073) ​ $ 689 Denominator: ​ ​ ​ ​ ​ ​ ​ ​ ​ Weighted average shares outstanding - basic ​ ​ 54,837 ​ ​ 50,433 ​ ​ 48,381 Effect of Class A partnership units ​ ​ — ​ ​ — ​ ​ 6,696 Effect of Class O units, TSR units and options to purchase Class A common stock on an "as if" converted basis ​ ​ — ​ ​ — ​ ​ 779 Weighted average shares outstanding - diluted ​ ​ 54,837 ​ ​ 50,433 ​ ​ 55,856 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Basic net income (loss) per share ​ $ (0.09) ​ $ (0.44) ​ $ 0.01 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Diluted net income (loss) per share ​ $ (0.09) ​ $ (0.44) ​ $ 0.01 * 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 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, ​ 2019 2018 2017 Class A Partnership units ​ ​ 6,671 ​ ​ 6,653 ​ ​ — Class O units, TSR units and options to purchase common stock on an "as if" converted basis ​ ​ 518 ​ ​ 350 ​ ​ — Series B Convertible preferred stock on an "as if" converted basis ​ ​ 6,729 ​ ​ 3,484 ​ ​ —

Contracts with Customers (Table

Contracts with Customers (Table)	12 Months Ended
	Dec. 31, 2019
Contracts with Customers [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 the practical expedient provided by 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 Ending December 31, ​ ​ 2020 $ 374,588 2021 ​ ​ 323,926 2022 ​ ​ 237,556 2023 ​ ​ 147,941 2024 ​ ​ 103,663 Thereafter ​ ​ 186,871 Total ​ $ 1,374,545

Quarterly Financial Informati_2

Quarterly Financial Information (Tables)	12 Months Ended
	Dec. 31, 2019
Summary of Selected Quarterly Information	The tables below reflect the selected quarterly information for the years ended December 31, 2019 and 2018 for QTS (in thousands except share data): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ December 31, September 30, June 30, March 31, 2019 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Revenues ​ $ 123,707 ​ $ 125,255 ​ $ 119,167 ​ $ 112,689 Operating income (loss) ​ ​ 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 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2018 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Revenues ​ $ 112,337 ​ $ 112,213 ​ $ 112,277 ​ $ 113,697 Operating income (loss) ​ ​ 12,876 ​ ​ (1,552) ​ ​ 1,882 ​ ​ 5,455 Net income (loss) ​ ​ 6,402 ​ ​ (6,892) ​ ​ (6,433) ​ ​ (252) Net income (loss) attributable to QTS Realty Trust, Inc. ​ ​ 6,476 ​ ​ (5,282) ​ ​ (5,431) ​ ​ (223) Net income (loss) attributable to common stockholders ​ ​ (569) ​ ​ (12,327) ​ ​ (7,679) ​ ​ (551) Net income (loss) per share attributable to common shares - basic ​ ​ (0.02) ​ ​ (0.25) ​ ​ (0.16) ​ ​ (0.02) Net income (loss) per share attributable to common shares - diluted ​ ​ (0.02) ​ ​ (0.25) ​ ​ (0.16) ​ ​ (0.02)
Qualitytech, LP
Summary of Selected Quarterly Information	The table below reflects the selected quarterly information for the years ended December 31, 2019 and 2018 for the Operating Partnership (in thousands): ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended ​ December 31, September 30, June 30, March 31, 2019 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Revenues ​ $ 123,707 ​ $ 125,255 ​ $ 119,167 ​ $ 112,689 Operating income (loss) ​ ​ 4,218 ​ ​ 13,606 ​ ​ 14,598 ​ ​ 28,734 Net income (loss) ​ ​ (3,606) ​ ​ 6,588 ​ ​ 7,535 ​ ​ 21,148 Net income (loss) attributable to common unitholders ​ ​ (10,651) ​ ​ (457) ​ ​ 490 ​ ​ 14,103 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2018 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Revenues ​ $ 112,337 ​ $ 112,213 ​ $ 112,277 ​ $ 113,697 Operating income (loss) ​ ​ 12,876 ​ ​ (1,552) ​ ​ 1,882 ​ ​ 5,455 Net income (loss) ​ ​ 6,402 ​ ​ (6,892) ​ ​ (6,433) ​ ​ (252) Net income (loss) attributable to common unitholders ​ ​ (643) ​ ​ (13,937) ​ ​ (8,681) ​ ​ (580)

Description of Business (Detail

Description of Business (Details)	12 Months Ended
	Dec. 31, 2019property
Organization And Description Of Business [Line Items]
Number of properties	24
QualityTech LP
Organization And Description Of Business [Line Items]
Limited Liability Company (LLC) or Limited Partnership (LP), Managing Member or General Partner, Ownership Interest	89.70%

Summary of Significant Accoun_4

Summary of Significant Accounting Policies (Narrative) (Details)	12 Months Ended
	Dec. 31, 2019USD ($)category	Dec. 31, 2018USD ($)category	Dec. 31, 2017USD ($)
Summary Of Significant Accounting Policies [Line Items]
Operating assets independent of the Operating Partnership	$ 0
Maximum exposure to losses	$ 30,200,000
Number of Revenue Categories | category	4	2
Useful life of property	40 years
Depreciation expense from operation	$ 130,800,000	$ 113,500,000	$ 104,300,000
Real estate cost capitalized excluding interest cost	17,800,000	17,400,000	12,700,000
Real estate interest cost capitalized incurred	33,200,000	26,800,000	14,300,000
Gain on sale of real estate, net	14,769,000
Gain (loss) on disposition of property	14,769,000	(6,994,000)
Reclassification from Other Revenue to Rental Income [Member]
Summary Of Significant Accounting Policies [Line Items]
Prior Period Reclassification Adjustment		7,400,000	$ 6,100,000
Reclassification from Cloud and Managed Services to Other Revenue[Member]
Summary Of Significant Accounting Policies [Line Items]
Prior Period Reclassification Adjustment		35,700,000
Qualitytech, LP
Summary Of Significant Accounting Policies [Line Items]
Operating assets independent of the Operating Partnership	0
Gain on sale of real estate, net	14,769,000
Gain (loss) on disposition of property	$ 14,769,000	(6,994,000)
Term Loan Maturing 2025
Summary Of Significant Accounting Policies [Line Items]
Interest rate			4.75%
Senior Notes 4.75 Due 2025 [Member]
Summary Of Significant Accounting Policies [Line Items]
Interest rate	4.75%
Real Estate Assets
Summary Of Significant Accounting Policies [Line Items]
Depreciation expense from operation	$ 118,900,000	101,200,000	$ 90,100,000
Non-Real Estate Assets
Summary Of Significant Accounting Policies [Line Items]
Depreciation expense from operation	$ 11,900,000	12,300,000	14,200,000
Other | Reclassification from Cloud and Managed Services to Other Revenue[Member]
Summary Of Significant Accounting Policies [Line Items]
Prior Period Reclassification Adjustment			65,500,000
Other | Reclassification Other Revenue [Member]
Summary Of Significant Accounting Policies [Line Items]
Prior Period Reclassification Adjustment			1,200,000
Recoveries From Customers
Summary Of Significant Accounting Policies [Line Items]
Prior Period Reclassification Adjustment		45,400,000	$ 37,900,000
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
Maximum | Other | Reclassification Other Revenue [Member]
Summary Of Significant Accounting Policies [Line Items]
Prior Period Reclassification Adjustment		1,200,000
Restructuring Charges.
Summary Of Significant Accounting Policies [Line Items]
Gain (loss) on disposition of property		$ (7,000,000)
Atlanta Metro facility
Summary Of Significant Accounting Policies [Line Items]
Gain on sale of real estate, net	$ 1,400,000
Owned Properties | Manassas, Virginia
Summary Of Significant Accounting Policies [Line Items]
Transaction cost	5,800,000
Gain on sale of real estate, net	$ 13,400,000

Summary of Significant Accoun_5

Summary of Significant Accounting Policies (Additional Information 1) (Details) $ in Thousands	1 Months Ended	12 Months Ended
	Oct. 31, 2019	Dec. 31, 2019USD ($)item	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)
Summary Of Significant Accounting Policies [Line Items]
Number of Reporting Units | item		1
Assets held for sale			$ 71,800
Liabilities held for sale			24,349
Amortization of the deferred financing costs		$ 3,877	3,856	$ 3,640
Write off of deferred loan costs		1,532	605	80
Amortization of deferred leasing costs		24,200	21,300	18,500
Aggregate allowance for doubtful accounts		2,300	3,800
Deferred income		39,169	33,241	25,300
Amortization of deferred revenue		$ 15,200	12,500	10,700
Equity based compensation associated with the acceleration of equity awards			3,100
Practical Expedient, remaining term		true
Unsecured Revolving Credit Facility
Summary Of Significant Accounting Policies [Line Items]
Amortization of the deferred financing costs		$ 3,900	3,900	3,600
Write off of deferred loan costs				5,200
Term Loan Maturing 2022 Member
Summary Of Significant Accounting Policies [Line Items]
Debt Instrument Face Amount				$ 300,000
Interest rate				5.875%
Term Loan Maturing 2025
Summary Of Significant Accounting Policies [Line Items]
Debt Instrument Face Amount				$ 400,000
Interest rate				4.75%
Transaction Integration And Impairment Costs
Summary Of Significant Accounting Policies [Line Items]
Impairment losses		11,500		$ 1,600
Restructuring Charges.
Summary Of Significant Accounting Policies [Line Items]
Impairment losses			8,800
Company recorded equity-based compensation expense net of repurchased awards and forfeits		$ 16,400	15,000	$ 13,900
Cloud and managed services | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-01-01
Summary Of Significant Accounting Policies [Line Items]
Remaining term		3 years
Assets Held For Sale
Summary Of Significant Accounting Policies [Line Items]
Assets held for sale			71,800
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		$ 38,700	29,700
Liabilities Held For Sale
Summary Of Significant Accounting Policies [Line Items]
Liabilities held for sale			$ 24,300
Unsecured Credit Facility Two | Revolving Credit Facility Maturing December 17 2023
Summary Of Significant Accounting Policies [Line Items]
Loan term	7 years

Summary of Significant Accoun_6

Summary of Significant Accounting Policies (Deferred Financing Costs, Net of Accumulated Amortization) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Deferred financing costs	$ 13,776	$ 11,530
Accumulated amortization	(5,743)	(3,859)
Deferred financing costs, net	8,033	7,671
Fixed debt arrangements
Deferred financing costs	15,777	14,501
Accumulated amortization	(4,937)	(2,944)
Deferred financing costs, net	$ 10,840	$ 11,557

Summary of Significant Accoun_7

Summary of Significant Accounting Policies (Deferred Leasing Costs, Net of Accumulated Amortization) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Summary of Significant Accounting Policies [Abstract]
Deferred leasing costs	$ 77,178	$ 63,018
Accumulated amortization	(32,848)	(25,593)
Deferred leasing costs, net	$ 44,330	$ 37,425

Summary of Significant Accoun_8

Summary of Significant Accounting Policies (Additional Information 2) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2019USD ($)segment	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)
Summary Of Significant Accounting Policies [Line Items]
Number of operating segments | segment	1
Number of reportable segments | segment	1
Unrecognized Tax Benefits | $	$ 0	$ 0	$ 0
Interest and penalties related to income taxes | $	$ 0	$ 0	$ 0
Lease, Practical Expedients, Package [true/false]	true
Lease, Practical Expedient, Use of Hindsight [true/false]	false
Minimum Quarterly Distribution Of Available Cash	100.00%
Customer One | Rental Revenue
Summary Of Significant Accounting Policies [Line Items]
Percentage of total revenue	14.00%
No Other Customers | Accounts Receivable | Minimum
Summary Of Significant Accounting Policies [Line Items]
Percentage of trade accounts receivable	10.00%
Five Customers | Accounts Receivable
Summary Of Significant Accounting Policies [Line Items]
Percentage of trade accounts receivable	30.00%
Five 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	Jan. 01, 2019
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease right-of-use assets, net	$ 57,141
Operating lease liabilities	64,416
ASC 842
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease right-of-use assets, net		$ 62,922
Operating lease liabilities		70,657
ASC 842 | As Previously Reported
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Deferred rent payable		5,922
ASC 842 | New Lease Standard Adjustment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect adjustment to retained earnings	$ 1,800
Operating lease right-of-use assets, net		62,922
Operating lease liabilities		70,657
Deferred rent payable		$ (5,922)

Acquisitions and Sales (Narrati

Acquisitions and Sales (Narrative) (Details) $ in Millions	Apr. 23, 2019USD ($)ft²itemMW
Acquisitions and Sales [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, 2019	Dec. 31, 2018	Dec. 31, 2017
Acquisitions and Sales [Abstract]
Land	$ 1,743	$ 1,743		$ 9,363
Buildings and improvements	8,640	8,640	$ 445	14,341
Construction in Progress	29,902	61,514	$ 114,283	$ 103,334
Acquired intangibles (In-place lease & above market lease)	2,911
Deferred costs	906
Other assets	128	$ 128
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

Acquisitions and Sales (Land Pa

Acquisitions and Sales (Land Parcels) (Details) $ in Millions	1 Months Ended				12 Months Ended
	Nov. 30, 2019USD ($)a	Jul. 31, 2019USD ($)a	Apr. 30, 2019USD ($)a	Oct. 31, 2018USD ($)a	Dec. 31, 2018USD ($)a	Dec. 31, 2019
Atlanta DC Two Facility
Property, Plant and Equipment [Line Items]
Acres of land | a			4
Payments to Acquire Land			$ 2.2
Atlanta DC One Facility
Property, Plant and Equipment [Line Items]
Acres of land | a				55
Payments to Acquire Land				$ 80.1
Land in Ashburn, Virginia
Property, Plant and Equipment [Line Items]
Acres of land | a		28
Payments to Acquire Land		$ 22.4
Land in Richmond, Virginia
Property, Plant and Equipment [Line Items]
Acres of land | a	75
Payments to Acquire Land	$ 7
Land in Manassas, Virginia | Construction in Progress
Property, Plant and Equipment [Line Items]
Acres of land | a					118
Payments to Acquire Land					$ 37
Atlanta Building Sale
Property, Plant and Equipment [Line Items]
Gain on sale of property	$ 1.4
Lessor, Operating Lease, Term of Contract						20 years

Acquired Intangibles Assets a_2

Acquired Intangibles Assets and Liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Finite-lived intangible assets
Gross Carrying Value	$ 149,075	$ 148,468
Accumulated Amortization	(67,396)	(53,017)
Net Carrying Value	81,679	95,451
Acquired Intangible Liabilities
Acquired intangible liabilities	17,292	17,009
Accumulated Amortization	(6,398)	(5,017)
New Carrying Value	$ 10,894	$ 11,992
Customer Relationships
Finite-lived intangible assets
Useful Lives	12 years	12 years
Gross Carrying Value	$ 95,705	$ 95,705
Accumulated Amortization	(36,411)	(28,461)
Net Carrying Value	59,294	67,244
In Place Leases
Finite-lived intangible assets
Gross Carrying Value	34,588	32,066
Accumulated Amortization	(22,522)	(17,670)
Net Carrying Value	$ 12,066	$ 14,396
In Place Leases | Minimum
Finite-lived intangible assets
Useful Lives	6 months	6 months
In Place Leases | Maximum
Finite-lived intangible assets
Useful Lives	10 years	10 years
Solar Power Agreement
Finite-lived intangible assets
Useful Lives	17 years	17 years
Gross Carrying Value	$ 13,747	$ 13,747
Accumulated Amortization	(4,448)	(3,639)
Net Carrying Value	$ 9,299	$ 10,108
Below Market Leases As Lessee
Finite-lived intangible assets
Useful Lives	46 years	46 years
Acquired below market leases - as Lessor
Gross Carrying Value		$ 2,301
Net Carrying Value		2,301
Above Market Leases As Lessor
Acquired above market leases - as Lessee
Gross Carrying Value	$ 5,035	4,649
Accumulated Amortization	(4,015)	(3,247)
Net Carrying Value	$ 1,020	$ 1,402
Above Market Leases As Lessor | Minimum
Finite-lived intangible assets
Useful Lives	6 months	6 months
Above Market Leases As Lessor | Maximum
Finite-lived intangible assets
Useful Lives	8 years	8 years
Below Market Leases As Lessor
Acquired below market leases - as Lessor
Gross Carrying Value	$ 1,092	$ 809
Accumulated Amortization	(967)	(611)
Net Carrying Value	$ 125	$ 198
Below Market Leases As Lessor | Minimum
Finite-lived intangible assets
Useful Lives	3 years	3 years
Below Market Leases As Lessor | Maximum
Finite-lived intangible assets
Useful Lives	4 years	4 years
Above Market Lease As Lessee
Acquired above market leases - as Lessee
Gross Carrying Value	$ 2,453	$ 2,453
Accumulated Amortization	(983)	(767)
Net Carrying Value	$ 1,470	$ 1,686
Above Market Lease As Lessee | Minimum
Finite-lived intangible assets
Useful Lives	11 years	11 years
Above Market Lease As Lessee | Maximum
Finite-lived intangible assets
Useful Lives	12 years	12 years

Acquired Intangibles Assets a_3

Acquired Intangibles Assets and Liabilities - Amortization (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Amortization of acquired above and below-market leases, net	$ 187	$ 465	$ 865
Amortization of all other identified intangible assets	13,200	15,000	$ 18,200
Estimated amortization of all other identified intangible assets
Net Carrying Value	81,679	$ 95,451
Acquired favorable and unfavorable leases
Estimated amortization of acquired favorable and unfavorable leases Rental Revenue
2020	659
2021	154
2022	52
2023	24
2024	6
Total	895
Estimated amortization of acquired favorable and unfavorable leases Rental Expense
2020	(216)
2021	(216)
2022	(216)
2023	(216)
2024	(216)
Thereafter	(390)
Total	(1,470)
All other identified intangible assets
Estimated amortization of all other identified intangible assets
2020	12,100
2022	10,593
2023	10,073
2024	10,070
2023	8,953
Thereafter	19,571
Net Carrying Value	$ 71,360

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, 2019USD ($)property	Dec. 31, 2018USD ($)property
Real Estate Properties [Line Items]
Land	$ 130,605	$ 105,541
Buildings, Improvements and Equipment	2,178,901	1,917,251
Construction in progress	920,922	790,064
Total cost	3,230,428	2,812,856
Manassas, Virginia | Assets Held For Sale
Real Estate Properties [Line Items]
Construction in progress	71,000
Owned Properties | Atlanta, Georgia Campus
Real Estate Properties [Line Items]
Land	44,588	20,416
Buildings, Improvements and Equipment	525,300	493,446
Construction in progress	128,930	88,253
Total cost	698,818	602,115
Owned Properties | Irving, Texas
Real Estate Properties [Line Items]
Land	8,606	8,606
Buildings, Improvements and Equipment	369,727	345,615
Construction in progress	98,170	99,445
Total cost	476,503	453,666
Owned Properties | Richmond, Virginia
Real Estate Properties [Line Items]
Land	2,180	2,180
Buildings, Improvements and Equipment	195,684	253,098
Construction in progress	139,948	67,932
Total cost	337,812	323,210
Owned Properties | Chicago, Illinois
Real Estate Properties [Line Items]
Land	9,400	9,400
Buildings, Improvements and Equipment	205,026	130,150
Construction in progress	86,878	133,095
Total cost	301,304	272,645
Owned Properties | Ashburn, Virginia
Real Estate Properties [Line Items]
Land	16,476	17,325
Buildings, Improvements and Equipment	156,396	63,245
Construction in progress	189,375	184,951
Total cost	362,247	265,521
Owned Properties | Suwanee, Georgia (Atlanta-Suwanee)
Real Estate Properties [Line Items]
Land	3,521	3,521
Buildings, Improvements and Equipment	174,124	166,298
Construction in progress	5,559	3,188
Total cost	183,204	173,007
Owned Properties | Piscataway New Jersey
Real Estate Properties [Line Items]
Land	7,466	7,466
Buildings, Improvements and Equipment	103,553	97,806
Construction in progress	36,056	33,472
Total cost	147,075	138,744
Owned Properties | Manassas, Virginia
Real Estate Properties [Line Items]
Construction in progress	57,662	45,194
Total cost	57,662	45,194
Owned Properties | Santa Clara, California
Real Estate Properties [Line Items]
Buildings, Improvements and Equipment	114,499	98,548
Construction in progress	1,238	7,600
Total cost	115,737	106,148
Owned Properties | Dulles, Virginia
Real Estate Properties [Line Items]
Land	3,154	3,154
Buildings, Improvements and Equipment	48,651	72,435
Construction in progress	4,688	3,852
Total cost	56,493	79,441
Owned Properties | Fort Worth, Texas
Real Estate Properties [Line Items]
Land	9,079	9,079
Buildings, Improvements and Equipment	55,018	18,623
Construction in progress	35,722	43,715
Total cost	99,819	71,417
Owned Properties | Sacramento, California
Real Estate Properties [Line Items]
Land	1,481	1,481
Buildings, Improvements and Equipment	65,258	64,874
Construction in progress	163	92
Total cost	66,902	66,447
Owned Properties | Princeton, New Jersey
Real Estate Properties [Line Items]
Land	20,700	20,700
Buildings, Improvements and Equipment	35,192	34,046
Construction in progress	39	431
Total cost	55,931	55,177
Owned Properties | Hillsboro, Oregon
Real Estate Properties [Line Items]
Construction in progress	63,573	39,835
Total cost	63,573	39,835
Owned Properties | Phoenix, Arizona
Real Estate Properties [Line Items]
Buildings, Improvements and Equipment	2,412
Construction in progress	31,840	29,562
Total cost	34,252	29,562
Owned Properties | Eemshaven, Netherlands
Real Estate Properties [Line Items]
Construction in progress	37,267
Total cost	37,267
Owned Properties | Groningen, Netherlands
Real Estate Properties [Line Items]
Land	2,213
Buildings, Improvements and Equipment	36,163
Construction in progress	120
Total cost	38,496
Owned Properties | Other
Real Estate Properties [Line Items]
Land		2,213
Buildings, Improvements and Equipment		35,720
Construction in progress		113
Total cost		38,046
Leased Properties
Real Estate Properties [Line Items]
Buildings, Improvements and Equipment	82,813	43,347
Construction in progress	666	9,334
Total cost	$ 83,479	$ 52,681
Number of facilities leased | property	7
Leased Properties
Real Estate Properties [Line Items]
Number of facilities leased | property		10

Leases - Finance leases (Detail

Leases - Finance leases (Details)	12 Months Ended
	Dec. 31, 2019item
Lease as Lessee
Number of finance leases	1
Options to extend - finance leases	true
Minimum
Lease as Lessee
Remaining terms - finance leases	1 year
Maximum
Lease as Lessee
Remaining terms - finance leases	18 years

Leases - Operating leases (Deta

Leases - Operating leases (Details)	12 Months Ended
	Dec. 31, 2019item
Lease as Lessee
Options to extend - operating leases	true
Number of ground leases under operating leases	1
Minimum
Lease as Lessee
Remaining terms - operating leases	4 years
Maximum
Lease as Lessee
Remaining terms - operating leases	7 years

Leases - Components of lease ex

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

Leases - Supplemental balance s

Leases - Supplemental balance sheet information (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Lease as Lessee
Operating lease right-of-use assets	$ 57,141
Operating lease liabilities	64,416
Property and equipment, at cost	3,230,428	$ 2,812,856
Accumulated amortization	(558,560)	(467,644)
Real Estate Assets, net	2,671,868	$ 2,345,212
Finance lease liabilities	45,141
Finance leased assets
Lease as Lessee
Operating lease right-of-use assets	57,141
Operating lease liabilities	64,416
Property and equipment, at cost	50,437
Accumulated amortization	(4,830)
Real Estate Assets, net	$ 45,607

Leases - Other information (Det

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

Leases - Supplemental cash flow

Leases - Supplemental cash flow and other information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Leases [Abstract]
Operating cash flows from operating leases	$ 9,834
Operating cash flows from finance leases	1,704
Financing cash flows from finance leases	$ 2,855	$ 7,626	$ 12,224

Leases - Maturities of lease li

Leases - Maturities of lease liabilities (Details) $ in Thousands	Dec. 31, 2019USD ($)
Operating Leases Maturities:
2020	$ 9,589
2021	9,818
2022	10,266
2023	10,393
2024	8,317
Thereafter	48,908
Total Lease Payments	97,291
Less: Imputed Interest	32,875
Total Lease Obligations	64,416
Finance Leases Maturities:
2020	4,493
2021	4,514
2022	4,639
2023	4,776
2024	4,918
Thereafter	34,990
Total Lease Payments	58,330
Less: Imputed Interest	13,189
Total Lease Obligations	$ 45,141

Leases - Leases as lessor (Deta

Leases - Leases as lessor (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Lease revenue:
Minimum lease revenue	$ 409,157	$ 367,388
Variable lease revenue (primarily recoveries from customers)	55,966	46,232
Total lease revenue	$ 465,123	$ 413,620	$ 379,787

Investments in Unconsolidated_2

Investments in Unconsolidated Entity (Details) - Joint venture with Alinda $ in Millions	Dec. 31, 2019USD ($)
Investments in Unconsolidated Joint Ventures
Lease term of facility with global cloud-based software company	10 years
Equity method investments	$ 30.2
Ownership interest (as a percent)	50.00%
Assets	$ 127.8
Debt outstanding, net of deferred financing costs	$ 68.2

Debt (Outstanding Debt Includin

Debt (Outstanding Debt Including Capital Leases) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Weighted average coupon interest rate	3.54%
Total debt and lease obligations	$ 1,463,904	$ 1,356,674
Less net debt issuance costs	(10,839)	(11,557)
Total outstanding debt, net	$ 1,453,065	1,345,117
Unsecured Revolving Credit Facility | Unsecured Revolving Credit Facility
Debt Instrument [Line Items]
Weighted average coupon interest rate	2.71%
Maturity date	Dec. 17, 2023
Outstanding debt	$ 317,028	252,000
Term Loan I | Term Loan I
Debt Instrument [Line Items]
Weighted average coupon interest rate	3.16%
Maturity date	Dec. 17, 2024
Outstanding debt	$ 225,000	350,000
Term Loan II | Term Loan II
Debt Instrument [Line Items]
Weighted average coupon interest rate	3.19%
Maturity date	Apr. 27, 2025
Outstanding debt	$ 225,000	350,000
Term Loan III | Term Loan III
Debt Instrument [Line Items]
Weighted average coupon interest rate	3.19%
Maturity date	Oct. 18, 2026
Outstanding debt	$ 250,000
Operating Partnership And QTS Finance Corporation
Debt Instrument [Line Items]
Weighted average coupon interest rate	4.75%
Maturity date	Nov. 15, 2025
Outstanding debt	$ 400,000	400,000
Lenexa Mortgage | Lenexa Mortgage
Debt Instrument [Line Items]
Weighted average coupon interest rate	4.10%
Maturity date	May 1, 2022
Outstanding debt	$ 1,736	1,801
Finance Leases | Finance Leases
Debt Instrument [Line Items]
Weighted average coupon interest rate	4.35%
Maturity date description	2021 - 2038
Outstanding debt	$ 45,140	$ 2,873

Debt (Unsecured Credit Facility

Debt (Unsecured Credit Facility Narrative) (Details) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Oct. 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Debt issuance costs, net		$ 8,033	$ 7,671
Debt Weighted Average Interest Rate		3.54%
Unsecured Credit Facility Two
Debt Instrument [Line Items]
Debt Instrument, Covenant Compliance		we were in compliance with all of our covenants
Operating Partnership And QTS Finance Corporation
Debt Instrument [Line Items]
Maturity date		Nov. 15, 2025
Outstanding debt		$ 400,000	$ 400,000
Debt Weighted Average Interest Rate		4.75%
Unsecured Credit Facility Two
Debt Instrument [Line Items]
Outstanding debt		$ 1,017,000
Unsecured Credit Facility Two | Term Loan
Debt Instrument [Line Items]
Outstanding debt		700,000
Debt issuance costs, net		6,400
Unsecured Credit Facility Two | Term Loan A Maturing December 17 2024
Debt Instrument [Line Items]
Credit facility maximum borrowing capacity	$ 225,000
Maturity date	Dec. 17, 2024
Unsecured Credit Facility Two | Term Loan B Maturing April 27 2025
Debt Instrument [Line Items]
Credit facility maximum borrowing capacity	$ 225,000
Maturity date	Apr. 27, 2025
Unsecured Credit Facility Two | Term Loan C Maturing October 18 2026
Debt Instrument [Line Items]
Credit facility maximum borrowing capacity	$ 250,000
Maturity date	Oct. 18, 2026
Unsecured Credit Facility Two | Unsecured Revolving Credit Facility
Debt Instrument [Line Items]
Outstanding debt		317,000
Unsecured Credit Facility Two | Revolving Credit Facility Maturing December 17 2023
Debt Instrument [Line Items]
Credit facility maximum borrowing capacity	$ 1,000,000			$ 1,700,000
Debt extension period	1 year
Maturity date	Dec. 17, 2023
Additional contingent borrowing capacity, maximum				$ 2,200,000
Unsecured Credit Facility Two | Letter of Credit [Member]
Debt Instrument [Line Items]
Letter of credit outstanding		$ 4,000
Line of credit facility weighted average interest rate outstanding percentage		3.03%
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%
Unsecured Credit Facility Two | Maximum | Various Foreign Currency
Debt Instrument [Line Items]
Credit facility maximum borrowing capacity	$ 300,000

Debt (Senior Notes) (Details)

Debt (Senior Notes) (Details) - USD ($) $ in Thousands	Nov. 08, 2017	Dec. 31, 2019	Dec. 31, 2018	Jul. 23, 2014
Debt Instrument [Line Items]
Deferred Finance Costs Net		$ 8,033	$ 7,671
Operating Partnership And QTS Finance Corporation
Debt Instrument [Line Items]
Senior notes due	2022
Maturity date		Nov. 15, 2025
Senior Notes. | Operating Partnership And QTS Finance Corporation
Debt Instrument [Line Items]
Aggregate principal amount	$ 400,000
Interest rate	4.75%			5.875%
Deferred Finance Costs Net		$ 4,500
Percentage of issued price equal to face value	100.00%

Debt (Annual Remaining Principa

Debt (Annual Remaining Principal Payment) (Details) $ in Thousands	Dec. 31, 2019USD ($)
Debt [Abstract]
2020	$ 64
2021	73
2022	1,599
2023	317,028
2024	225,000
Thereafter	875,000
Total	$ 1,418,764

Income Taxes - Components of In

Income Taxes - Components of Income tax Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Current:
U.S. federal		$ (50)	$ 42
U.S. State	$ 298	395	297
Outside United States	13	78	44
Total Current	311	423	383
Deferred:
U.S. federal	(276)	(3,727)	(9,734)
U.S. State	(71)	(64)	(427)
Outside United States	(1)
Total Deferred	(348)	(3,791)	(10,161)
Total	$ (37)	$ (3,368)	$ (9,778)

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, 2019	Dec. 31, 2018	Dec. 31, 2017
Deferred tax assets
Net operating loss carryforwards	$ 20,218	$ 17,610	$ 8,888
Deferred revenue and setup charges	1,299	3,171	3,435
Operating lease liabilities	2,266
Property and equipment	512
Leases		1	453
Credits	300	287	543
Bad debt reserve	18	409	2,250
Intangibles	804
Interest expense carryforward IRC Sec. 163(j)	2,782	2,253
Other	1,376	1,534	1,607
Gross deferred tax assets	29,575	25,265	17,176
Deferred tax liabilities
Property and equipment		(3,089)	(4,940)
Goodwill	(2,494)	(1,953)	(1,396)
Intangibles	(591)	(11,910)	(13,606)
Operating lease right-of-use assets	(1,261)
Other	(1,231)	(1,049)	(1,132)
Gross deferred tax liabilities	(5,577)	(18,001)	(21,074)
Net deferred tax asset/(liability)	23,998	7,264	(3,898)
Valuation allowance	(24,747)	(8,361)	(713)
Net deferred tax liability	$ (749)	$ (1,097)	$ (4,611)

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, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Statutory rate applied to pre-tax loss	$ (12,991)	$ (9,656)	$ (5,109)
Permanent differences, net	16	97	(284)
State income tax, net of federal benefit	(2,868)	(1,430)	(388)
Foreign income tax	13	78	44
Federal and State rate change	(20)	(146)	(3,251)
Contribution of Assets to TRS			(866)
Other	(110)	41	(244)
Valuation allowance increase (decrease)	15,923	7,648	320
Total tax benefit	$ (37)	$ (3,368)	$ (9,778)
Effective tax rate	0.10%	7.30%	65.10%
Statutory rate	21.00%	21.00%	35.00%

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019USD ($)entity	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)
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	39,900
Net operating loss carry forwards related to State income taxes	78,400
Interest expense carryforward with no expiration	10,900
One-time non-cash income tax benefit of $3.3 million to reflect the re-measurement of deferred tax assets (liabilities)			$ 3,300
Deferred Tax Assets, Tax Credit Carryforwards, Alternative Minimum Tax	300
Unrecognized Tax Benefits	0	$ 0	0
Interest and penalties related to income taxes	0	0	0
Valuation allowance	24,747	$ 8,361	$ 713
Deferred Tax Assets Valuation Allowance Change	$ 16,300
Federal [Member] | Maximum
Net operating loss carry forwards, expiration period	17 years
Federal [Member] | Minimum
Net operating loss carry forwards, expiration period	10 years
State [Member] | Maximum
Net operating loss carry forwards, expiration period	20 years
State [Member] | Minimum
Net operating loss carry forwards, expiration period	1 year

Derivative Instruments (Details

Derivative Instruments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 20, 2018	Apr. 05, 2017
Derivative [Line Items]
Interest expense related to payments on interest rate swaps	$ 26,593	$ 28,749	$ 30,523
Increase (decrease) in fair value of derivative contracts	(29,843)	895	1,449
Interest Rate Swap
Derivative [Line Items]
Derivative instruments, notional amount					$ 400,000
Ineffectiveness recognized	0	0	$ 0
Interest Rate Swap | Term Loan I
Derivative [Line Items]
Aggregate principal amount					400,000
Expiration December 17 2021 [Member] | Term Loan I
Derivative [Line Items]
Derivative instruments, notional amount					200,000
Expiration April 27 2022 [Member] | Term Loan I
Derivative [Line Items]
Derivative instruments, notional amount					$ 200,000
Interest Rate Swap Two [Member]
Derivative [Line Items]
Derivative instruments, notional amount				$ 400,000
Interest Rate Swap Two [Member] | Term Loan
Derivative [Line Items]
Aggregate principal amount				400,000
Expiration December 17 2023 [Member] | Term Loan II
Derivative [Line Items]
Derivative instruments, notional amount				200,000
Expiration April 27 2024 [Member] | Term Loan II
Derivative [Line Items]
Derivative instruments, notional amount				200,000
Interest Rate Swap Three [Member] | Term Loan III
Derivative [Line Items]
Derivative instruments, notional amount				200,000
Expiration Dec 17 2023 [Member] | Term Loan III
Derivative [Line Items]
Aggregate principal amount				100,000
Expiration Apr 27 2024 [Member] | Term Loan III
Derivative [Line Items]
Aggregate principal amount				$ 100,000
Cash flow hedging | Interest Rate Swap
Derivative [Line Items]
Derivative Asset, fair Value		5,300
Derivative Liability, fair Value	19,900	3,000
Derivative, Fair Value, Net	$ (19,916)	$ 2,343

Derivative Instruments - Intere

Derivative Instruments - Interest rate derivatives and their fair values (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Apr. 05, 2017
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Reclassification of other comprehensive income to interest expense		$ (1,000)	$ 100	$ 0
Forecast
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Reclassification of other comprehensive income to interest expense	$ (3,600)
Interest Rate Swap
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional amount of derivative					$ 400,000
Interest Rate Swap | Cash flow hedging
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Fair value		(19,916)	2,343
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	25,000
Fixed Rate Per annum		1.989%
Expiration Date		Dec. 17, 2021
Fair value		$ (209)	331
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	100,000
Fixed Rate Per annum		1.989%
Expiration Date		Dec. 17, 2021
Fair value		$ (837)	1,318
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	75,000
Fixed Rate Per annum		1.989%
Expiration Date		Dec. 17, 2021
Fair value		$ (627)	990
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	50,000
Fixed Rate Per annum		2.033%
Expiration Date		Apr. 27, 2022
Fair value		$ (545)	667
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	100,000
Fixed Rate Per annum		2.029%
Expiration Date		Apr. 27, 2022
Fair value		$ (1,081)	1,341
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	50,000
Fixed Rate Per annum		2.033%
Expiration Date		Apr. 27, 2022
Fair value		$ (545)	666
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	100,000
Fixed Rate Per annum		2.617%
Expiration Date		Dec. 17, 2023
Fair value		$ (4,007)	(782)
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	100,000
Fixed Rate Per annum		2.621%
Expiration Date		Apr. 27, 2024
Fair value		$ (4,324)	(818)
Swap instrument two matures on December 17, 2023
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional amount of derivative		$ 200,000	200,000
Fixed Rate Per annum		2.636%
Expiration Date		Dec. 17, 2023
Fair value		$ (3,939)	(722)
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	200,000
Fixed Rate Per annum		2.642%
Expiration Date		Apr. 27, 2024
Fair value		$ (3,802)	$ (648)

Derivative Instruments - Power

Derivative Instruments - Power Purchase Agreements (Details) $ in Thousands	1 Months Ended	12 Months Ended
	Mar. 31, 2019agreement	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)
Derivative [Line Items]
Increase In Utilities Expense		$ 700
Reclassification of other comprehensive income to utilities expense		(749)	$ 0	$ 0
Fair value		$ (6,693)
Piscataway | Calpine Energy Solutions, LLC
Derivative [Line Items]
Expiration Date		Feb. 28, 2029
Fair value		$ (2,919)
Chicago | Calpine Energy Solutions, LLC
Derivative [Line Items]
Expiration Date		Feb. 28, 2029
Fair value		$ (3,774)
Chicago And Piscataway | Power Purchase Agreements
Derivative [Line Items]
Number of agreements | agreement	2
Term of agreement	10 years

Partners' Capital, Equity and_3

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

Feb. 18, 2020

Jan. 15, 2020$ / shares

May 08, 2019shares

Oct. 15, 2018$ / shares

Jun. 25, 2018

Apr. 16, 2018$ / shares

Mar. 15, 2018

May 04, 2017USD ($)itemshares

May 04, 2015shares

Mar. 31, 2019

Dec. 31, 2019USD ($)Partnershipitemshares

Dec. 31, 2017USD ($)

May 09, 2019shares

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 | $

$ 17,000,000

Equity based compensation expense vesting period

1 year 1 month 6 days

Preferred Stock, Dividend Rate, Percentage

7.125%

Proceeds net of fees from common equity offering | $

$ 158,663,000

$ 107,495,000

Subsequent Event

Partners Capital And Distributions [Line Items]

Dividends payable, date payable

Apr. 7, 2020

QTS Realty Trust, Inc. Employee Stock Purchase Plan

Partners Capital And Distributions [Line Items]

Shares reserved for purchase under plan

250,000

2017 Plan

Partners Capital And Distributions [Line Items]

Minimum period of service

30 days

Minimum hours per week of service | item

30

Purchase period per year | item

4

Class O Units

Partners Capital And Distributions [Line Items]

Equity based compensation awards intrinsic value | $

$ 35,400,000

Class B Common Stock

Partners Capital And Distributions [Line Items]

Number of votes per share | item

50

Class A Common Stock | 2017 Plan

Partners Capital And Distributions [Line Items]

Shares reserved for purchase under plan

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 dividends per share cash paid | $ / shares

$ 0.14844

Series A Redeemable Perpetual Preferred | Subsequent Event

Partners Capital And Distributions [Line Items]

Dividend paid to common stockholders | $ / shares

$ 0.45

Dividends payable, date payable

Jan. 15, 2020

Series B Convertible preferred stock [Member]

Partners Capital And Distributions [Line Items]

Preferred stock dividends per share cash paid | $ / shares

$ 1.9861111

Preferred Stock, Dividend Rate, Percentage

6.50%

Series B Convertible preferred stock [Member] | Subsequent Event

Partners Capital And Distributions [Line Items]

Dividend paid to common stockholders | $ / shares

$ 1.63

Dividends payable, date payable

Jan. 15, 2020

Preferred Units Series A [Member] | Subsequent Event

Partners Capital And Distributions [Line Items]

Dividend paid to common stockholders | $ / shares

$ 0.45

Preferred Units Series B [Member] | Subsequent Event

Partners Capital And Distributions [Line Items]

Dividend paid to common stockholders | $ / shares

$ 1.63

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

5.00%

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

Restricted Class A Common Stock

Partners Capital And Distributions [Line Items]

Options outstanding

600,000

Performance-Based FFO Units

Partners Capital And Distributions [Line Items]

Nonvested awards outstanding

84,350

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%

Performance-Based Relative TSR Units

Partners Capital And Distributions [Line Items]

Vesting period

3 years

Nonvested awards outstanding

84,350

Performance-Based Relative TSR Units | Minimum | Class A Common Stock

Partners Capital And Distributions [Line Items]

Percentage of target award

0.00%

Performance-Based Relative TSR 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

5,860,000

1,750,000

Additional shares available for issuance under plan approved by stockholders

1,110,000

3,000,000

Qualitytech, LP

Partners Capital And Distributions [Line Items]

Proceeds net of fees from common equity offering | $

$ 158,663,000

$ 107,495,000

First portion | Performance-Based FFO Units

Partners Capital And Distributions [Line Items]

Vesting period

2 years

Vesting percentage

67.00%

Second portion | Performance-Based FFO Units

Partners Capital And Distributions [Line Items]

Vesting period

3 years

Vesting percentage

33.00%

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, 2019	Dec. 31, 2018	Dec. 31, 2017
Performance-Based Relative TSR Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of units, Granted (in shares)	86,089
Number of units, Cancelled/Expired (in shares)	(1,739)
Ending balance, Number of units (in shares)	84,350
Weighted average fair value, granted, options	$ 54.64
Weighted average fair value, cancelled/expired, options	54.64
Ending balance, weighted average fair value, options	$ 54.64
Performance-Based FFO Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of units, Granted (in shares)	86,089
Number of units, Cancelled/Expired (in shares)	(1,739)
Ending balance, Number of units (in shares)	84,350
Weighted average fair value, granted, options	$ 42.01
Weighted average fair value, cancelled/expired, options	42.01
Ending balance, weighted average fair value, options	$ 42.01
2013 Equity Incentive Plan | Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Beginning balance, Options Outstanding (in shares)	2,037,163	1,369,270	1,058,297
Options, Granted (in shares)	135,594	674,081	468,875
Options, Exercised (in shares)	(125,213)	(6,188)	(155,902)
Options, Cancelled/Expired (in shares)	(112,706)		(2,000)
Ending balance, Options Outstanding (in shares)	1,934,838	2,037,163	1,369,270
Beginning balance, Weighted average exercise price options outstanding	$ 36.86	$ 38.18	$ 31.72
Weighted average exercise price options outstanding, Granted	42.27	34.05	50.66
Weighted average exercise price options outstanding, Exercised	30.80	21.50	31.89
Weighted average exercise price options outstanding, Cancelled/Expired	45.86		37.69
Ending balance, Weighted average exercise price options outstanding	37.11	36.86	38.18
Beginning balance, weighted average fair value, options	7.10	7.80	6.51
Weighted average fair value, granted, options	7.62	5.63	10.32
Weighted average fair value, vested, options	6.21	3.68	6.60
Weighted average fair value, cancelled/expired, options	9.43		8.77
Ending balance, weighted average fair value, options	$ 7.05	$ 7.10	$ 7.80
2013 Equity Incentive Plan | Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Beginning balance, Number of units (in shares)	420,309	381,864	414,691
Number of units, Granted (in shares)	274,564	348,152	228,576
Number of units, Exercised	(279,429)	(224,660)	(163,048)
Number of units, Cancelled/Expired (in shares)	(25,694)	(85,047)	(98,355)
Ending balance, Number of units (in shares)	389,750	420,309	381,864
Beginning balance, Weighted average exercise price units	$ 37.83	$ 46.37	$ 40.67
Weighted average exercise price units, Granted	42.25	35.27	49.86
Weighted average exercise price units, Exercised	39.20	46.23	40.63
Weighted average exercise price units, Cancelled/Expired	42.17	43.50	39.97
Ending balance, Weighted average exercise price units	$ 39.67	$ 37.83	$ 46.37
Class O Units | 2010 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Beginning balance, Number of units (in shares)	102,279	568,040	1,134,811
Number of units, Exercised	(19,969)	(465,761)	(566,771)
Ending balance, Number of units (in shares)	82,310	102,279	568,040
Beginning balance, Weighted average exercise price units	$ 24.05	$ 23.52	$ 24.06
Weighted average exercise price units, Exercised	20.25	23.40	24.60
Ending balance, Weighted average exercise price units	24.97	24.05	23.52
Beginning balance, Weighted average fair value	5.67	5	3.62
Weighted average fair value, Exercised	4.42	4.76	2.24
Ending balance, Weighted average fair value	$ 5.97	$ 5.67	$ 5

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, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value of TSR units granted	54.64
Expected term (years)	5 years 6 months
Expected volatility	28.00%	28.00%	28.00%
Expected dividend yield		4.82%	3.08%
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value of restricted stock granted	$ 42.01	$ 34.03	$ 48.63
Fair value of options granted	$ 7.56	$ 5.55	$ 10.11
Expected term (years)		5 years 6 months	5 years 6 months
Expected dividend yield	3.89%
Expected risk-free interest rates	2.33%	2.69%	2.12%
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value of restricted stock granted	$ 51.25	$ 54.01	$ 51.88
Fair value of options granted	$ 8.28	$ 5.64	$ 10.36
Expected term (years)		6 years	5 years 10 months 24 days
Expected dividend yield	4.19%
Expected risk-free interest rates	2.56%	2.73%	2.18%

Partners' Capital, Equity and_6

Partners' Capital, Equity and Incentive Compensation Plans (Summary of Information About Awards Outstanding) (Details)	12 Months Ended
	Dec. 31, 2019$ / sharesshares
QualityTech LP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards Outstanding	82,310
QTS Realty Trust, Inc.
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards Outstanding	2,493,288
QTS Realty Trust, Inc. | Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards Outstanding	389,750
Remaining term of awards	1 year 8 months 12 days
QTS Realty Trust, Inc. | Performance-Based Relative TSR Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards Outstanding	84,350
Remaining term of awards	2 years
QTS Realty Trust, Inc. | Performance-Based FFO Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards Outstanding	84,350
Remaining term of awards	1 year 4 months 24 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	$ 50.66
Awards Outstanding	1,934,838
Remaining term of awards	3 months 18 days
Class O Units | QualityTech LP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Lower limit of exercise price | $ / shares	$ 20
Upper limit of exercise price | $ / shares	$ 25
Awards Outstanding	82,310

Partners' Capital, Equity and_7

Partners' Capital, Equity and Incentive Compensation Plans (Schedule of Quarterly Cash Dividends) (Details) - USD ($) $ / shares in Units, $ in Thousands

Feb. 18, 2020

Jan. 15, 2020

Jan. 07, 2020

Sep. 30, 2019

Sep. 19, 2019

Jun. 30, 2019

Jun. 25, 2019

Mar. 31, 2019

Mar. 20, 2019

Dec. 31, 2018

Dec. 21, 2018

Oct. 15, 2018

Sep. 30, 2018

Sep. 28, 2018

Sep. 20, 2018

Jun. 29, 2018

Jun. 25, 2018

Jun. 22, 2018

Jun. 20, 2018

Apr. 16, 2018

Apr. 05, 2018

Mar. 22, 2018

Mar. 15, 2018

Dec. 05, 2017

Feb. 28, 2020

Mar. 31, 2019

Dec. 31, 2019

Dec. 31, 2018

Dec. 31, 2017

Dividend rate (as a percent)

7.125%

Preferred stock, shares issued

4,280,000

Preferred stock issuance proceeds, net of costs

$ 407,477

Preferred stock, liquidation preference

$ 25

Net proceeds

$ 268,259

$ 107,549

Series A Redeemable Perpetual Preferred

Dividend rate (as a percent)

7.125%

7.125%

Preferred stock, shares issued

4,280,000

4,280,000

4,280,000

Preferred stock, liquidation preference

$ 25

$ 25

$ 25

Series A Preferred Stock

Record Date

Sep. 30, 2019

Jun. 30, 2019

Mar. 31, 2019

Dec. 31, 2018

Sep. 28, 2018

Jun. 29, 2018

Apr. 5, 2018

Payment Date

Oct. 15, 2019

Jul. 15, 2019

Apr. 15, 2019

Jan. 15, 2019

Oct. 15, 2018

Jul. 16, 2018

Apr. 16, 2018

Per Common Share and Per Unit Rate

$ 0.45

$ 0.45

$ 0.45

$ 0.45

$ 0.45

$ 0.45

$ 0.15

Dividend/Distribution Amount

$ 1,900

$ 1,900

$ 1,900

$ 1,900

$ 1,900

$ 1,900

$ 600

$ 7,600

$ 4,400

Series B Preferred Stock

Record Date

Sep. 30, 2019

Jun. 30, 2019

Mar. 31, 2019

Dec. 31, 2018

Sep. 30, 2018

Payment Date

Oct. 15, 2019

Jul. 15, 2019

Apr. 15, 2019

Jan. 15, 2019

Oct. 15, 2018

Per Common Share and Per Unit Rate

$ 1.63

$ 1.63

$ 1.63

$ 1.63

$ 1.99

Dividend/Distribution Amount

$ 5,100

$ 5,100

$ 5,100

$ 5,100

$ 6,300

$ 20,400

6,300

Series A Redeemable Perpetual Preferred

Preferred stock issuance proceeds, net of costs

$ 103,200

Preferred stock dividends per share cash paid

$ 0.14844

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

25

Share cap price

$ 1.46929

Series B Convertible preferred stock

Dividend rate (as a percent)

6.50%

Preferred stock, shares issued

3,162,500

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 [Member]

Dividend rate (as a percent)

6.50%

Preferred stock, shares issued

3,162,500

Preferred stock issuance proceeds, net of costs

$ 304,000

Number of shares of the company's common stock issued upon initial conversion (in shares)

2.1318

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 dividends per share cash paid

$ 1.9861111

Preferred stock, liquidation preference

$ 100

Period of average daily volume weighted average price

10 days

Share cap price

$ 5.1020

Subsequent Event

Record Date

Mar. 20, 2020

Payment Date

Apr. 7, 2020

Common Stock, Number Of Shares Authorized Under The Program

800,000

Net proceeds

$ 41,600

Subsequent Event | Series A Preferred Stock

Record Date

Mar. 31, 2020

Payment Date

Apr. 15, 2020

Subsequent Event | Series B Preferred Stock

Record Date

Mar. 31, 2020

Payment Date

Apr. 15, 2020

Subsequent Event | Series A Redeemable Perpetual Preferred

Payment Date

Jan. 15, 2020

Per Common Share and Per Unit Rate

$ 0.45

Subsequent Event | Series B Convertible preferred stock [Member]

Payment Date

Jan. 15, 2020

Per Common Share and Per Unit Rate

$ 1.63

Underwriter's Option | Series A Redeemable Perpetual Preferred

Preferred stock, shares issued

280,000

Underwriter's Option | Series B Convertible preferred stock [Member]

Preferred stock, shares issued

412,500

Underwritten Offering | Class A Common Stock

Shares issued

4,000,000

Qualitytech, LP

Preferred stock issuance proceeds, net of costs

$ 407,477

Net proceeds

$ 268,259

$ 107,549

Qualitytech, LP | Series A Redeemable Perpetual Preferred

Dividend rate (as a percent)

7.125%

7.125%

Preferred stock, shares issued

4,280,000

4,280,000

4,280,000

Preferred stock, liquidation preference

$ 25

$ 25

$ 25

Common stock

Record Date

Sep. 19, 2019

Jun. 25, 2019

Mar. 20, 2019

Dec. 21, 2018

Sep. 20, 2018

Jun. 20, 2018

Mar. 22, 2018

Dec. 5, 2017

Payment Date

Oct. 4, 2019

Jul. 9, 2019

Apr. 4, 2019

Jan. 8, 2019

Oct. 4, 2018

Jul. 6, 2018

Apr. 5, 2018

Jan. 5, 2018

Per Common Share and Per Unit Rate

$ 0.44

$ 0.44

$ 0.44

$ 0.41

$ 0.41

$ 0.41

$ 0.41

$ 0.39

Dividend/Distribution Amount

$ 27,300

$ 27,300

$ 27,300

$ 23,700

$ 23,700

$ 23,700

$ 23,700

$ 22,200

$ 105,600

$ 93,300

Shares issued

4,000,000

2,036,000

Common stock | Subsequent Event

Payment Date

Jan. 7, 2020

Per Common Share and Per Unit Rate

$ 0.44

Preferred stock | Series A Preferred Stock

Shares issued

4,280,000

Preferred stock | Series B Preferred Stock

Shares issued

3,163,000

Partners' Capital, Equity and_8

Partners' Capital, Equity and Incentive Compensation Plans (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2019	Dec. 31, 2017	Jun. 30, 2019	Feb. 28, 2019
Partners Capital And Distributions [Line Items]
Proceeds From Issuance Of Common Stock		$ 268,259	$ 107,549
At Market
Partners Capital And Distributions [Line Items]
Maximum value of stock which may be issued		$ 400,000
Class A Common Stock | Underwritten Offering
Partners Capital And Distributions [Line Items]
Shares under underwritten offering					7,762,500
Common stock, par value					$ 0.01
Shares issued	4,000,000
Shares to be issued on a forward basis (in shares)					3,762,500
Class A Common Stock | At Market
Partners Capital And Distributions [Line Items]
Maximum value of stock which may be issued				$ 400,000

Partners' Capital, Equity and_9

Partners' Capital, Equity and Incentive Compensation Plans (Summary of Equity Issued) (Details) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2019USD ($)shares
Subsidiary, Sale of Stock [Line Items]
Remaining Expected Proceeds Available	$ 177,844
February 2019 Class A Offering
Subsidiary, Sale of Stock [Line Items]
Shares Settled | shares	4,000
Proceeds from Issuance or Sale of Equity	$ 159,360
February 2019 Class A Offering March 1, 2020
Subsidiary, Sale of Stock [Line Items]
Forward Shares Sold | shares	3,763
Shares Settled | shares	2,832
Proceeds from Issuance or Sale of Equity	$ 109,998
Remaining Expected Proceeds Available	$ 35,799
At Market
Subsidiary, Sale of Stock [Line Items]
Forward Shares Sold | shares	2,864
Remaining Expected Proceeds Available	$ 142,046
Common Stock Maximum Value Authorized	$ 400,000

Related Party Transactions (Sum

Related Party Transactions (Summary of Related Party Transactions) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Related Party Transaction [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	$ 15,695	$ 36,904	$ 66,723
Affiliated Entity
Related Party Transaction [Line Items]
Lessor, Operating Lease, Term of Contract	10 years
Equity Method Investment Ownership Percentage	50.00%
Tax, utility, insurance and other reimbursement	$ 967	724	796
Rent expense	1,014	1,014	1,014
Capital assets acquired	704	464	561
Total	2,685	$ 2,202	$ 2,371
Development Fees | Affiliated Entity
Related Party Transaction [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	600
Management Fees | Affiliated Entity
Related Party Transaction [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	$ 600

Employee Benefit Plan (Narrativ

Employee Benefit Plan (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plan Disclosure [Line Items]
Employer Contribution on employee benefit plan	$ 2.5	$ 2.5	$ 2.6
First 6% of Employee Contribution [Member]
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 [Member]
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 [Member]
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, 2019	Oct. 13, 2013
Stock conversion ratio	1
Previous Owners Of Quality Tech LP ]Member] | Qualitytech, LP
Quality Tech LP ownership percentage in operating partnership	10.30%	21.20%

Earnings per share of QTS Rea_3

Earnings per share of QTS Realty Trust, Inc. (Computation of Basic and Diluted Net Income per Share) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Earnings per Share [Abstract]
Net income (loss)	$ (3,606)	$ 6,588	$ 7,535	$ 21,148	$ 6,402	$ (6,892)	$ (6,433)	$ (252)	$ 31,665	$ (7,175)	$ 1,457
Loss (Income) attributable to noncontrolling interests									(374)	2,715	(175)
Preferred stock dividends									(28,180)	(16,666)
Earnings attributable to participating securities									(7,828)	(947)	(593)
Net income (loss) available to common stockholders after allocation of participating securities									$ (4,717)	$ (22,073)	$ 689
Weighted average shares outstanding - basic									54,836,801	50,432,590	48,380,964
Effect of Class A partnership units											6,696,000
Effect of Class O units, TSR units and options to purchase Class A common stock on an "as if" converted basis											779,000
Weighted average shares outstanding - diluted									54,836,801	50,432,590	55,855,683
Basic net income (loss) per share	$ (0.20)	$ (0.05)	$ (0.03)	$ 0.20	$ (0.02)	$ (0.25)	$ (0.16)	$ (0.02)	$ (0.09)	$ (0.44)	$ 0.01
Diluted net income (loss) per share	$ (0.20)	$ (0.05)	$ (0.03)	$ 0.20	$ (0.02)	$ (0.25)	$ (0.16)	$ (0.02)	$ (0.09)	$ (0.44)	$ 0.01

Earnings per share of QTS Rea_4

Earnings per share of QTS Realty Trust, Inc. (Antidilutive) (Details) - shares shares in Thousands	12 Months Ended
	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	6,671	6,653
Class O Units
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	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	6,729	3,484

Contracts with Customers (Detai

Contracts with Customers (Details) $ in Thousands	Dec. 31, 2019USD ($)
Contracts with Customers [Abstract]
2020	$ 374,588
2021	323,926
2022	237,556
2023	147,941
2024	103,663
Thereafter	186,871
Total	$ 1,374,545

Fair Value of Financial Instr_2

Fair Value of Financial Instruments (Narrative) (Details) $ in Millions	Dec. 31, 2019USD ($)
Senior Notes. | Fair Value Measurements, Level 2
Fair Value Of Financial Instruments [Line Items]
Fair value of loan based on current market rates	$ 414.5

Quarterly Financial Informati_3

Quarterly Financial Information (Summary of Selected Quarterly Information) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Effect of Fourth Quarter Events [Line Items]
Revenues	$ 123,707	$ 125,255	$ 119,167	$ 112,689	$ 112,337	$ 112,213	$ 112,277	$ 113,697	$ 480,818	$ 450,524	$ 446,510
Operating income (loss)	4,218	13,606	14,598	28,734	12,876	(1,552)	1,882	5,455	61,156	18,661	42,127
Net income (loss)	(3,606)	6,588	7,535	21,148	6,402	(6,892)	(6,433)	(252)	31,665	(7,175)	1,457
Net income (loss) attributable to QTS Realty Trust, Inc.	(2,511)	6,637	7,483	19,558	6,476	(5,282)	(5,431)	(223)	31,291	(4,460)	1,282
Net income (loss) attributable to common stockholders	$ (9,556)	$ (408)	$ 438	$ 12,513	$ (569)	$ (12,327)	$ (7,679)	$ (551)	$ 3,111	$ (21,126)	$ 1,282
Basic (in dollars per share)	$ (0.20)	$ (0.05)	$ (0.03)	$ 0.20	$ (0.02)	$ (0.25)	$ (0.16)	$ (0.02)	$ (0.09)	$ (0.44)	$ 0.01
Diluted (in dollars per share)	$ (0.20)	$ (0.05)	$ (0.03)	$ 0.20	$ (0.02)	$ (0.25)	$ (0.16)	$ (0.02)	$ (0.09)	$ (0.44)	$ 0.01
Qualitytech, LP
Effect of Fourth Quarter Events [Line Items]
Revenues	$ 123,707	$ 125,255	$ 119,167	$ 112,689	$ 112,337	$ 112,213	$ 112,277	$ 113,697	$ 480,818	$ 450,524	$ 446,510
Operating income (loss)	4,218	13,606	14,598	28,734	12,876	(1,552)	1,882	5,455	61,156	18,661	42,127
Net income (loss)	(3,606)	6,588	7,535	21,148	6,402	(6,892)	(6,433)	(252)	31,665	(7,175)	1,457
Net income (loss) attributable to common stockholders	$ (10,651)	$ (457)	$ 490	$ 14,103	$ (643)	$ (13,937)	$ (8,681)	$ (580)	$ 3,485	$ (23,841)	$ 1,457

Subsequent Events (Narrative) (

Subsequent Events (Narrative) (Details) - USD ($) $ / shares in Units, $ in Thousands, shares in Millions

Feb. 18, 2020

Sep. 30, 2019

Jun. 30, 2019

Mar. 31, 2019

Dec. 31, 2018

Sep. 30, 2018

Sep. 28, 2018

Jun. 29, 2018

Apr. 05, 2018

Feb. 28, 2020

Dec. 31, 2019

Dec. 31, 2017

Subsequent Event [Line Items]

Net proceeds

$ 268,259

$ 107,549

Subsequent Event

Subsequent Event [Line Items]

Payable date

Apr. 7, 2020

Record Date

Mar. 20, 2020

Dividends payable, date declared

Feb. 18, 2020

Cash dividend payable per common share

$ 0.47

Number of common shares for sale under ATM Program

0.8

Net proceeds

$ 41,600

Series A Preferred Stock

Subsequent Event [Line Items]

Payable date

Oct. 15, 2019

Jul. 15, 2019

Apr. 15, 2019

Jan. 15, 2019

Oct. 15, 2018

Jul. 16, 2018

Apr. 16, 2018

Record Date

Sep. 30, 2019

Jun. 30, 2019

Mar. 31, 2019

Dec. 31, 2018

Sep. 28, 2018

Jun. 29, 2018

Apr. 5, 2018

Series A Preferred Stock | Subsequent Event

Subsequent Event [Line Items]

Payable date

Apr. 15, 2020

Record Date

Mar. 31, 2020

Dividends payable, date declared

Feb. 18, 2020

Cash dividend payable per common share

$ 0.45

Series B Preferred Stock

Subsequent Event [Line Items]

Payable date

Oct. 15, 2019

Jul. 15, 2019

Apr. 15, 2019

Jan. 15, 2019

Oct. 15, 2018

Record Date

Sep. 30, 2019

Jun. 30, 2019

Mar. 31, 2019

Dec. 31, 2018

Sep. 30, 2018

Series B Preferred Stock | Subsequent Event

Subsequent Event [Line Items]

Payable date

Apr. 15, 2020

Record Date

Mar. 31, 2020

Dividends payable, date declared

Feb. 18, 2020

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, 2019	Dec. 31, 2018	Dec. 31, 2017
Allowance for uncollectible receivables
Balance at beginning of period	$ 3,764	$ 11,453	$ 4,217
Charge to expenses	2,859	(2,275)	7,375
Additions/(deductions)	(4,344)	(5,414)	(139)
Balance at end of period	2,279	3,764	11,453
Valuation allowance for deferred tax assets
Balance at beginning of period	8,361	713	393
Charge to expenses	16,386	7,648	320
Balance at end of period	$ 24,747	$ 8,361	$ 713

Schedule III - Real Estate In_2

Schedule III - Real Estate Investments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Initial costs of land	$ 52,899
Initial costs of buildings and improvements	373,326
Initial costs of construction in progress	270,123
Costs capitalized subsequent to acquisition, Land	77,706
Costs capitalized subsequent to acquisition, Buildings and improvements	1,805,575
Costs capitalized subsequent to acquisition, Construction in progress	650,799
Gross carrying amount, Land	130,605
Gross carrying amount, Buildings and improvements	2,178,901
Gross carrying amount, Construction in progress	920,922
Accumulated depreciation and amortization	(558,560)	$ (467,644)	$ (394,823)	$ (317,834)
Tax Basis of Investments, Cost for Income Tax Purposes	3,410,000
Owned Properties
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Initial costs of land	52,899
Initial costs of buildings and improvements	312,254
Initial costs of construction in progress	270,123
Costs capitalized subsequent to acquisition, Land	77,706
Costs capitalized subsequent to acquisition, Buildings and improvements	1,782,946
Costs capitalized subsequent to acquisition, Construction in progress	650,132
Gross carrying amount, Land	130,605
Gross carrying amount, Buildings and improvements	2,095,200
Gross carrying amount, Construction in progress	920,255
Accumulated depreciation and amortization	(536,167)
Owned Properties | Atlanta, Georgia Campus
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Initial costs of land	12,647
Initial costs of buildings and improvements	35,473
Initial costs of construction in progress	2,209
Costs capitalized subsequent to acquisition, Land	31,941
Costs capitalized subsequent to acquisition, Buildings and improvements	489,827
Costs capitalized subsequent to acquisition, Construction in progress	126,721
Gross carrying amount, Land	44,588
Gross carrying amount, Buildings and improvements	525,300
Gross carrying amount, Construction in progress	128,930
Accumulated depreciation and amortization	$ (190,566)
Date of acquisition	Oct. 3, 2006
Owned Properties | Irving, Texas
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Initial costs of buildings and improvements	$ 5,808
Costs capitalized subsequent to acquisition, Land	8,606
Costs capitalized subsequent to acquisition, Buildings and improvements	363,919
Costs capitalized subsequent to acquisition, Construction in progress	98,170
Gross carrying amount, Land	8,606
Gross carrying amount, Buildings and improvements	369,727
Gross carrying amount, Construction in progress	98,170
Accumulated depreciation and amortization	$ (59,719)
Date of acquisition	Feb. 8, 2013
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	184,484
Costs capitalized subsequent to acquisition, Construction in progress	132,919
Gross carrying amount, Land	2,180
Gross carrying amount, Buildings and improvements	195,684
Gross carrying amount, Construction in progress	139,948
Accumulated depreciation and amortization	$ (74,056)
Date of acquisition	Mar. 20, 2010
Owned Properties | Richmond 01 Virginia
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Date of acquisition	Nov. 15, 2019
Owned Properties | Chicago, Illinois
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Initial costs of construction in progress	$ 17,764
Costs capitalized subsequent to acquisition, Land	9,400
Costs capitalized subsequent to acquisition, Buildings and improvements	205,026
Costs capitalized subsequent to acquisition, Construction in progress	69,114
Gross carrying amount, Land	9,400
Gross carrying amount, Buildings and improvements	205,026
Gross carrying amount, Construction in progress	86,878
Accumulated depreciation and amortization	$ (19,760)
Date of acquisition	Jul. 8, 2014
Owned Properties | Suwanee, Georgia
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Initial costs of land	$ 1,395
Initial costs of buildings and improvements	29,802
Costs capitalized subsequent to acquisition, Land	2,126
Costs capitalized subsequent to acquisition, Buildings and improvements	144,322
Costs capitalized subsequent to acquisition, Construction in progress	5,559
Gross carrying amount, Land	3,521
Gross carrying amount, Buildings and improvements	174,124
Gross carrying amount, Construction in progress	5,559
Accumulated depreciation and amortization	$ (78,510)
Date of acquisition	Sep. 1, 2005
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, Buildings and improvements	23,187
Costs capitalized subsequent to acquisition, Construction in progress	22,156
Gross carrying amount, Land	7,466
Gross carrying amount, Buildings and improvements	103,553
Gross carrying amount, Construction in progress	36,056
Accumulated depreciation and amortization	$ (10,634)
Date of acquisition	Jun. 6, 2016
Owned Properties | Santa Clara, California
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Initial costs of buildings and improvements	$ 15,838
Costs capitalized subsequent to acquisition, Buildings and improvements	98,661
Costs capitalized subsequent to acquisition, Construction in progress	1,238
Gross carrying amount, Buildings and improvements	114,499
Gross carrying amount, Construction in progress	1,238
Accumulated depreciation and amortization	$ (46,536)
Date of acquisition	Nov. 1, 2007
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
Costs capitalized subsequent to acquisition, Buildings and improvements	12,505
Costs capitalized subsequent to acquisition, Construction in progress	163
Gross carrying amount, Land	1,481
Gross carrying amount, Buildings and improvements	65,258
Gross carrying amount, Construction in progress	163
Accumulated depreciation and amortization	$ (13,905)
Date of acquisition	Dec. 21, 2012
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	54,408
Costs capitalized subsequent to acquisition, Construction in progress	(13,262)
Gross carrying amount, Land	9,079
Gross carrying amount, Buildings and improvements	55,018
Gross carrying amount, Construction in progress	35,722
Accumulated depreciation and amortization	$ (3,240)
Date of acquisition	Dec. 16, 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
Costs capitalized subsequent to acquisition, Buildings and improvements	3,066
Costs capitalized subsequent to acquisition, Construction in progress	39
Gross carrying amount, Land	20,700
Gross carrying amount, Buildings and improvements	35,192
Gross carrying amount, Construction in progress	39
Accumulated depreciation and amortization	$ (5,107)
Date of acquisition	Jun. 30, 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
Costs capitalized subsequent to acquisition, Buildings and improvements	19,068
Costs capitalized subsequent to acquisition, Construction in progress	4,688
Gross carrying amount, Land	3,154
Gross carrying amount, Buildings and improvements	48,651
Gross carrying amount, Construction in progress	4,688
Accumulated depreciation and amortization	$ (11,831)
Date of acquisition	Oct. 6, 2017
Owned Properties | Ashburn, Virginia
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Initial costs of construction in progress	$ 75,371
Costs capitalized subsequent to acquisition, Land	16,476
Costs capitalized subsequent to acquisition, Buildings and improvements	156,396
Costs capitalized subsequent to acquisition, Construction in progress	114,004
Gross carrying amount, Land	16,476
Gross carrying amount, Buildings and improvements	156,396
Gross carrying amount, Construction in progress	189,375
Accumulated depreciation and amortization	$ (7,363)
Date of acquisition	Aug. 9, 2017
Owned Properties | Ashburn Virginia 01
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Date of acquisition	Oct. 23, 2017
Owned Properties | Ashburn Virginia 02
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Date of acquisition	Jul. 22, 2019
Owned Properties | Eemshaven, Netherlands
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Initial costs of construction in progress	$ 29,915
Costs capitalized subsequent to acquisition, Construction in progress	7,352
Gross carrying amount, Construction in progress	$ 37,267
Date of acquisition	Apr. 23, 2019
Owned Properties | Phoenix, Arizona
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Initial costs of construction in progress	$ 24,668
Costs capitalized subsequent to acquisition, Buildings and improvements	2,412
Costs capitalized subsequent to acquisition, Construction in progress	7,172
Gross carrying amount, Buildings and improvements	2,412
Gross carrying amount, Construction in progress	31,840
Accumulated depreciation and amortization	$ (1,489)
Date of acquisition	Aug. 11, 2017
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
Costs capitalized subsequent to acquisition, Land	(2)
Costs capitalized subsequent to acquisition, Buildings and improvements	445
Costs capitalized subsequent to acquisition, Construction in progress	3,028
Gross carrying amount, Land	1,741
Gross carrying amount, Buildings and improvements	9,085
Gross carrying amount, Construction in progress	3,028
Accumulated depreciation and amortization	$ (451)
Date of acquisition	Apr. 23, 2019
Owned Properties | Hillsboro, Oregon
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Initial costs of construction in progress	$ 25,657
Costs capitalized subsequent to acquisition, Construction in progress	37,916
Gross carrying amount, Construction in progress	$ 63,573
Date of acquisition	Oct. 3, 2017
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
Costs capitalized subsequent to acquisition, Buildings and improvements	24,486
Costs capitalized subsequent to acquisition, Construction in progress	119
Gross carrying amount, Land	1,777
Gross carrying amount, Buildings and improvements	31,441
Gross carrying amount, Construction in progress	119
Accumulated depreciation and amortization	$ (12,419)
Date of acquisition	Mar. 6, 2008
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
Costs capitalized subsequent to acquisition, Land	36
Costs capitalized subsequent to acquisition, Buildings and improvements	734
Gross carrying amount, Land	436
Gross carrying amount, Buildings and improvements	3,834
Accumulated depreciation and amortization	$ (580)
Date of acquisition	Jun. 3, 2011
Owned Properties | Manassas, Virginia
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Initial costs of construction in progress	$ 24,626
Costs capitalized subsequent to acquisition, Construction in progress	33,036
Gross carrying amount, Construction in progress	57,662
Accumulated depreciation and amortization	(1)
Leased Properties
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Initial costs of buildings and improvements	61,072
Costs capitalized subsequent to acquisition, Buildings and improvements	22,629
Costs capitalized subsequent to acquisition, Construction in progress	667
Gross carrying amount, Buildings and improvements	83,700
Gross carrying amount, Construction in progress	667
Accumulated depreciation and amortization	(22,393)
Leased Properties | Jersey City, New Jersey
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Initial costs of buildings and improvements	1,985
Costs capitalized subsequent to acquisition, Buildings and improvements	28,425
Costs capitalized subsequent to acquisition, Construction in progress	557
Gross carrying amount, Buildings and improvements	30,410
Gross carrying amount, Construction in progress	557
Accumulated depreciation and amortization	$ (13,938)
Date of acquisition	Nov. 1, 2006
Leased Properties | Overland Park, Kansas
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Costs capitalized subsequent to acquisition, Buildings and improvements	$ 888
Costs capitalized subsequent to acquisition, Construction in progress	1
Gross carrying amount, Buildings and improvements	888
Gross carrying amount, Construction in progress	1
Accumulated depreciation and amortization	(658)
Lease Facilities acquired in 2015
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Initial costs of buildings and improvements	59,087
Costs capitalized subsequent to acquisition, Buildings and improvements	(6,684)
Costs capitalized subsequent to acquisition, Construction in progress	109
Gross carrying amount, Buildings and improvements	52,403
Gross carrying amount, Construction in progress	109
Accumulated depreciation and amortization	$ (7,797)
Date of acquisition	Jun. 16, 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, 2019USD ($)
Schedule III - Real Estate Investments [Abstract]
Reduction of costs capitalized	$ 24.9
Reduction of accumulated depreciation	13.5
Tax Basis of Investments, Cost for Income Tax Purposes	$ 3,410

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, 2019	Dec. 31, 2018	Dec. 31, 2017
Property
Balance, beginning of period	$ 2,812,856	$ 2,357,322	$ 1,964,857
Disposals	(41,363)	(43,616)	(18,198)
Additions (acquisitions and improvements)	458,935	499,150	410,663
Balance, end of period	3,230,428	2,812,856	2,357,322
Accumulated depreciation
Balance, beginning of period	(467,644)	(394,823)	(317,834)
Disposals	28,172	30,139	13,970
Additions (depreciation and amortization expense)	(119,088)	(102,960)	(90,959)
Balance, end of period	$ (558,560)	$ (467,644)	$ (394,823)