QualityTech 10-K 25 Feb 19 2018 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2018	Feb. 22, 2019	Jun. 30, 2018
Document Information [Line Items]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	FY
Entity Registrant Name	QTS Realty Trust, Inc.
Entity Central Index Key	1,577,368
Entity Filer Category	Large Accelerated Filer
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Well-known Seasoned Issuer	Yes
Current Fiscal Year End Date	--12-31
Entity Public Float			$ 2
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Class A Common Stock
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		51,021,900
Class B Common Stock
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		128,408
Qualitytech, LP
Document Information [Line Items]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	FY
Entity Registrant Name	QualityTech, LP
Entity Central Index Key	1,561,164
Entity Filer Category	Non-accelerated Filer
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Well-known Seasoned Issuer	No
Current Fiscal Year End Date	--12-31
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Real Estate Assets
Land	$ 105,541	$ 88,216
Buildings, Improvements and Equipment	1,917,251	1,701,287
Less: Accumulated depreciation	(467,644)	(394,823)
Total real estate assets	1,555,148	1,394,680
Construction in progress	790,064	567,819
Real Estate Assets, net	2,345,212	1,962,499
Cash and cash equivalents	11,759	8,243
Rents and other receivables, net	55,093	47,046
Acquired intangibles, net	95,451	109,451
Deferred costs, net	45,096	41,545
Prepaid expenses	6,822	6,163
Goodwill	173,843	173,843
Assets held for sale	71,800
Other assets, net	56,893	66,266
TOTAL ASSETS	2,861,969	2,415,056
LIABILITIES
Unsecured credit facility, net	945,657	825,186
Senior notes, net of debt issuance costs	394,786	394,178
Capital lease, lease financing obligations and mortgage notes payable	4,674	10,565
Accounts payable and accrued liabilities	99,166	113,430
Dividends and distributions payable	29,633	22,222
Advance rents, security deposits and other liabilities	32,679	28,903
Liabilities held for sale	24,349
Deferred income taxes	1,097	4,611
Deferred income	33,241	25,305
TOTAL LIABILITIES	1,565,282	1,424,400
EQUITY
Common stock / units	511	507
Additional paid-in capital	1,062,473	1,049,176
Accumulated other comprehensive income	2,073	1,283
Accumulated dividends in excess of earnings	(278,548)	(173,552)
Total stockholders' equity	1,193,986	877,414
Noncontrolling interests	102,701	113,242
TOTAL EQUITY	1,296,687	990,656
TOTAL LIABILITIES AND EQUITY	2,861,969	2,415,056
Qualitytech, LP
Real Estate Assets
Land	105,541	88,216
Buildings, Improvements and Equipment	1,917,251	1,701,287
Less: Accumulated depreciation	(467,644)	(394,823)
Total real estate assets	1,555,148	1,394,680
Construction in progress	790,064	567,819
Real Estate Assets, net	2,345,212	1,962,499
Cash and cash equivalents	11,759	8,243
Rents and other receivables, net	55,093	47,046
Acquired intangibles, net	95,451	109,451
Deferred costs, net	45,096	41,545
Prepaid expenses	6,822	6,163
Goodwill	173,843	173,843
Assets held for sale	71,800
Other assets, net	56,893	66,266
TOTAL ASSETS	2,861,969	2,415,056
LIABILITIES
Unsecured credit facility, net	945,657	825,186
Senior notes, net of debt issuance costs	394,786	394,178
Capital lease, lease financing obligations and mortgage notes payable	4,674	10,565
Accounts payable and accrued liabilities	99,166	113,430
Dividends and distributions payable	29,633	22,222
Advance rents, security deposits and other liabilities	32,679	28,903
Liabilities held for sale	24,349
Deferred income taxes	1,097	4,611
Deferred income	33,241	25,305
TOTAL LIABILITIES	1,565,282	1,424,400
EQUITY
Accumulated other comprehensive income	2,344	1,449
TOTAL EQUITY	1,296,687	990,656
TOTAL PARTNERS' CAPITAL	1,296,687	990,656
TOTAL LIABILITIES AND EQUITY	2,861,969	2,415,056
Series A Redeemable Perpetual Preferred Units [Member] | Qualitytech, LP
EQUITY
Cumulative redeemable perpetual preferred stock / units	103,212
Series B Convertible Preferred Units [Member] | Qualitytech, LP
EQUITY
Cumulative redeemable perpetual preferred stock / units	304,265
Common units: $0.01 par value, 450,133,000 units authorized, 57,799,035 and 57,245,524 units issued and outstanding as of December 31, 2018 and December 31, 2017, respectively | Qualitytech, LP
EQUITY
Common stock / units	886,866	$ 989,207
Series A Redeemable Perpetual Preferred [Member]
EQUITY
Cumulative redeemable perpetual preferred stock / units	103,212
Series B Convertible Preferred Stock [Member]
EQUITY
Cumulative redeemable perpetual preferred stock / units	$ 304,265

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	450,133,000	450,133,000
Common stock, shares issued	51,123,417	50,701,795
Common stock, shares outstanding	51,123,417	50,701,795
Series A Redeemable Perpetual Preferred [Member]
Dividend rate (as a percent)	7.125%
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, liquidation preference	$ 25	$ 25
Preferred stock, authorized	4,600,000	0
Preferred stock, issued	4,280,000	0
Preferred stock, outstanding	4,280,000	0
Series B Convertible Preferred Stock [Member]
Dividend rate (as a percent)	6.50%
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, liquidation preference	$ 100	$ 100
Preferred stock, authorized	3,162,500	0
Preferred stock, issued	3,162,500	0
Preferred stock, outstanding	3,162,500	0
Series A Redeemable Perpetual Preferred Units [Member] | Qualitytech, LP
Dividend rate (as a percent)	7.125%
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, liquidation preference	$ 25	$ 25
Preferred stock, authorized	4,600,000	0
Preferred stock, issued	4,280,000	0
Preferred stock, outstanding	4,280,000	0
Series B Convertible Preferred Units [Member] | Qualitytech, LP
Dividend rate (as a percent)	6.50%
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, liquidation preference	$ 100	$ 100
Preferred stock, authorized	3,162,500	0
Preferred stock, issued	3,162,500	0
Preferred stock, outstanding	3,162,500	0
Common units: $0.01 par value, 450,133,000 units authorized, 57,799,035 and 57,245,524 units issued and outstanding as of December 31, 2018 and December 31, 2017, respectively | Qualitytech, LP
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	450,133,000	450,133,000
Common stock, shares issued	57,799,035	57,245,524
Common stock, shares outstanding	57,799,035	57,245,524

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenues:
Rental	$ 360,828	$ 335,819	$ 295,723
Total revenues	450,524	446,510	402,363
Operating Expenses:
Property operating costs	148,236	153,209	136,488
Real estate taxes and insurance	12,193	11,959	8,840
Depreciation and amortization	149,891	140,924	124,786
General and administrative	80,857	87,231	83,286
Transaction, integration and impairment costs	2,743	11,060	10,906
Restructuring	37,943
Total operating expenses	431,863	404,383	364,306
Operating income	18,661	42,127	38,057
Other income and expenses:
Interest income	150	67	3
Interest expense	(28,749)	(30,523)	(23,159)
Debt restructuring costs	(605)	(19,992)	(192)
Income (loss) before taxes	(10,543)	(8,321)	14,709
Tax benefit of taxable REIT subsidiaries	3,368	9,778	9,976
Net income (loss)	(7,175)	1,457	24,685
Net (income) loss attributable to noncontrolling interests	2,715	(175)	(3,160)
Net income (loss) attributable to QTS Realty Trust, Inc.	(4,460)	1,282	21,525
Preferred stock dividends	16,666
Net income (loss) attributable to common stockholders	$ (21,126)	$ 1,282	$ 21,525
Net income (loss) per share attributable to common shares:
Basic (in dollars per share)	$ (0.44)	$ 0.01	$ 0.47
Diluted (in dollars per share)	$ (0.44)	$ 0.01	$ 0.46
Weighted Average Number Of Shares Outstanding [Abstract]
Basic (in shares)	50,432,590	48,380,964	46,205,937
Diluted (in shares)	50,432,590	55,855,683	53,962,234
Recoveries From Customers
Revenues:
Revenue	$ 45,386	$ 37,886	$ 29,271
Cloud and managed services
Revenues:
Revenue	35,712	65,466	68,488
Other
Revenues:
Revenue	8,598	7,339	8,881
Qualitytech, LP
Revenues:
Rental	360,828	335,819	295,723
Total revenues	450,524	446,510	402,363
Operating Expenses:
Property operating costs	148,236	153,209	136,488
Real estate taxes and insurance	12,193	11,959	8,840
Depreciation and amortization	149,891	140,924	124,786
General and administrative	80,857	87,231	83,286
Transaction, integration and impairment costs	2,743	11,060	10,906
Restructuring	37,943
Total operating expenses	431,863	404,383	364,306
Operating income	18,661	42,127	38,057
Other income and expenses:
Interest income	150	67	3
Interest expense	(28,749)	(30,523)	(23,159)
Debt restructuring costs	(605)	(19,992)	(192)
Income (loss) before taxes	(10,543)	(8,321)	14,709
Tax benefit of taxable REIT subsidiaries	3,368	9,778	9,976
Net income (loss)	(7,175)	1,457	24,685
Preferred stock dividends	16,666
Net income (loss) attributable to common stockholders	(23,841)	1,457	24,685
Qualitytech, LP | Recoveries From Customers
Revenues:
Revenue	45,386	37,886	29,271
Qualitytech, LP | Cloud and managed services
Revenues:
Revenue	35,712	65,466	68,488
Qualitytech, LP | Other
Revenues:
Revenue	$ 8,598	$ 7,339	$ 8,881

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Net income (loss)	$ (7,175)	$ 1,457	$ 24,685
Other comprehensive income (loss):
Increase in fair value of interest rate swaps	895	1,449
Reclassification of other comprehensive income to interest expense	110	0	0
Comprehensive income (loss)	(6,170)	2,906	24,685
Comprehensive (income) loss attributable to noncontrolling interests	711	(349)	(3,160)
Comprehensive income (loss) attributable to QTS Realty Trust, Inc.	(5,459)	2,557	21,525
Qualitytech, LP
Net income (loss)	(7,175)	1,457	24,685
Other comprehensive income (loss):
Increase in fair value of interest rate swaps	895	1,449
Reclassification of other comprehensive income to interest expense	110
Comprehensive income (loss)	$ (6,170)	$ 2,906	$ 24,685

CONSOLIDATED STATEMENTS OF EQUI

CONSOLIDATED STATEMENTS OF EQUITY - USD ($) $ in Thousands	Series A Redeemable Perpetual Preferred [Member]Qualitytech, LPPreferred stockLimited Partner	Series A Redeemable Perpetual Preferred [Member]Qualitytech, LP	Series A Redeemable Perpetual Preferred [Member]Preferred stock	Series A Redeemable Perpetual Preferred [Member]Total stockholders' Equity	Series A Redeemable Perpetual Preferred [Member]	Series B Convertible preferred stockQualitytech, LPPreferred stockLimited Partner	Series B Convertible preferred stockQualitytech, LP	Series B Convertible preferred stockPreferred stock	Series B Convertible preferred stockTotal stockholders' Equity	Series B Convertible preferred stock	Series A Preferred StockQualitytech, LPCommon stockLimited Partner	Series A Preferred StockQualitytech, LP	Series A Preferred StockAccumulated dividends in excess of earnings	Series A Preferred StockTotal stockholders' Equity	Series A Preferred Stock	Series B Preferred StockQualitytech, LPCommon stockLimited Partner	Series B Preferred StockQualitytech, LP	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 stockGeneral Partner	Qualitytech, LPCommon stockLimited Partner	Qualitytech, LPAccumulated other comprehensive income	Qualitytech, LP	Preferred stock	Common stock	Additional paid-in capital	Accumulated other comprehensive income	Accumulated dividends in excess of earnings	Total stockholders' Equity	Noncontrolling interests	Total
Beginning balance at Dec. 31, 2015																									$ 719,866		$ 412	$ 670,275		$ (52,732)	$ 617,955	$ 101,911	$ 719,866
Limited Partners' Capital,Beginning balance at Dec. 31, 2015																							$ 719,866
Beginning balance, shares at Dec. 31, 2015																											41,226,000
Beginning balance, shares at Dec. 31, 2015																							48,023,000
Beginning balance, shares at Dec. 31, 2015																						1,000
Net share activity through equity award plan																											$ 3	(3)				(1,726)	(1,726)
Net share activity through equity award plan, shares																							280,000				280,000
Issuance of shares through equity award plan																							$ (1,726)		(1,726)
Equity-based compensation expense																							10,584		10,584			9,229			9,229	1,355	10,584
Net proceeds from stock offering																							$ 275,862		275,862		$ 63	252,282			252,345	23,517	275,862
Net proceeds from stock offering (in shares)																							6,325,000				6,325,000
Dividends to stockholders																							$ (66,586)		(66,586)					(66,586)	(66,586)		(66,586)
Distributions to noncontrolling interests																																(9,875)	(9,875)
Partnership distributions																							(9,875)		(9,875)
Net income (loss)																							24,685		24,685					21,525	21,525	3,160	24,685
Ending balance at Dec. 31, 2016																									952,810		$ 478	931,783		(97,793)	834,468	118,342	952,810
Limited Partners' Capital, Ending balance at Dec. 31, 2016																							$ 952,810
Limited Partners' Capital Ending balance, shares at Dec. 31, 2016																							54,628,000
Ending balance, shares at Dec. 31, 2016																						1,000
Ending balance, shares at Dec. 31, 2016																											47,831,000
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
Reclassification of noncontrolling interest upon conversion of partnership units to common stock																											$ 3	8,352			8,355	(8,355)
Reclassification of noncontrolling interest upon conversion of partnership units to common stock, shares																											253,000
Increase in fair value of interest rate swaps																								$ 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
Net proceeds from stock offering																							$ 107,495		107,495		$ 20	95,952			95,972	11,523	107,495
Net proceeds from stock offering (in shares)																							2,036,000				2,036,000
Dividends to stockholders																							$ (77,041)		(77,041)					(77,041)	(77,041)		(77,041)
Distributions 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
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
Partners' Capital, Ending Balance at Dec. 31, 2017																									990,656
Ending balance, shares at Dec. 31, 2017																											50,702,000
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 in fair value of interest rate swaps																								895	895				790		790	105	895
Equity-based compensation expense																							$ 18,100		18,100			16,014			16,014	2,086	18,100
Net proceeds from stock offering	$ 103,212	$ 103,212	$ 103,212	$ 103,212	$ 103,212	$ 304,265	$ 304,265	$ 304,265	$ 304,265	$ 304,265
Net proceeds from stock offering (in shares)	4,280,000		4,280,000			3,163,000		3,163,000
Dividends on Preferred Units											$ (6,046)	$ (6,046)	$ (6,046)	$ (6,046)	$ (6,046)	$ (10,621)	$ (10,621)	$ (10,621)	$ (10,621)	$ (10,621)
Dividends to stockholders																							(83,869)		(83,869)					(83,869)	(83,869)		(83,869)
Distributions 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
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
Ending balance, shares at Dec. 31, 2018																										7,443,000	51,123,000

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOW $ in Thousands	12 Months Ended
	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)
Cash flow from operating activities:
Net income (loss)	$ (7,175)	$ 1,457	$ 24,685
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization	143,354	136,585	120,805
Above/Below Market Lease Amortization	465	865	659
Amortization of deferred loan costs	3,856	3,640	3,285
Amortization of senior notes discount		229	261
Loss on extinguishment of debt		19,912
Equity-based compensation expense	14,972	13,863	10,584
Bad debt expense (recoveries)	(2,275)	3,519	1,752
Write off of deferred loan costs	605	80	224
Deferred tax benefit	(2,970)	(10,742)	(10,171)
Loss on sale of property	6,994
Integration, impairment & restructuring costs	19,575	9,027	1,927
Changes in operating assets and liabilities
Rents and other receivables, net	(6,495)	(12,881)	(17,101)
Prepaid expenses	(3,063)	755	158
Other assets	4,518	282	(561)
Accounts payable and accrued liabilities	8,573	(5,071)	6,290
Advance rents, security deposits and other liabilities	2,069	5,491	5,959
Deferred income	8,270	3,312	5,038
Net cash provided by operating activities	191,273	170,323	153,794
Cash flow from investing activities:
Proceeds from sale of property	2,779
Acquisitions, net of cash acquired	(117,029)	(127,038)	(173,067)
Additions to property and equipment	(484,303)	(307,314)	(279,905)
Net cash used in investing activities	(598,553)	(434,352)	(452,972)
Cash flow from financing activities:
Credit facility proceeds	483,000	888,000	574,000
Credit facility repayments	(362,000)	(696,000)	(459,002)
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	(3,964)	(10,862)	(4,177)
Payment of Preferred Stock dividend	(10,728)
Payment of common stock dividends	(82,579)	(74,592)	(62,585)
Distribution to noncontrolling interests	(10,759)	(10,289)	(9,619)
Proceeds from exercise of stock options	246	4,972	858
Payment of tax withholdings related to equity based awards	(2,205)	(4,725)	(2,584)
Principal payments on capital lease obligations	(7,626)	(12,224)	(12,600)
Dulles, VA Vault Capital Lease Repayment		(17,785)
Mortgage principal debt repayments	(66)	(54)
Preferred stock issuance proceeds, net of costs	407,477
Common stock issuance proceeds, net of costs		107,549	275,663
Net cash provided by financing activities	410,796	262,692	299,954
Net increase (decrease) in cash and cash equivalents	3,516	(1,337)	776
Cash and cash equivalents, beginning of period	8,243	9,580	8,804
Cash and cash equivalents, end of period	11,759	8,243	9,580
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION
Cash paid for interest (excluding deferred financing costs and amounts capitalized)	24,532	29,934	19,897
Noncash investing and financing activities:
Accrued capital additions	76,890	75,965	40,431
Accrued preferred stock dividends	5,939
Accrued deferred financing costs	76	458	39
Accrued equity issuance costs	115	25
Acquisitions, net of cash acquired:
Land		9,363	7,602
Buildings, improvements and equipment	445	14,341	80,975
Construction in Progress	114,283	103,334	62,884
Rents and other receivables, net			(2,042)
Acquired intangibles	2,301		34,521
Deferred costs			4,414
Prepaid expenses			574
Goodwill			(7,895)
Other assets			309
Accounts payable and accrued liabilities			(922)
Advance rents, security deposits and other liabilities			(1,343)
Deferred income			35
Deferred income taxes			6,045
Total acquisitions, net of cash acquired	117,029	127,038	173,067
Qualitytech, LP
Cash flow from operating activities:
Net income (loss)	(7,175)	1,457	24,685
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization	143,354	136,585	120,805
Above/Below Market Lease Amortization	465	865	659
Amortization of deferred loan costs	3,856	3,640	3,285
Amortization of senior notes discount		229	261
Loss on extinguishment of debt		19,912
Equity-based compensation expense	14,972	13,863	10,584
Bad debt expense (recoveries)	(2,275)	3,519	1,752
Write off of deferred loan costs	605	80	224
Deferred tax benefit	(2,970)	(10,742)	(10,171)
Loss on sale of property	6,994
Integration, impairment & restructuring costs	19,575	9,027	1,927
Changes in operating assets and liabilities
Rents and other receivables, net	(6,495)	(12,881)	(17,101)
Prepaid expenses	(3,063)	755	158
Other assets	4,518	282	(561)
Accounts payable and accrued liabilities	8,573	(5,071)	6,290
Advance rents, security deposits and other liabilities	2,069	5,491	5,959
Deferred income	8,270	3,312	5,038
Net cash provided by operating activities	191,273	170,323	153,794
Cash flow from investing activities:
Proceeds from sale of property	2,779
Acquisitions, net of cash acquired	(117,029)	(127,038)	(173,067)
Additions to property and equipment	(484,303)	(307,314)	(279,905)
Net cash used in investing activities	(598,553)	(434,352)	(452,972)
Cash flow from financing activities:
Credit facility proceeds	483,000	888,000	574,000
Credit facility repayments	(362,000)	(696,000)	(459,002)
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	(3,964)	(10,862)	(4,177)
Payment of Preferred Stock dividend	(10,728)
Payment of cash dividends	(82,579)	(74,592)	(62,585)
Proceeds from exercise of stock options	246	4,972	858
Payment of tax withholdings related to equity based awards	(2,205)	(4,725)	(2,584)
Principal payments on capital lease obligations	(7,626)	(12,224)	(12,600)
Dulles, VA Vault Capital Lease Repayment		(17,785)
Mortgage principal debt repayments	(66)	(54)
Preferred stock issuance proceeds, net of costs	407,477
Common stock issuance proceeds, net of costs		107,549	275,663
Partnership distributions	(10,759)	(10,289)	(9,619)
Net cash provided by financing activities	410,796	262,692	299,954
Net increase (decrease) in cash and cash equivalents	3,516	(1,337)	776
Cash and cash equivalents, beginning of period	8,243	9,580	8,804
Cash and cash equivalents, end of period	11,759	8,243	9,580
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION
Cash paid for interest (excluding deferred financing costs and amounts capitalized)	24,532	29,934	19,897
Noncash investing and financing activities:
Accrued capital additions	76,890	75,965	40,431
Accrued preferred stock dividends	5,939
Accrued deferred financing costs	76	458	39
Accrued equity issuance costs	115	25
Acquisitions, net of cash acquired:
Land		9,363	7,602
Buildings, improvements and equipment	445	14,341	80,975
Construction in Progress	114,283	103,334	62,884
Rents and other receivables, net			(2,042)
Acquired intangibles	2,301		34,521
Deferred costs			4,414
Prepaid expenses			574
Goodwill			(7,895)
Other assets			309
Accounts payable and accrued liabilities			(922)
Advance rents, security deposits and other liabilities			(1,343)
Deferred income			35
Deferred income taxes			6,045
Total acquisitions, net of cash acquired	$ 117,029	$ 127,038	$ 173,067

Description of Business

Description of Business	12 Months Ended
	Dec. 31, 2018
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 their subsidiaries, the “Company”) and the subsidiaries of the Operating Partnership, is engaged in the business of owning, acquiring, constructing, redeveloping and managing multi-tenant data centers. The Company’s portfolio consists of 25 wholly-owned and leased properties with data centers located throughout the United States, Canada, Europe and Asia. 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, 2018, QTS owned approximately 88.5% 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, 2018
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 810, Consolidation , and the Company is the primary beneficiary of the VIE. As discussed below, the Company’s only material asset is its ownership interest in the Operating Partnership, and consequently, all of its assets and liabilities represent those assets and liabilities of the Operating Partnership. The Company’s debt is an obligation of the Operating Partnership where the creditors may have recourse, under certain circumstances, against the credit of the Company. QTS is the sole general partner of the Operating Partnership, and its only material asset consists of its ownership interest in the Operating Partnership. Management operates QTS and the Operating Partnership as one business. The management of QTS consists of the same employees as the management of the Operating Partnership. QTS does not conduct business itself, other than acting as the sole general partner of the Operating Partnership and issuing public equity from time to time. QTS has not issued or guaranteed any indebtedness. Except for net proceeds from public equity issuances by QTS, which are contributed to the Operating Partnership in exchange for units of limited partnership interest of the Operating Partnership, the Operating Partnership generates all remaining capital required by the business through its operations, the direct or indirect incurrence of indebtedness, and the issuance of partnership units. Therefore, as general partner with control of the Operating Partnership, QTS consolidates the Operating Partnership for financial reporting purposes. 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 4.75% Senior Notes due 2025 and the unsecured credit facility, both discussed in Note 6, are fully, unconditionally, and jointly and severally guaranteed by 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 Operating Partnership, QTS Finance Corporation (the co-issuer of the 4.75% Senior Notes due 2025) or any subsidiary guarantor. The indenture governing the 4.75% 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 subsidiaries. This includes the operating results of the Operating Partnership for all periods presented. Use of Estimates – The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. Significant items subject to such estimates and assumptions include the useful lives of fixed assets, allowances for doubtful accounts and deferred tax assets and the valuation of derivatives, real estate assets, acquired intangible assets and certain accruals. Principles of Consolidation – The consolidated financial statements of QTS Realty Trust, Inc. include the accounts of QTS Realty Trust, Inc. and its controlled subsidiaries. The consolidated financial statements of QualityTech, LP include the accounts of QualityTech, LP and its subsidiaries. All significant intercompany accounts and transactions have been eliminated in the financial statements. Real Estate Assets – Real estate assets are reported at cost. All capital improvements for the income-producing properties that extend their useful lives are capitalized to individual property improvements and depreciated over their estimated useful lives. Depreciation for real estate assets is generally provided on a straight-line basis over 40 years from the date the property was placed in service. Property improvements are depreciated on a straight-line basis over the life of the respective improvement ranging from 20 to 40 years from the date the components were placed in service. Leasehold improvements are depreciated over the lesser of 20 years or through the end of the respective life of the lease. Repairs and maintenance costs are expensed as incurred. For the year ended December 31, 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. For the year ended December 31, 2016, depreciation expense related to real estate assets and non-real estate assets was $77.5 million and $13.1 million, respectively, for a total of $90.6 million. The Company capitalizes certain 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 costs) begins when development efforts commence and ends when the asset is ready for its intended use. Capitalization of such costs, excluding interest, aggregated to $17. 4 million, $12.7 million and $11.0 million for the years ended December 31, 2018, 2017 and 2016 respectively. Interest is capitalized during the period of development by applying the Company’s 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 $26.8 million, $14.3 million and $11.4 million for the years ended December 31, 2018, 2017 and 2016, respectively. Acquisitions and Sales – Acquisitions of real estate and other entities are either accounted for as asset acquisitions or business combinations depending on facts and circumstances. When substantially all of the fair value of gross assets acquired is concentrated in a single identifiable asset or a group of similar identifiable assets, the transaction is accounted for as an asset acquisition. In an asset acquisition, the purchase price paid for assets acquired is allocated between identified tangible and intangible assets acquired based on relative fair value. Transaction costs associated with asset acquisitions are capitalized. When substantially all of the fair value of assets acquired is not concentrated in a group of similar identifiable assets, the set of assets will generally be considered a business. When accounting for business combinations purchase accounting is applied to the assets and liabilities related to all real estate investments acquired in accordance with the accounting requirements of ASC 805, Business Combinations , which requires the recording of net assets of acquired businesses at fair value. The fair value of the consideration transferred is assigned to the acquired tangible assets, consisting primarily of land, construction in progress, building and improvements, and identified intangible assets and liabilities, consisting of the value of above-market and below-market leases, value of in-place leases, value of customer relationships, trade names, software intangibles and capital leases. The excess of the fair value of liabilities assumed, common stock issued and cash paid over the fair value of identifiable assets acquired is allocated to goodwill, which is not amortized by the Company. Transaction costs associated with business combinations are expensed as incurred. In developing estimates of fair value of acquired assets and assumed liabilities, management analyzed 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. This amortization expense is accounted for as real estate amortization expense. Acquired customer relationships are amortized as amortization expense on a straight-line basis over the expected life of the customer relationship. This amortization expense is 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 the Company is a lessor as well as a reduction to or increase in rent expense over the remaining lease terms in the case of the Company as 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. The Company accounts for the sale of assets under Financial Accounting Standards Board (“FASB”) Accounting Standards Update (“ASU”) No. 2017-05, Other Income—Gains and Losses from the Derecognition of Nonfinancial Assets (Subtopic 610-20), which provides for recognition or derecognition based on transfer of ownership. During the year ended December 31, 2018, the Company recognized a $7.0 million net loss on sale of equipment associated with the Company’s strategic growth plan. The loss on disposal is included within the “Restructuring” line item of the consolidated statements of operations. Impairment of Long-Lived Assets, Intangible Assets and Goodwill – The Company reviews its long-lived assets and intangible assets for impairment when events or changes in circumstances indicate that the carrying amount of the assets may not be recoverable. Recoverability of assets to be held and used is measured by comparison of the carrying amount to the future net cash flows, undiscounted and without interest, expected to be generated by the asset group. If the net carrying value of the asset exceeds the value of the undiscounted cash flows, the fair value of the asset is assessed and may be considered impaired. An impairment loss is recognized based on the excess of the carrying amount of the impaired asset over its fair value. For the year ended December 31, 2018, the Company recognized $8.8 million of impairment losses related to certain product-related assets, which is included in the “Restructuring” line item of the consolidated statement of operations. For the year ended December 31, 2017, the Company recognized a $1.6 million impairment related to equipment used to support its cloud and managed service platform, which is included in the “Transaction, integration and impairment costs” line item of the consolidated statement of operations. No impairment losses were recorded for the year ended December 31, 2016. 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 the Company performed as of October 1, 2018, the Company determined qualitatively that it is not more likely than not that the fair value of the Company’s one reporting unit was less than the carrying amount, thus it did not perform a quantitative analysis. As the Company continues to operate and assess its goodwill at the consolidated level and its market capitalization significantly exceeds its net asset value, further analysis was not deemed necessary as of December 31, 2018. Assets Held for Sale – As of December 31, 2018, the Company believed it was probable that it would complete a sale of the Manassas facility to a joint venture within one year and accordingly reclassified certain assets, as well as liabilities associated with those assets, as held for sale. The asset value of $71.8 million associated with the held for sale assets is included within the “Assets held for sale” line item of the consolidated statements of financial position and primarily consists of construction in progress. The liability value of $24.3 million associated with the held for sale liabilities is included within the “Liabilities held for sale” line item of the consolidated statements of financial position and primarily consists of accounts payable and accrued liabilities associated with construction in progress assets. See Note 19 for further discussion of the joint venture. Cash and Cash Equivalents – The Company considers all demand deposits and money market accounts purchased with a maturity date of three months or less at the date of purchase to be cash equivalents. The Company’s account balances at one or more institutions periodically exceed the Federal Deposit Insurance Corporation (“FDIC”) insurance coverage and, as a result, there is concentration of credit risk related to amounts on deposit in excess of FDIC coverage. The Company mitigates this risk by depositing a majority of its funds with several major financial institutions. The Company also has not experienced any losses and does not believe that the risk is significant. Deferred Costs – Deferred costs, net, on the Company’s 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 sheet, were $3.9 million, $3.6 million and $3.3 million for the years ended December 31, 2018, 2017 and 2016, respectively. During the year ended December 31, 2018, the Company wrote off unamortized financing costs of $0.6 million to the income statement in connection with the modification of its unsecured credit facility in November 2018 whereby the company 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, the Company wrote off unamortized financing costs of $5.2 million to the income statement primarily in connection with the replacement of its $300 million 5.875% senior notes with the $400 million of 4.75% notes. During the year ended December 31, 2016, the Company wrote off unamortized financing costs of $0.2 million to the income statement in connection with the modification of its unsecured credit facility in December 2016 whereby the company increased the total capacity and extended the term for an additional year. Deferred financing costs presented as assets on the balance sheet related to revolving debt arrangements, net of accumulated amortization are as follows: December 31, December 31, (dollars in thousands) 2018 2017 Deferred financing costs $ 11,530 $ 9,775 Accumulated amortization (3,859) (1,908) Deferred financing costs, net $ 7,671 $ 7,867 Deferred financing costs presented as offsets to the associated liabilities on the balance sheets related to fixed term debt arrangements, net of accumulated amortization, are as follows: December 31, December 31, (dollars in thousands) 2018 2017 Deferred financing costs $ 14,501 $ 12,675 Accumulated amortization (2,944) (1,039) Deferred financing costs, net $ 11,557 $ 11,636 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. These costs are incurred when the Company executes lease agreements and represent only incremental costs that would not have been incurred if the lease agreement had not been executed. The Company incurs the same incremental costs to obtain managed services and cloud contracts with customers that are accounted for pursuant to ASC 606, Revenue from Contracts with Customers . These costs are accounted for under ASC 340-40, Other Assets and Deferred Costs , which includes a similar framework for capitalization that is applied to the Company’s leasing contracts as only the direct and incremental costs of obtaining a revenue contract are capitalized. Because the framework of accounting for these costs and the underlying nature of the costs are the same for the Company’s revenue and lease contracts, the costs are presented on a combined basis within the Company’s financial statements and within the below table. Both revenue and leasing commissions are capitalized and generally amortized over the term of the related leases or the expected term of the contract using the straight-line method. If a customer lease terminates prior to the expiration of its initial term, any unamortized initial direct costs related to the lease are written off to amortization expense. Amortization of deferred leasing costs totaled $21.3 million, $18.5 million and $15.2 million for the years ended December 31, 2018, 2017 and 2016, respectively. Deferred leasing costs, net of accumulated amortization are as follows: December 31, December 31, (dollars in thousands) 2018 2017 Deferred leasing costs $ 63,018 $ 54,868 Accumulated amortization (25,593) (20,956) Deferred leasing costs, net $ 37,425 $ 33,912 Revenue Recognition – In May 2014, the Financial Accounting Standards Board (“FASB”) issued guidance codified in Accounting Standards Codification (“ASC”) Topic 606, Revenue from Contracts with Customers , which supersedes the prior revenue recognition requirements in ASC Topic 605, Revenue Recognition . Under this new guidance, entities should recognize revenues to depict the transfer of promised goods or services to customers in an amount that reflects the consideration the entity expects to receive in exchange for those goods or services. This standard also requires enhanced disclosures. The standard is effective for annual and interim periods beginning after December 15, 2017. Retrospective and modified retrospective application is allowed. The Company adopted ASC Topic 606 effective January 1, 2018, and elected the modified retrospective transition approach. The adoption did not result in a cumulative catch-up adjustment to opening equity and does not change the recognition pattern of the Company’s operating revenues, a significant portion of which are recognized as rental income in accordance with ASC 840, Leases . Under ASC 606, disclosures are required to provide information on the nature, amount, timing, and uncertainty of revenue, certain costs, and cash flows arising from contracts with customers. The Company derives its revenues from leases with customers for data center space which include lease rental revenue components and nonlease revenue components, such as power, cloud and managed services. A description of each of the Company’s disaggregated revenue streams as presented on the face of the consolidated statements of operations is as follows: Rental Revenue The Company’s 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. The Company does 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 the Company to provide a series of distinct services of standing ready to deliver the power over the contracted term which is co-terminus with the lease. The Company recognizes revenue from these nonlease fixed power components over time on a straight-line basis in the same manner as the lease components of the contract as the customer simultaneously receives and consumes the power benefits provided over the lease term. Rental revenue also includes amortization of set-up fees which are amortized over the term of the respective lease as discussed below. Recoveries from Customers Certain customer leases contain provisions under which customers reimburse the Company 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 are nonlease components and relate specifically to the Company’s variable power arrangements, whereby customers pay variable monthly fees for the specific amount of power utilized at the current utility rates. The Company’s 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. the Company provides power to its customers) and customers utilize the power. Reimbursement of real estate taxes, insurance, common area maintenance, or other operating expenses are accounted for as executory costs under lease guidance and are recognized as revenue in the period that the associated expenses are recognized. Cloud and Managed Services The Company, through its TRS, may provide both its cloud product and use of its managed services to its customers on an individual or combined basis. In both its 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 the Company accounts for the services as a series of distinct services. Service fee revenue is recognized as the revenue is earned, which generally coincides with the services being provided. As the Company has 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, the Company recognizes monthly revenue for the amount invoiced. With respect to the transaction price allocated to remaining performance obligations within the Company’s cloud and managed service contracts, the Company has elected to use the optional exemption provided by the standard whereby the Company is not required to estimate the total transaction price allocated to remaining performance obligations as the Company applies 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. Other Other revenue primarily consists of 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 $29.7 million and $23.4 million as of December 31, 2018 and December 31, 2017, respectively. Advance Rents and Security Deposits – Advance rents, typically prepayment of the following month’s rent, consist of payments received from customers prior to the time they are earned and are recognized as revenue in subsequent periods when earned. Security deposits are collected from customers at the lease origination and are generally refunded to customers upon lease expiration. Deferred Income – Deferred income generally results from non-refundable charges paid by the customer at lease inception to prepare their space for occupancy. The Company records this initial payment, commonly referred to as set-up fees, as a deferred income liability which amortizes into rental revenue over the term of the related lease on a straight-line basis. Deferred income was $33.2 million, $25.3 million and $22.0 million as of December 31, 2018, 2017 and 2016, respectively. Additionally, $12.5 million, $10.7 million and $9.4 million of deferred income was amortized into revenue for the years ended December 31, 2018, 2017 and 2016, respectively. Equity-based Compensation – Equity-based compensation costs are measured based upon their estimated fair value on the date of grant or modification and amortized ratably over their respective service periods. We have elected to account for forfeitures as they occur. Equity-based compensation expense net of forfeited and repurchased awards was $15.0 million, $13.9 million and $10.6 million for the years ended December 31, 2018, 2017 and 2016, respectively. Equity-based compensation expense for the year ended December 31, 2018 excludes $3.1 million of equity-based compensation expense associated with the acceleration of equity awards related to certain employees impacted by the Company’s strategic growth plan. The aforementioned equity-based compensation expense is included in the “Restructuring” expense line item on the consolidated statements of operations. Allowance for Uncollectible Accounts Receivable – Rents receivable are recognized when due and are carried at cost, less an allowance for doubtful accounts. The Company records a provision for losses on rents receivable equal to the estimated uncollectible accounts, which is based on management’s historical experience and a review of the current status of the Company’s receivables. As necessary, the Company also establishes an appropriate allowance for doubtful accounts for receivables arising from the straight-lining of rents. The aggregate allowance for doubtful accounts was $3.8 million and $11.5 million as of December 31, 2018 and December 31, 2017, respectively. Capital Leases and Lease Financing Obligations – The Company evaluates leased real estate to determine whether the lease should be classified as a capital or operating lease in accordance with U.S. GAAP. The Company periodically enters into capital leases for certain data center equipment as well as fiber optic transmission cabling. In addition, through its acquisition of Carpathia Hosting, Inc. (“Carpathia”) on June 16, 2015, the Company is party to capital leases for property and equipment, as well as certain financing obligations. The outstanding liabilities for the capital leases were $2.7 million and $7.8 million as of December 31, 2018 and 2017, respectively. The outstanding liabilities for the lease financing obligations were $0.1 million and $0.9 million as of December 31, 2018 and 2017, respectively. The net book value of the assets associated with these leases was approximately $1.8 million and $14.7 million as of December 31, 2018 and 2017, respectively. Depreciation related to the associated assets is included in depreciation and amortization expense in the Statements of Operations. See Note 6 for further discussion of capital leases and lease financing obligations. Segment Information – The Company manages its business as one operating segment and thus one reportable segment consisting of a portfolio of investments in data centers located primarily in the United States. Customer Concentrations – As of December 31, 2018, one of the Company’s customers represented 12.8% of its total monthly rental revenue. No other customers exceeded 5% of total monthly rental revenue. As of December 31, 2018, two of the Company’s cu

Acquisitions

Acquisitions	12 Months Ended
	Dec. 31, 2018
Acquisitions [Abstract]
Acquisitions	3. Acquisitions (All references to square footage, acres and megawatts are unaudited) Land Acquisitions During 2018, the Company completed multiple acquisitions of land in Manassas, Virginia totaling 118 acres for approximately $37.0 million. A portion of the land is currently being used to support the construction of a data center. These acquisitions were accounted for as asset acquisitions. The land acquired in the Manassas purchases, as well as subsequent costs for construction in progress, are included within the “Construction in Progress” line item of the consolidated balance sheets. Total construction in progress costs related the Manassas facility were $116.2 million as of December 31, 2018, of which $71.0 million were included within the “Assets held for sale” line item of the consolidated balance sheets as the Company contributed the Manassas facility to a 50% owned joint venture subsequent to December 31, 2018. In October 2018, the Company completed the acquisition of approximately 55 acres of land in Atlanta, Georgia for approximately $80.1 million adjacent to its existing Atlanta-Metro mega data center. The land acquired contained existing buildings as well as a below market ground lease asset with the Company as lessee for a portion of the land. The total purchase price allocation recorded on the opening balance sheet is included within the following line items of the consolidated balance sheet as of December 31, 2018: $0.4 million in “Buildings, improvement and equipment”, $2.3 million in “Acquired Intangibles, net” and $77.4 million in “Construction in Progress.” The acquisition was accounted for as an asset acquisition. The Company completed multiple land acquisitions during the year ended December 31, 2017. In July 2017, the Company completed the acquisition of approximately 84 acres of land in Phoenix, Arizona for approximately $25 million to be used for future development. In August 2017, the Company completed the acquisition of approximately 24 acres of land in Ashburn, Virginia for approximately $17 million. In October 2017, the Company completed the acquisition of approximately 28 acres of land in Ashburn, Virginia for approximately $36 million to be used for future development. In October 2017, the Company completed the acquisition of approximately 92 acres of land in Hillsboro, Oregon for approximately $26 million to be used for future development. The fair value of the land acquired in each of the four aforementioned acquisitions, as well as costs associated with the subsequent development of the data center in Ashburn, aggregated $163.6 million as of December 31, 2017 and was included within the “Construction in Progress” line item of the consolidated balance sheets. Fort Worth Acquisition On December 16, 2016, the Company completed the acquisition of the Fort Worth facility for approximately $50.1 million. This facility is located in Fort Worth, Texas, and consists of 53 acres and approximately 262,000 gross square feet. This facility has a basis of design of 80,000 square feet and contains approximately 50 MW of available utility power. This acquisition was funded with a draw on the unsecured revolving credit facility. The Company accounted for this acquisition in accordance with ASC 805, Business Combinations, as a business combination. The Company valued the assets acquired and liabilities assumed primarily using Level 3 inputs. In December 2017, the Company finalized the Fort Worth purchase price allocation. The following table summarizes the consideration for the Fort Worth facility and the final allocation of the fair value of assets acquired and liabilities assumed at the acquisition date (in thousands): Final Fort Worth Allocation as of Preliminary Allocation Reported as of December 31, 2016 Adjustments to Fair Value Land $ 136 $ 136 $ — Buildings and improvements 610 610 — Construction in progress 48,987 48,984 3 Acquired intangibles 237 240 (3) Deferred costs 23 23 — Other assets 7 7 — Net Working Capital 86 86 — Total identifiable assets acquired $ 50,086 $ 50,086 $ — Acquired intangibles are amortized as both amortization expense as well as offsets to rental revenue. Piscataway Acquisition On June 6, 2016, the Company completed the acquisition of the Piscataway facility. This facility is located in the New York metro area on 38 acres and consists of 360,000 gross square feet, including approximately 89,000 square feet of raised floor, and approximately 18 MW of critical power. The Piscataway facility supports future growth with space for an additional approximately 87,000 square feet of raised floor in the existing structure, as well as capacity for over 8 MW of additional critical power. This acquisition was funded with a draw on the unsecured revolving credit facility. The Company accounted for this acquisition in accordance with ASC 805, Business Combinations, as a business combination. The Company generally valued the assets acquired and liabilities assumed using Level 3 inputs. In June 2017, the Company finalized the Piscataway purchase price allocation. The following table summarizes the consideration for the Piscataway facility and the final allocation of the fair value of assets acquired and liabilities assumed at the acquisition date (in thousands): Final Piscataway Allocation as of Preliminary Allocation Reported as of June 30, 2016 Adjustments to Fair Value Land $ 7,466 $ 7,440 $ 26 Buildings and improvements 80,366 78,370 1,996 Construction in progress 13,900 13,900 — Acquired intangibles 19,581 21,668 (2,087) Deferred costs 4,390 4,084 306 Other assets 106 106 — Total identifiable assets acquired 125,809 125,568 241 Acquired below market lease 809 568 241 Net working capital 2,019 2,019 — Total liabilities assumed 2,828 2,587 241 Net identifiable assets acquired $ 122,981 $ 122,981 $ — There were no measurement period adjustments recorded during the 2017 reporting period associated with the Piscataway purchase price allocation. Vault Asset Acquisition On October 6, 2017, the Company completed the buyout of its Vault facility in Dulles, Virginia. The facility consists of approximately 87,000 gross square feet, including approximately 31,000 square feet of raised floor, and approximately 13 MW of available utility power. The Company previously leased the property under a capital lease agreement of approximately $17.8 million and purchased it for approximately $34.1 million cash, for a net purchase price of $16.3 million. This acquisition was funded with a draw on the unsecured revolving credit facility. The Company accounted for this acquisition in accordance with ASC Topic 840, Leases.

Acquired Intangibles Assets and

Acquired Intangibles Assets and Liabilities	12 Months Ended
	Dec. 31, 2018
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, 2018 December 31, 2017 Useful Lives Gross Accumulated Net Carrying Gross Accumulated Net Carrying Customer Relationships 12 years $ 95,705 $ (28,461) $ 67,244 $ 95,705 $ (20,512) $ 75,193 In-Place Leases 0.5 to 10 years 32,066 (17,670) 14,396 32,066 (12,987) 19,079 Solar Power Agreement (1) 17 years 13,747 (3,639) 10,108 13,747 (2,830) 10,917 Platform Intangible 3 years 9,600 (9,600) — 9,600 (8,133) 1,467 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 4,649 (3,247) 1,402 4,649 (2,328) 2,321 Tradenames 3 years 3,100 (3,100) — 3,100 (2,626) 474 Total Intangible Assets $ 161,168 $ (65,717) $ 95,451 $ 158,867 $ (49,416) $ 109,451 Solar Power Agreement (1) 17 years 13,747 (3,639) 10,108 13,747 (2,830) 10,917 Acquired Unfavorable Leases Acquired below market leases - as Lessor 3 to 4 years 809 (611) 198 809 (375) 434 Acquired above market leases - as Lessee 11 to 12 years 2,453 (767) 1,686 2,453 (550) 1,903 Total Intangible Liabilities (2) $ 17,009 $ (5,017) $ 11,992 $ 17,009 $ (3,755) $ 13,254 (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 statement 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 $0.5 million, $0.9 million, and $0.7 million for the years ended December 31, 2018, 2017 and 2016, respectively. The estimated amortization of acquired favorable and unfavorable leases for each of the five succeeding fiscal years ending December 31 is as follows (in thousands): Net Rental Revenue Net Rental Expense Increase / (Decrease) 2019 $ 479 $ (166) 2020 647 (166) 2021 46 (166) 2022 17 (166) 2023 17 (166) Thereafter — 1,446 Total $ 1,205 $ 615 Net amortization of all other identified intangible assets and liabilities was $15.0 million, $18.2 million and $19.0 million for the years ended December 31, 2018, 2017 and 2016, 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): 2019 $ 11,965 2020 11,379 2021 10,137 2022 9,910 2023 9,910 Thereafter 28,339 Total $ 81,640

Real Estate Assets and Construc

Real Estate Assets and Construction in Progress	12 Months Ended
	Dec. 31, 2018
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 properties owned or leased by the Company as of December 31, 2018 and 2017 (in thousands): As of December 31, 2018: Property Location Land Buildings and Improvements Construction Total Cost Atlanta, Georgia (Atlanta-Metro) $ 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 (1) 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 (1) (5) — — 45,194 45,194 Santa Clara, California (2) — 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 (3) — 43,347 9,334 52,681 Hillsboro, Oregon (1) — — 39,835 39,835 Phoenix, Arizona (1) — — 29,562 29,562 Other (4) 2,213 35,720 113 38,046 $ 105,541 $ 1,917,251 $ 790,064 $ 2,812,856 (1) 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. (2) Owned facility subject to long-term ground sublease. (3) Includes 10 facilities. All facilities are leased, including those subject to capital leases. (4) Consists of Miami, FL; Lenexa, KS; and Overland Park, KS facilities. (5) Excludes $71.0 million of construction in progress included within the “Assets held for sale” line item of the consolidated balance sheets. As of December 31, 2017: Property Location Land Buildings and Construction Total Cost Atlanta, Georgia (Atlanta-Metro) $ 20,416 $ 452,836 $ 28,614 $ 501,866 Irving, Texas 8,606 276,894 86,320 371,820 Richmond, Virginia 2,180 254,603 61,888 318,671 Chicago, Illinois 9,400 81,463 135,479 226,342 Suwanee, Georgia (Atlanta-Suwanee) 3,521 165,915 3,620 173,056 Piscataway, New Jersey 7,466 83,251 37,807 128,524 Santa Clara, California (1) — 100,028 6,989 107,017 Ashburn, Virginia (2) — — 106,952 106,952 Dulles, Virginia 3,154 76,239 3,565 82,958 Sacramento, California 1,481 64,251 58 65,790 Leased Facilities (3) — 59,460 5,534 64,994 Fort Worth, Texas 9,079 17,894 33,774 60,747 Princeton, New Jersey 20,700 32,948 451 54,099 Hillsboro, Oregon (2) — — 29,278 29,278 Phoenix, Arizona (2) — — 27,402 27,402 Other (4) 2,213 35,505 88 37,806 $ 88,216 $ 1,701,287 $ 567,819 $ 2,357,322 (1) Owned facility subject to long-term ground sublease. (2) Represent land purchases. Land acquisition costs, as well as subsequent development costs, are included within construction in progress until development on the land has ended and the asset is ready for its intended use. (3) Includes 11 facilities. All facilities are leased, including those subject to capital leases. (4) Consists of Miami, FL; Lenexa, KS; Overland Park, KS; and Duluth, GA facilities. (5)

Debt

Debt	12 Months Ended
	Dec. 31, 2018
Debt [Abstract]
Debt	6. Debt Below is a listing of the Company’s outstanding debt, including capital leases and lease financing obligations, as of December 31, 2018 and 2017 (in thousands): Weighted Average Coupon Interest Rate at Maturities as of December 31, December 31, December 31, 2018 (1) December 31, 2018 2018 2017 Unsecured Credit Facility Revolving Credit Facility December 17, 2022 $ 252,000 $ 131,000 Term Loan I December 17, 2023 350,000 350,000 Term Loan II April 27, 2024 350,000 350,000 Senior Notes November 15, 2025 400,000 400,000 Lenexa Mortgage May 1, 2022 1,801 1,866 Capital Lease and Lease Financing Obligations 2019 - 2038 2,873 8,699 1,356,674 1,241,565 Less net debt issuance costs (11,557) (11,636) Total outstanding debt, net $ 1,345,117 $ 1,229,929 (1) The coupon interest rates associated with Term Loan I and Term Loan II incorporate the effects of the Company’s interest rate swaps in effect as of December 31, 2018. Credit Facilities, Senior Notes and Mortgage Notes Payable (a) Unsecured Credit Facility – In November 2018, the Company executed an amendment to its amended and restated unsecured credit facility (the unsecured credit facility”), which among other things included extending the term, modifying or eliminating certain covenants and reduced pricing by 20 basis points. The unsecured credit facility includes a $350 million term loan which matures on December 17, 2023, a $350 million term loan which matures on April 27, 2024, and an $820 million revolving credit facility which matures on December 17, 2022, with a one year extension option. Amounts outstanding under the amended unsecured credit facility bear interest at a variable rate equal to, at the Company’s election, LIBOR or a base rate, plus a spread that will vary depending upon the Company’s leverage ratio. For revolving credit loans, the spread ranges from 1.35% to 1.95% for LIBOR loans and 0.35% to 0.95% for base rate loans. For term loans, the spread ranges from 1.30% to 1.90% for LIBOR loans and 0.30% to 0.90% for base rate loans. The unsecured credit facility also provides for borrowing capacity of up to $200 million in various foreign currencies, and a $500 million accordion feature, subject to obtaining additional loan commitments. Under the unsecured credit facility, the capacity may be increased from the current capacity of $1.52 billion to $2.02 billion subject to certain conditions set forth in the credit agreement, including the consent of the administrative agent and obtaining necessary commitments. The Company is also required to pay a commitment fee to the lenders assessed on the unused portion of the unsecured revolving credit facility. At the Company’s election, it 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 amended unsecured credit facility is subject to ongoing compliance with a number of customary affirmative and negative covenants. As of December 31, 2018, the Company was in compliance with all of its covenants. As of December 31, 2018, the Company had outstanding $952.0 million of indebtedness under the unsecured credit facility, consisting of $252.0 million of outstanding borrowings under the unsecured revolving credit facility and $700.0 million outstanding under the term loans, exclusive of net debt issuance costs of $6.3 million. In connection with the unsecured credit facility, as of December 31, 2018, the Company had letters of credit outstanding aggregating to $4.1 million. As of December 31, 2018, the weighted average interest rate for amounts outstanding under the unsecured credit facility, including the effects of interest rate swaps, was 3.53%. The Company has also entered into certain interest rate swap agreements. See Note 7 – ‘Interest Rate Swaps’ for additional details. (b) Senior Notes – On November 8, 2017, the Operating Partnership and QTS Finance Corporation, a subsidiary of the Operating Partnership formed solely for the purpose of facilitating the offering of the 5.875% Senior Notes due 2022 (collectively, the “Issuers”), the Company and certain of its other subsidiaries entered into a purchase agreement pursuant to which the Issuers issued $400 million aggregate principal amount of 4.75% Senior Notes due November 15, 2025 (the “Senior Notes”) in a private offering. The Senior Notes have an interest rate of 4.750% per annum and were issued at a price equal to 100% of their face value. The net proceeds from the offering were used to fund the redemption of, and satisfy and discharge the indenture pursuant to which the Issuers issued, all of their outstanding 5.875% Senior Notes and to repay a portion of the amount outstanding under the Company’s unsecured revolving credit facility. As of December 31, 2018, the outstanding net debt issuance costs associated with the Senior Notes were $5.2 million. 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, 2018 per the contractual maturities and excluding extension options, capital leases and lease financing obligations, are as follows (in thousands): 2019 $ 62 2020 71 2021 74 2022 253,594 2023 350,000 Thereafter 750,000 Total $ 1,353,801 As of December 31, 2018, the Company was in compliance with all of its covenants. Capital Leases The Company has historically entered into capital leases for certain data center equipment as well as fiber optic transmission cabling. In addition, through its acquisition of Carpathia on June 16, 2015, the Company acquired capital leases of both equipment and certain properties. Total outstanding liabilities for capital leases were $2.7 million as of December 31, 2018, of which $0.3 million were assumed through the Carpathia acquisition, all of which was related to the lease of real property. Carpathia had entered into capital lease arrangements for datacenter space under two lease agreements that expired in 2018 and 2019 at its Harrisonburg, Virginia and Ashburn, Virginia locations. Total recurring monthly payments range from approximately $0.2 million to $0.5 million during the terms of the leases, in addition to payments made for utilities. Depreciation related to the associated assets for the capital leases is included in depreciation and amortization expense in the Statements of Operations. The following table summarizes the Company’s combined future payment obligations, excluding interest, as of December 31, 2018, on capital leases and lease financing obligations (in thousands): 2019 $ 994 2020 151 2021 48 2022 44 2023 49 Thereafter 1,587 Total $ 2,873

Interest Rate Swaps

Interest Rate Swaps	12 Months Ended
	Dec. 31, 2018
Interest Rate Derivative Instruments [Abstract]
Interest Rate Swaps	7. Interest Rate Swaps The Company’s 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, the Company primarily uses interest rate swaps as part of its 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 the Company making fixed-rate payments over the life of the agreements without exchange of the underlying notional amount. On April 5, 2017, the Company 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 each term loan, from January 2, 2018 through December 17, 2021 and April 27, 2022, respectively, at approximately 3.3% assuming the current LIBOR spread of 1.3%. On December 20, 2018, the Company 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 each term loan, from December 17, 2021 and April 27, 2022 through the current maturity dates of the respective term loans which are December 17, 2023 and April 27, 2024, respectively. The weighted average effective fixed interest rate on the $400 million notional amount of term loan financing following the execution of these swap agreements will approximate 3.9%, commencing on December 17, 2021 and April 27, 2022, assuming the current LIBOR spread of 1.3%. Additionally, the Company entered into forward interest rate swap agreements with an aggregate notional amount of $200 million. The forward swap agreements effectively fix the interest rate on $200 million of additional term loan borrowings, $100 million of swaps allocated to each term loan, from January 2, 2020 through the current maturity dates of December 17, 2023 and April 27, 2024, respectively. The Company reflects its 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 “Advance rents, security deposits and other liabilities” line items, as applicable. As of December 31, 2018, the fair value of interest rates swaps included an asset of $5.3 million as well as a liability of $3.0 million. As of December 31, 2017, the fair value of interest rate swaps was an asset of $1.4 million. The forward interest rate swap agreements are derivatives that currently qualify for hedge accounting whereby the Company records 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 $0.1 million for the year ended December 31, 2018. No amounts were reclassified from other comprehensive income to interest expense on the consolidated statements of operations for the years ended December 31, 2017 and 2016. There was no ineffectiveness recognized for the years ended December 31, 2018, 2017 and 2016. During the subsequent twelve months, beginning January 1, 2019, we estimate that $2.1 million will be reclassified from other comprehensive income as a reduction to interest expense. Interest rate derivatives and their fair values as of December 31, 2018 and December 31, 2017 were as follows (in thousands): Fixed One Month Notional Amount LIBOR rate per Fair Value (1) December 31, 2018 December 31, 2017 annum Effective Date Expiration Date December 31, 2018 December 31, 2017 $ 25,000 $ 25,000 January 2, 2018 December 17, 2021 $ 331 $ 100 100,000 100,000 January 2, 2018 December 17, 2021 1,318 401 75,000 75,000 January 2, 2018 December 17, 2021 990 298 50,000 50,000 January 2, 2018 April 27, 2022 667 158 100,000 100,000 January 2, 2018 April 27, 2022 1,341 337 50,000 50,000 January 2, 2018 April 27, 2022 666 155 100,000 — January 2, 2020 December 17, 2023 (782) — 100,000 — January 2, 2020 April 27, 2024 (818) — 200,000 — December 17, 2021 December 17, 2023 (722) — 200,000 — April 27, 2022 April 27, 2024 (648) — $ 1,000,000 $ 400,000 $ 2,343 $ 1,449 (1) Balance recorded in “other assets, net” in the consolidated balance sheets if in an asset position and recorded in “Advance rents, security deposits and other liabilities” in the consolidated balance sheets if in a liability position. (2) (3)

Restructuring

Restructuring	12 Months Ended
	Dec. 31, 2018
Restructuring [Abstract]
Restructuring	8. Restructuring On February 20, 2018, the Company announced a strategic growth plan to realign its product offerings around its hyperscale and hybrid colocation product offerings, along with technology and services from the Company’s cloud and managed services business that support hyperscale and hybrid colocation customers. As part of the strategic growth plan, the Company narrowed its focus around certain of its cloud and managed services offerings and on April 24, 2018, the Company entered into definitive agreements with General Datatech, L.P. (“GDT”), an international provider of managed IT solutions, pursuant to which the Company agreed to assign to GDT certain assets, contracts and liabilities associated with the Company’s cloud and managed services products. These assets primarily consist of customer contracts and certain physical equipment. As of December 31, 2018, the Company had successfully completed the migration of the associated customers and transitioned impacted assets, contracts and liabilities to GDT. In connection with the definitive agreements, the Company and GDT also agreed to an ongoing relationship where the Company will lease data center space to GDT as well as provide ongoing services to GDT to support the transitioned customers. Expenses associated with the strategic growth plan are included in the “Restructuring” line item on the consolidated statements of operations. The Company does not expect to incur restructuring expenses related to the strategic growth plan during the year ended December 31, 2019. Restructuring expenses incurred during year ended December 31, 2018 are as follows (in thousands): Equity-Based Compensation and Product-Related Severance Professional Fees and Other Total Restructuring expense $ 6,910 (1) $ 7,740 (2) $ 23,293 (3) $ 37,943 (1) As of December 31, 2018, the outstanding liability for accrued but unpaid severance expense was $0.4 million, which is included in the “Accounts payable and accrued liabilities” line item of the consolidated balance sheets. (2) As of December 31, 2018, there was no outstanding liability for accrued but unpaid equity based compensation and professional fees expense. (3) Product-related and other expenses primarily relate to impairment write-downs of depreciated property as well as losses incurred on the sale of equipment. As of December 31, 2018, the outstanding liability for accrued but unpaid product related and other expense was $2.3 million, which is included in the “Accounts payable and accrued liabilities” line item of the consolidated balance sheets. (4)

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2018
Commitments and Contingencies [Abstract]
Commitments and Contingencies	9. 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, 2018
Partners' Capital, Equity and Incentive Compensation Plans [Abstract]
Partners' Capital, Equity and Incentive Compensation Plans	10. 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, 2018, the Operating Partnership had four classes of limited partnership units outstanding: Series A Preferred Stock Units, Series B Convertible Preferred Stock 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 are now redeemable 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 following full vesting (if such unit is subject to vesting) 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 the Company’s 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. In May 2015, the total number of shares available for issuance under the 2013 Equity Incentive Plan was increased to 4,750,000. 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, 2018, 2017 and 2016: 2010 Equity Incentive Plan 2013 Equity Incentive Plan Weighted Weighted Weighted Weighted Weighted average Weighted average average Number of average Average fair Number of Grant date average fair Restricted Grant date Class O units exercise price value Class RS units value Options exercise price value Stock value Outstanding at January 1, 2016 1,292,899 $ 23.76 $ 3.68 39,875 $ 22.18 867,882 $ 27.80 $ 5.56 394,908 $ 33.82 Granted — — — — — 229,693 45.78 9.91 237,563 45.53 Exercised/Vested (1) (158,088) 21.56 4.18 — — (29,543) 25.70 4.96 (122,136) 33.26 Released from restriction — — — (39,875) 22.18 — — — — — Cancelled/Expired (2) — — — — — (9,735) 32.14 6.95 (95,644) 33.92 Outstanding at December 31, 2016 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 (1) This represents 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. This also represents Class O units which were converted to Class A units and options to purchase Class A common stock which were exercised for their respective columns. (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, 2018, 2017 and 2016 are included in the following table on a per share basis. Options to purchase shares of Class A common stock were valued using the Black-Scholes model. 2018 2017 2016 Fair value of restricted stock granted $34.03 - $54.01 $48.63 - $51.88 $45.78 - $56.28 Fair value of options granted $5.55 - $5.64 $10.11 - $10.36 $9.57 - $9.97 Expected term (years) 5.5 - 6.0 5.5 - 5.9 5.5 - 5.9 Expected volatility 30.7% - 31.3% Expected dividend yield Expected risk-free interest rates 2.69% - 2.73% 2.12% - 2.18% 1.42% - 1.48% The following tables summarize information about awards outstanding as of December 31, 2018. Operating Partnership Awards Outstanding Weighted average Awards remaining Exercise prices outstanding vesting period (years) Class O Units $ 20.00 - 25.00 102,279 — Total Operating Partnership awards outstanding 102,279 QTS Realty Trust, Inc. Awards Outstanding Weighted average Awards remaining Exercise prices outstanding vesting period (years) Restricted stock $ — 420,309 1.7 Options to purchase Class A common stock $ 21.00 - 50.66 2,037,163 1.3 Total QTS Realty Trust, Inc. awards outstanding 2,457,472 Any remaining nonvested awards are valued as of the grant date and generally vest ratably over a defined service period. As of December 31, 2018 there were approximately 0.4 million and 0. 8 million nonvested restricted Class A common stock and options to purchase Class A common stock outstanding, respectively. As of December 31, 2018 the Company had $13.7 million of unrecognized equity-based compensation expense which will be recognized over a remaining weighted-average vesting period of 1.4 years. The total intrinsic value of the awards outstanding at December 31, 2018 was $25.5 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, 2018 and 2017: Year Ended December 31, 2018 Aggregate Per Share and Dividend/Distribution Record Date Payment Date Per Unit Rate Amount (in millions) Common Stock 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 $ 1.62 $ 93.3 Series A Preferred Stock 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 $ 1.04 $ 4.4 Series B Preferred Stock September 30, 2018 October 15, 2018 $ 1.99 $ 6.3 $ 6.3 Year Ended December 31, 2017 Aggregate Per Share and Dividend/Distribution Record Date Payment Date Per Unit Rate Amount (in millions) Common Stock September 22, 2017 October 5, 2017 $ 0.39 $ 22.2 June 16, 2017 July 6, 2017 0.39 21.6 March 16, 2017 April 5, 2017 0.39 21.4 December 16, 2016 January 5, 2017 0.36 19.7 $ 1.53 $ 84.9 Additionally, subsequent to December 31, 2018, the Company paid the following dividends: · On January 8, 2019, the Company paid its regular quarterly cash dividend of $0.41 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 21, 2018. · On January 15, 2019, 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, 2018. · On January 15, 2019, the Company paid a cash dividend for the period of October 15, 2018 through January 14, 2019 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, 2018. Equity Issuances In March 2017, the Company established an “at-the-market” equity offering program (the “ATM Program”) pursuant to which the Company may issue, from time to time, up to $300 million of its Class A common stock. The Company issued no shares under the ATM Program during the year ended December 31, 2018. 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: • • 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 initial conversion rate is 2.1264 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 will not be 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: • • QTS Realty Trust, Inc. Employee Stock Purchase Plan In June 2015, the Company 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 the Company’s 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. The Company reserved 250,000 shares of its 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, the stockholders of the Company approved an amendment and restatement of the 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 the Company’s Class A common stock at a discount of up to 10% (as determined by the Compensation Committee). Employees of the Company and its majority-owned subsidiaries who have been employed for at least thirty days and who perform at least thirty hours of service per week for the 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 stocks, owns shares representing five percent or more of the total combined voting power or value of all classes of shares of the 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.

Related Party Transactions

Related Party Transactions	12 Months Ended
	Dec. 31, 2018
Related Party Transactions [Abstract]
Related Party Transactions	11. Related Party Transactions The Company periodically executes transactions with entities affiliated with its 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 the Company’s officers and directors. The transactions which occurred during the years ended December 31, 2018, 2017 and 2016 are outlined below (in thousands): December 31, (dollars in thousands) 2018 2017 2016 Tax, utility, insurance and other reimbursement $ 724 $ 796 $ 878 Rent expense 1,014 1,014 1,014 Capital assets acquired 464 561 323 Total $ 2,202 $ 2,371 $ 2,215

Employee Benefit Plan

Employee Benefit Plan	12 Months Ended
	Dec. 31, 2018
Employee Benefit Plan [Abstract]
Employee Benefit Plan	12. 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 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, $2.6 million and $2.5 million to the 401(k) Plan for the years ended December 31, 2018, 2017 and 2016, respectively.

Noncontrolling Interest

Noncontrolling Interest	12 Months Ended
	Dec. 31, 2018
Noncontrolling Interest [Abstract]
Noncontrolling Interest	13. 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 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, 2018, the noncontrolling ownership interest percentage of QualityTech, LP was 11.5%.

Earnings per share of QTS Realt

Earnings per share of QTS Realty Trust, Inc.	12 Months Ended
	Dec. 31, 2018
Earnings per Share [Abstract]
Earnings per Share	14. 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 contain non-forfeitable rights to dividends and thus are participating securities and are included in the computation of 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 were included in the calculation of earnings per share using the two-class method for all periods presented. The computation of basic and diluted net income per share is as follows (in thousands, except per share data): Year Ended December 31, 2018 2017 2016 Numerator: Net income (loss) $ (7,175) $ 1,457 $ 24,685 Loss (income) attributable to noncontrolling interests 2,715 (175) (3,160) Preferred stock dividends (16,666) — — Earnings attributable to participating securities Net income (loss) available to common stockholders after allocation of participating securities $ (22,073) $ 689 $ 24,685 Denominator: Weighted average shares outstanding - basic 50,433 Effect of Class A partnership units — Effect of Class O units and options to purchase Class A common stock on an "as if" converted basis — Weighted average shares outstanding - diluted 50,433 Basic net income (loss) per share $ (0.44) $ 0.01 $ 0.47 Diluted net income (loss) per share $ (0.44) $ 0.01 $ 0.46 * Note: The table above does not include Class A partnership units of 6.7 million for the year ended December 31, 2018, 0.4 million reflecting the effects of Class O units and options to purchase common stock on an "as if" converted basis for the year ended December 31, 2018, and 3.5 million reflecting the effects of Series B Convertible preferred stock on an “as if” converted basis for the year ended December 31, 2018, as their respective inclusion would have been antidilutive. *

Operating Leases, as Lessee

Operating Leases, as Lessee	12 Months Ended
	Dec. 31, 2018
Leases [Abstract]
Operating Leases, as Lessee	15. Operating Leases, as Lessee The Company leases and/or licenses several data center facilities and related equipment, its corporate headquarters and additional office space. Many of the data center facilities that the Company leases were acquired in 2015 through its acquisition of Carpathia. In addition, the Company has entered into a long-term ground sublease for its Santa Clara property through October 2052. Rent expense for the aforementioned leases was $15.4 million, $17.9 million and $20.1 million for the years ended December 31, 2018, 2017 and 2016, respectively, and is classified in property operating costs and general and administrative expenses in the accompanying Statements of Operations. The Company recorded $0.1 million of capitalized rent for the year ended December 31, 2016. The Company recorded no capitalized rent for the years ended December 31, 2018 and 2017. The future non-cancellable minimum rental payments required under operating leases and/or licenses at December 31, 2018 are as follows (in thousands): Year Ending December 31, 2019 $ 14,778 2020 11,128 2021 11,008 2022 10,161 2023 10,250 Thereafter 57,221 Total $ 114,546

Contracts with Customers

Contracts with Customers	12 Months Ended
	Dec. 31, 2018
Contracts with Customers [Abstract]
Contracts with Customers	16. Contracts with Customers Future minimum payments to be received under non-cancelable customer contracts (inclusive of payments for contracts which have not yet commenced, and exclusive of recoveries of operating costs from customers) are as follows for the years ending December 31 (in thousands): Year Ending December 31, 2019 $ 355,440 2020 291,162 2021 232,905 2022 152,069 2023 84,368 Thereafter 112,889 Total $ 1,228,833

Fair Value of Financial Instrum

Fair Value of Financial Instruments	12 Months Ended
	Dec. 31, 2018
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 the Company could realize on disposition of the financial instruments. The use of different market assumptions and/or estimation methodologies may have a material effect on estimated fair value amounts. Short-term instruments: The carrying amounts of cash and cash equivalents and restricted cash approximate fair value. Interest rate swaps: Currently, the Company uses interest rate swaps to manage its 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, the Company incorporates credit valuation adjustments to appropriately reflect both its own nonperformance risk and the respective counterparty’s nonperformance risk in the fair value measurements. In adjusting the fair value of its derivative contracts for the effect of nonperformance risk, the Company has considered the impact of netting and any applicable credit enhancements, such as collateral postings, thresholds, mutual puts, and guarantees. Although the Company has determined that the majority of the inputs used to value its derivatives fall within Level 2 of the fair value hierarchy, the credit valuation adjustments associated with its derivatives utilize Level 3 inputs, such as estimates of current credit spreads to evaluate the likelihood of default by the Company and its counterparties. However, as of December 31, 2018, the Company assessed the significance of the impact of the credit valuation adjustments on the overall valuation of its derivative positions and has determined that the credit valuation adjustments are not significant to the overall valuation of its derivatives. As a result, the Company has determined that its derivative valuations in their entirety are classified in Level 2 of the fair value hierarchy. The Company does not have any fair value measurements on a recurring basis using significant unobservable inputs (Level 3) as of December 31, 2018 or December 31, 2017. Credit facility and Senior Notes: The Company’s unsecured credit facility did not have interest rates which were materially different than current market conditions and therefore, the fair value approximated the carrying value. The fair value of the Company’s Senior Notes was estimated using Level 2 “significant other observable inputs,” primarily based on quoted market prices for the same or similar issuances. At December 31, 2018, the fair value of the Senior Notes was approximately $374.0 million. Other debt instruments: The fair value of the Company’s other debt instruments (including capital leases, lease financing obligations 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, 2018
Quarterly Financial Information [Abstract]
Quarterly Financial Information	17. Quarterly Financial Information (unaudited) The tables below reflect the selected quarterly information for the years ended December 31, 2018 and 2017 for QTS (in thousands except share data): Three Months Ended December 31, September 30, June 30, March 31, 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) 2017 Revenues $ 118,911 $ 113,767 $ 107,868 $ 105,964 Operating income 7,553 12,833 10,826 10,915 Net income (loss) (16,113) 7,394 4,608 5,568 Net income (loss) attributable to QTS Realty Trust, Inc. (14,142) 6,507 4,040 4,877 Net income (loss) attributable to common stockholders (14,142) 6,507 4,040 4,877 Net income (loss) per share attributable to common shares - basic (0.29) 0.13 0.08 0.10 Net income (loss) per share attributable to common shares - diluted (0.29) 0.13 0.08 0.10 The table below reflects the selected quarterly information for the years ended December 31, 2018 and 2017 for the Operating Partnership (in thousands): Three Months Ended December 31, September 30, June 30, March 31, 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) 2017 Revenues $ 118,911 $ 113,767 $ 107,868 $ 105,964 Operating income 7,553 12,833 10,826 10,915 Net income (16,113) 7,394 4,608 5,568 Net income (loss) attributable to common unitholders (16,113) 7,394 4,608 5,568

Subsequent Events

Subsequent Events	12 Months Ended
	Dec. 31, 2018
Subsequent Events [Abstract]
Subsequent Events	19. Subsequent Events On February 22, 2019, QTS completed the formation of a joint venture with Alinda Capital Partners (“Alinda”), a premier infrastructure investment firm. QTS contributed a 118,000 square foot hyperscale data center in Manassas, VA to the venture in exchange for an equity interest in the joint venture. As this joint venture will be managed by a premier board of directors initially consisting of equal representation from QTS and Alinda, we expect the joint venture to be accounted for as an equity method investment. As of December 31, 2018, the Company classified certain assets, as well as liabilities associated with those assets, as held for sale pursuant to the contribution of those assets and liabilities to the joint venture. The asset value of $71.8 million associated with the held for sale assets is included within the “Assets held for sale” line item of the consolidated balance sheets and primarily consists of construction in progress. The liability value of $24.3 million associated with the held for sale liabilities is included within the “Liabilities held for sale” line item of the consolidated balance sheet and primarily consists of accounts payable and accrued liabilities associated with construction in progress assets. In January 2019, the Company paid its regular quarterly cash dividends on its common stock, Series A Preferred Stock and Series B Preferred Stock. See the ‘Liquidity and Capital Resources’ section of Item 7 for additional details. Subsequent to December 31, 2018, the Company authorized the following dividends: · On February 22, 2019, the Company announced that its board of directors authorized payment of a regular quarterly cash dividend of $0.44 per common share and per unit in the Operating Partnership, payable on April 4, 2019, to stockholders and unit holders of record as of the close of business on March 20, 2019. · On February 22, 2019, 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, 2019, to holders of Series A Preferred Stock of record as of the close of business on March 31, 2019. · On February 22, 2019, 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, 2019, to holders of Series B Preferred Stock of record as of the close of business on March 31, 2019.

Schedule II - Valuation and Qua

Schedule II - Valuation and Qualifying Accounts	12 Months Ended
	Dec. 31, 2018
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, 2018 Balance at Balance at Year Ended December 31, beginning of Charge to Additions/ end of (dollars in thousands) period expenses (Deductions) period Allowance for doubtful accounts 2018 $ 11,453 $ (2,275) $ (5,414) $ 3,764 2017 4,217 7,375 (139) 11,453 2016 5,063 1,752 (2,598) 4,217 Valuation allowance for deferred tax assets 2018 $ 713 $ 7,648 $ — $ 8,361 2017 393 320 — 713 2016 393 — — 393

Schedule III - Real Estate Inve

Schedule III - Real Estate Investments	12 Months Ended
	Dec. 31, 2018
Schedule III - Real Estate Investments [Abstract]
Schedule III - Real Estate Investments	QTS REALTY TRUST, INC. QUALITYTECH, LP SCHEDULE III – REAL ESTATE INVESTMENTS December 31, 2018 Initial Costs Costs Capitalized Subsequent to Acquisition Gross Carrying Amount As of December 31, 2018 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 (Atlanta-Metro) $ 12,647 $ 35,473 $ — $ 7,769 $ 457,973 $ 88,253 $ 20,416 $ 493,446 $ 88,253 $ (162,808) 10/3/2006 Irving, Texas — 5,808 — 8,606 339,807 99,445 8,606 345,615 99,445 (40,650) 2/8/2013 Richmond, Virginia 2,000 11,200 — 180 241,898 67,932 2,180 253,098 67,932 (60,731) 3/20/2010 Chicago, Illinois — — 17,764 9,400 130,150 115,331 9,400 130,150 133,095 (10,302) 7/8/2014 Suwanee, Georgia (Atlanta-Suwanee) 1,395 29,802 — 2,126 136,496 3,188 3,521 166,298 3,188 (66,678) 9/1/2005 Piscataway, New Jersey 7,466 80,366 13,900 — 17,440 19,572 7,466 97,806 33,472 (6,585) 6/6/2016 Santa Clara, California — 15,838 — — 82,710 7,600 — 98,548 7,600 (40,466) 11/1/2007 Sacramento, California 1,481 52,753 — — 12,121 92 1,481 64,874 92 (11,522) 12/21/2012 Fort Worth, Texas 136 610 48,984 8,943 18,013 (5,269) 9,079 18,623 43,715 (1,195) 12/16/2016 Princeton, New Jersey 20,700 32,126 — — 1,920 431 20,700 34,046 431 (3,972) 6/30/2014 Dulles, Virginia 3,154 29,583 — — 42,852 3,852 3,154 72,435 3,852 (18,586) 10/6/2017 Ashburn, Virginia (2) — — 53,009 17,325 63,245 131,942 17,325 63,245 184,951 (1,704) 8/9/2017 & 10/23/2017 Phoenix, Arizona (2) — — 24,668 — — 4,894 — — 29,562 — 8/11/2017 Hillsboro, Oregon (2) — — 25,657 — — 14,178 — — 39,835 — 10/3/2017 Miami, Florida 1,777 6,955 — — 24,080 90 1,777 31,035 90 (11,044) 3/6/2008 Lenexa, Kansas 400 3,100 — 36 735 — 436 3,835 — (457) 6/3/2011 Manassas, Virginia (1) (5) — — 24,626 — — 20,568 — — 45,194 — 3/2/2018 $ 51,156 $ 303,614 $ 208,608 $ 54,385 $ 1,569,440 $ 572,099 $ 105,541 $ 1,873,054 $ 780,707 $ (436,700) Leased Properties Leased Facilities acquired in 2015 — 59,087 — — (37,471) 382 — 21,616 382 (18,586) 6/16/2015 Jersey City, New Jersey — 1,985 — — 19,745 8,952 — 21,730 8,952 (11,757) 11/1/2006 Overland Park, Kansas — — — — 851 22 — 851 22 (601) $ — $ 61,072 $ — $ — $ (16,875) $ 9,356 $ — $ 44,197 $ 9,356 $ (30,944) $ 51,156 $ 364,686 $ 208,608 $ 54,385 $ 1,552,565 $ 581,455 $ 105,541 $ 1,917,251 $ 790,064 $ (467,644) (1) See Note 2 ‘Significant Accounting Policies’ for information regarding asset lives on which depreciation and amortization are calculated. (2) Represent land purchases. Land acquisition costs, as well as subsequent development costs, are included within construction in progress until development on the land has ended and the asset is ready for its intended use. The aggregate gross cost of the Company’s properties for federal income tax purposes was $3.03 billion (unaudited) as of December 31, 2018. The following table reconciles the historical cost and accumulated depreciation for the years ended December 31, 2018, 2017 and 2016 (in thousands): Year Ended December 31, 2018 2017 2016 Property Balance, beginning of period $ 2,357,322 $ 1,964,857 $ 1,583,153 Disposals (43,616) (18,198) (8,946) Additions (acquisitions and improvements) 499,150 410,663 390,650 Balance, end of period $ 2,812,856 $ 2,357,322 $ 1,964,857 Accumulated depreciation Balance, beginning of period $ (394,823) $ (317,834) $ (239,936) Disposals 30,139 13,970 6,761 Additions (depreciation and amortization expense) (102,960) (90,959) (84,659) Balance, end of period $ (467,644) $ (394,823) $ (317,834)

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2018
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 810, Consolidation , and the Company is the primary beneficiary of the VIE. As discussed below, the Company’s only material asset is its ownership interest in the Operating Partnership, and consequently, all of its assets and liabilities represent those assets and liabilities of the Operating Partnership. The Company’s debt is an obligation of the Operating Partnership where the creditors may have recourse, under certain circumstances, against the credit of the Company. QTS is the sole general partner of the Operating Partnership, and its only material asset consists of its ownership interest in the Operating Partnership. Management operates QTS and the Operating Partnership as one business. The management of QTS consists of the same employees as the management of the Operating Partnership. QTS does not conduct business itself, other than acting as the sole general partner of the Operating Partnership and issuing public equity from time to time. QTS has not issued or guaranteed any indebtedness. Except for net proceeds from public equity issuances by QTS, which are contributed to the Operating Partnership in exchange for units of limited partnership interest of the Operating Partnership, the Operating Partnership generates all remaining capital required by the business through its operations, the direct or indirect incurrence of indebtedness, and the issuance of partnership units. Therefore, as general partner with control of the Operating Partnership, QTS consolidates the Operating Partnership for financial reporting purposes. 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 4.75% Senior Notes due 2025 and the unsecured credit facility, both discussed in Note 6, are fully, unconditionally, and jointly and severally guaranteed by 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 Operating Partnership, QTS Finance Corporation (the co-issuer of the 4.75% Senior Notes due 2025) or any subsidiary guarantor. The indenture governing the 4.75% 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 subsidiaries. This includes the operating results of the Operating Partnership for all periods presented.
Use of Estimates	Use of Estimates – The preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. Significant items subject to such estimates and assumptions include the useful lives of fixed assets, allowances for doubtful accounts and deferred tax assets and the valuation of derivatives, real estate assets, acquired intangible assets and certain accruals.
Principles of Consolidation	Principles of Consolidation – The consolidated financial statements of QTS Realty Trust, Inc. include the accounts of QTS Realty Trust, Inc. and its controlled subsidiaries. The consolidated financial statements of QualityTech, LP include the accounts of QualityTech, LP and its subsidiaries. All significant intercompany accounts and transactions have been eliminated in the financial statements.
Real Estate Assets	Real Estate Assets – Real estate assets are reported at cost. All capital improvements for the income-producing properties that extend their useful lives are capitalized to individual property improvements and depreciated over their estimated useful lives. Depreciation for real estate assets is generally provided on a straight-line basis over 40 years from the date the property was placed in service. Property improvements are depreciated on a straight-line basis over the life of the respective improvement ranging from 20 to 40 years from the date the components were placed in service. Leasehold improvements are depreciated over the lesser of 20 years or through the end of the respective life of the lease. Repairs and maintenance costs are expensed as incurred. For the year ended December 31, 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. For the year ended December 31, 2016, depreciation expense related to real estate assets and non-real estate assets was $77.5 million and $13.1 million, respectively, for a total of $90.6 million. The Company capitalizes certain 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 costs) begins when development efforts commence and ends when the asset is ready for its intended use. Capitalization of such costs, excluding interest, aggregated to $17. 4 million, $12.7 million and $11.0 million for the years ended December 31, 2018, 2017 and 2016 respectively. Interest is capitalized during the period of development by applying the Company’s 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 $26.8 million, $14.3 million and $11.4 million for the years ended December 31, 2018, 2017 and 2016, respectively.
Acquisitions and Sales	Acquisitions and Sales – Acquisitions of real estate and other entities are either accounted for as asset acquisitions or business combinations depending on facts and circumstances. When substantially all of the fair value of gross assets acquired is concentrated in a single identifiable asset or a group of similar identifiable assets, the transaction is accounted for as an asset acquisition. In an asset acquisition, the purchase price paid for assets acquired is allocated between identified tangible and intangible assets acquired based on relative fair value. Transaction costs associated with asset acquisitions are capitalized. When substantially all of the fair value of assets acquired is not concentrated in a group of similar identifiable assets, the set of assets will generally be considered a business. When accounting for business combinations purchase accounting is applied to the assets and liabilities related to all real estate investments acquired in accordance with the accounting requirements of ASC 805, Business Combinations , which requires the recording of net assets of acquired businesses at fair value. The fair value of the consideration transferred is assigned to the acquired tangible assets, consisting primarily of land, construction in progress, building and improvements, and identified intangible assets and liabilities, consisting of the value of above-market and below-market leases, value of in-place leases, value of customer relationships, trade names, software intangibles and capital leases. The excess of the fair value of liabilities assumed, common stock issued and cash paid over the fair value of identifiable assets acquired is allocated to goodwill, which is not amortized by the Company. Transaction costs associated with business combinations are expensed as incurred. In developing estimates of fair value of acquired assets and assumed liabilities, management analyzed 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. This amortization expense is accounted for as real estate amortization expense. Acquired customer relationships are amortized as amortization expense on a straight-line basis over the expected life of the customer relationship. This amortization expense is 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 the Company is a lessor as well as a reduction to or increase in rent expense over the remaining lease terms in the case of the Company as 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. The Company accounts for the sale of assets under Financial Accounting Standards Board (“FASB”) Accounting Standards Update (“ASU”) No. 2017-05, Other Income—Gains and Losses from the Derecognition of Nonfinancial Assets (Subtopic 610-20), which provides for recognition or derecognition based on transfer of ownership. During the year ended December 31, 2018, the Company recognized a $7.0 million net loss on sale of equipment associated with the Company’s strategic growth plan. The loss on disposal is included within the “Restructuring” line item of the consolidated statements of operations.
Impairment of Long-Lived and Intangible Assets	Impairment of Long-Lived Assets, Intangible Assets and Goodwill – The Company reviews its long-lived assets and intangible assets for impairment when events or changes in circumstances indicate that the carrying amount of the assets may not be recoverable. Recoverability of assets to be held and used is measured by comparison of the carrying amount to the future net cash flows, undiscounted and without interest, expected to be generated by the asset group. If the net carrying value of the asset exceeds the value of the undiscounted cash flows, the fair value of the asset is assessed and may be considered impaired. An impairment loss is recognized based on the excess of the carrying amount of the impaired asset over its fair value. For the year ended December 31, 2018, the Company recognized $8.8 million of impairment losses related to certain product-related assets, which is included in the “Restructuring” line item of the consolidated statement of operations. For the year ended December 31, 2017, the Company recognized a $1.6 million impairment related to equipment used to support its cloud and managed service platform, which is included in the “Transaction, integration and impairment costs” line item of the consolidated statement of operations. No impairment losses were recorded for the year ended December 31, 2016. 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 the Company performed as of October 1, 2018, the Company determined qualitatively that it is not more likely than not that the fair value of the Company’s one reporting unit was less than the carrying amount, thus it did not perform a quantitative analysis. As the Company continues to operate and assess its goodwill at the consolidated level and its market capitalization significantly exceeds its net asset value, further analysis was not deemed necessary as of December 31, 2018.
Assets Held for Sale	Assets Held for Sale – As of December 31, 2018, the Company believed it was probable that it would complete a sale of the Manassas facility to a joint venture within one year and accordingly reclassified certain assets, as well as liabilities associated with those assets, as held for sale. The asset value of $71.8 million associated with the held for sale assets is included within the “Assets held for sale” line item of the consolidated statements of financial position and primarily consists of construction in progress. The liability value of $24.3 million associated with the held for sale liabilities is included within the “Liabilities held for sale” line item of the consolidated statements of financial position and primarily consists of accounts payable and accrued liabilities associated with construction in progress assets. See Note 19 for further discussion of the joint venture.
Cash and Cash Equivalents	Cash and Cash Equivalents – The Company considers all demand deposits and money market accounts purchased with a maturity date of three months or less at the date of purchase to be cash equivalents. The Company’s account balances at one or more institutions periodically exceed the Federal Deposit Insurance Corporation (“FDIC”) insurance coverage and, as a result, there is concentration of credit risk related to amounts on deposit in excess of FDIC coverage. The Company mitigates this risk by depositing a majority of its funds with several major financial institutions. The Company also has not experienced any losses and does not believe that the risk is significant.
Deferred Costs	Deferred Costs – Deferred costs, net, on the Company’s 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 sheet, were $3.9 million, $3.6 million and $3.3 million for the years ended December 31, 2018, 2017 and 2016, respectively. During the year ended December 31, 2018, the Company wrote off unamortized financing costs of $0.6 million to the income statement in connection with the modification of its unsecured credit facility in November 2018 whereby the company 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, the Company wrote off unamortized financing costs of $5.2 million to the income statement primarily in connection with the replacement of its $300 million 5.875% senior notes with the $400 million of 4.75% notes. During the year ended December 31, 2016, the Company wrote off unamortized financing costs of $0.2 million to the income statement in connection with the modification of its unsecured credit facility in December 2016 whereby the company increased the total capacity and extended the term for an additional year. Deferred financing costs presented as assets on the balance sheet related to revolving debt arrangements, net of accumulated amortization are as follows: December 31, December 31, (dollars in thousands) 2018 2017 Deferred financing costs $ 11,530 $ 9,775 Accumulated amortization (3,859) (1,908) Deferred financing costs, net $ 7,671 $ 7,867 Deferred financing costs presented as offsets to the associated liabilities on the balance sheets related to fixed term debt arrangements, net of accumulated amortization, are as follows: December 31, December 31, (dollars in thousands) 2018 2017 Deferred financing costs $ 14,501 $ 12,675 Accumulated amortization (2,944) (1,039) Deferred financing costs, net $ 11,557 $ 11,636 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. These costs are incurred when the Company executes lease agreements and represent only incremental costs that would not have been incurred if the lease agreement had not been executed. The Company incurs the same incremental costs to obtain managed services and cloud contracts with customers that are accounted for pursuant to ASC 606, Revenue from Contracts with Customers . These costs are accounted for under ASC 340-40, Other Assets and Deferred Costs , which includes a similar framework for capitalization that is applied to the Company’s leasing contracts as only the direct and incremental costs of obtaining a revenue contract are capitalized. Because the framework of accounting for these costs and the underlying nature of the costs are the same for the Company’s revenue and lease contracts, the costs are presented on a combined basis within the Company’s financial statements and within the below table. Both revenue and leasing commissions are capitalized and generally amortized over the term of the related leases or the expected term of the contract using the straight-line method. If a customer lease terminates prior to the expiration of its initial term, any unamortized initial direct costs related to the lease are written off to amortization expense. Amortization of deferred leasing costs totaled $21.3 million, $18.5 million and $15.2 million for the years ended December 31, 2018, 2017 and 2016, respectively. Deferred leasing costs, net of accumulated amortization are as follows: December 31, December 31, (dollars in thousands) 2018 2017 Deferred leasing costs $ 63,018 $ 54,868 Accumulated amortization (25,593) (20,956) Deferred leasing costs, net $ 37,425 $ 33,912
Revenue Recognition	Revenue Recognition – In May 2014, the Financial Accounting Standards Board (“FASB”) issued guidance codified in Accounting Standards Codification (“ASC”) Topic 606, Revenue from Contracts with Customers , which supersedes the prior revenue recognition requirements in ASC Topic 605, Revenue Recognition . Under this new guidance, entities should recognize revenues to depict the transfer of promised goods or services to customers in an amount that reflects the consideration the entity expects to receive in exchange for those goods or services. This standard also requires enhanced disclosures. The standard is effective for annual and interim periods beginning after December 15, 2017. Retrospective and modified retrospective application is allowed. The Company adopted ASC Topic 606 effective January 1, 2018, and elected the modified retrospective transition approach. The adoption did not result in a cumulative catch-up adjustment to opening equity and does not change the recognition pattern of the Company’s operating revenues, a significant portion of which are recognized as rental income in accordance with ASC 840, Leases . Under ASC 606, disclosures are required to provide information on the nature, amount, timing, and uncertainty of revenue, certain costs, and cash flows arising from contracts with customers. The Company derives its revenues from leases with customers for data center space which include lease rental revenue components and nonlease revenue components, such as power, cloud and managed services. A description of each of the Company’s disaggregated revenue streams as presented on the face of the consolidated statements of operations is as follows: Rental Revenue The Company’s 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. The Company does 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 the Company to provide a series of distinct services of standing ready to deliver the power over the contracted term which is co-terminus with the lease. The Company recognizes revenue from these nonlease fixed power components over time on a straight-line basis in the same manner as the lease components of the contract as the customer simultaneously receives and consumes the power benefits provided over the lease term. Rental revenue also includes amortization of set-up fees which are amortized over the term of the respective lease as discussed below. Recoveries from Customers Certain customer leases contain provisions under which customers reimburse the Company 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 are nonlease components and relate specifically to the Company’s variable power arrangements, whereby customers pay variable monthly fees for the specific amount of power utilized at the current utility rates. The Company’s 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. the Company provides power to its customers) and customers utilize the power. Reimbursement of real estate taxes, insurance, common area maintenance, or other operating expenses are accounted for as executory costs under lease guidance and are recognized as revenue in the period that the associated expenses are recognized. Cloud and Managed Services The Company, through its TRS, may provide both its cloud product and use of its managed services to its customers on an individual or combined basis. In both its 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 the Company accounts for the services as a series of distinct services. Service fee revenue is recognized as the revenue is earned, which generally coincides with the services being provided. As the Company has 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, the Company recognizes monthly revenue for the amount invoiced. With respect to the transaction price allocated to remaining performance obligations within the Company’s cloud and managed service contracts, the Company has elected to use the optional exemption provided by the standard whereby the Company is not required to estimate the total transaction price allocated to remaining performance obligations as the Company applies 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. Other Other revenue primarily consists of 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 $29.7 million and $23.4 million as of December 31, 2018 and December 31, 2017, respectively.
Advance Rents and Security Deposits	Advance Rents and Security Deposits – Advance rents, typically prepayment of the following month’s rent, consist of payments received from customers prior to the time they are earned and are recognized as revenue in subsequent periods when earned. Security deposits are collected from customers at the lease origination and are generally refunded to customers upon lease expiration.
Deferred Income	Deferred Income – Deferred income generally results from non-refundable charges paid by the customer at lease inception to prepare their space for occupancy. The Company records this initial payment, commonly referred to as set-up fees, as a deferred income liability which amortizes into rental revenue over the term of the related lease on a straight-line basis. Deferred income was $33.2 million, $25.3 million and $22.0 million as of December 31, 2018, 2017 and 2016, respectively. Additionally, $12.5 million, $10.7 million and $9.4 million of deferred income was amortized into revenue for the years ended December 31, 2018, 2017 and 2016, respectively.
Equity-based Compensation	Equity-based Compensation – Equity-based compensation costs are measured based upon their estimated fair value on the date of grant or modification and amortized ratably over their respective service periods. We have elected to account for forfeitures as they occur. Equity-based compensation expense net of forfeited and repurchased awards was $15.0 million, $13.9 million and $10.6 million for the years ended December 31, 2018, 2017 and 2016, respectively. Equity-based compensation expense for the year ended December 31, 2018 excludes $3.1 million of equity-based compensation expense associated with the acceleration of equity awards related to certain employees impacted by the Company’s strategic growth plan. The aforementioned equity-based compensation expense is included in the “Restructuring” expense line item on the consolidated statements of operations.
Allowance for Uncollectible Accounts Receivable	Allowance for Uncollectible Accounts Receivable – Rents receivable are recognized when due and are carried at cost, less an allowance for doubtful accounts. The Company records a provision for losses on rents receivable equal to the estimated uncollectible accounts, which is based on management’s historical experience and a review of the current status of the Company’s receivables. As necessary, the Company also establishes an appropriate allowance for doubtful accounts for receivables arising from the straight-lining of rents. The aggregate allowance for doubtful accounts was $3.8 million and $11.5 million as of December 31, 2018 and December 31, 2017, respectively.
Capital Leases and Lease Financing Obligations	Capital Leases and Lease Financing Obligations – The Company evaluates leased real estate to determine whether the lease should be classified as a capital or operating lease in accordance with U.S. GAAP. The Company periodically enters into capital leases for certain data center equipment as well as fiber optic transmission cabling. In addition, through its acquisition of Carpathia Hosting, Inc. (“Carpathia”) on June 16, 2015, the Company is party to capital leases for property and equipment, as well as certain financing obligations. The outstanding liabilities for the capital leases were $2.7 million and $7.8 million as of December 31, 2018 and 2017, respectively. The outstanding liabilities for the lease financing obligations were $0.1 million and $0.9 million as of December 31, 2018 and 2017, respectively. The net book value of the assets associated with these leases was approximately $1.8 million and $14.7 million as of December 31, 2018 and 2017, respectively. Depreciation related to the associated assets is included in depreciation and amortization expense in the Statements of Operations. See Note 6 for further discussion of capital leases and lease financing obligations.
Segment Information	Segment Information – The Company manages its business as one operating segment and thus one reportable segment consisting of a portfolio of investments in data centers located primarily in the United States.
Customer Concentrations	Customer Concentrations – As of December 31, 2018, one of the Company’s customers represented 12.8% of its total monthly rental revenue. No other customers exceeded 5% of total monthly rental revenue. As of December 31, 2018, two of the Company’s customers exceeded 5% of total accounts receivable. In aggregate, these two customers accounted for 25% of total accounts receivable. Both of these customers individually exceeded 10% of total accounts receivable.
Income Taxes	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. For the taxable REIT subsidiaries, income taxes are accounted for under the asset and liability method in accordance with ASC 740. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases and operating loss and tax credit carryforwards. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to be recovered or settled. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. We consider whether it is more likely than not that some portion or all of the deferred tax assets will be realized. It is possible that some or all of our deferred tax assets could ultimately expire unused. The Company establishes valuation allowances against deferred tax assets when the ability to fully utilize these benefits is determined to be uncertain. The components of income tax provision from continuing operations are: For the Year Ended December 31, 2018 2017 2016 Current: U.S. federal $ (50) $ 42 $ (356) U.S. State 395 297 20 Outside United States 78 44 33 Total Current 423 383 (303) Deferred: U.S. federal (3,727) (9,734) (8,796) U.S. State (64) (427) (877) Outside United States — — — Total Deferred (3,791) (10,161) (9,673) Total $ (3,368) $ (9,778) $ (9,976) Temporary differences and carry forwards which give rise to the deferred tax assets and liabilities are as follows: For the Year Ended December 31, 2018 2017 2016 Deferred tax liabilities Property and equipment $ (3,089) $ (4,940) $ (15,031) Goodwill (1,953) (1,396) (1,290) Intangibles (11,910) (13,606) (24,244) Other (1,049) (1,132) (1,386) Gross deferred tax liabilities (18,001) (21,074) (41,951) Deferred tax assets Net operating loss carryforwards 17,610 8,888 18,035 Deferred revenue and setup charges 3,171 3,435 4,323 Leases 1 453 2,154 Credits 287 543 492 Bad debt reserve 409 2,250 41 Interest expense carryforward IRC Sec. 163(j) 2,253 — — Other 1,534 1,607 2,114 Gross deferred tax assets 25,265 17,176 27,159 Net deferred tax liability 7,264 (3,898) (14,792) Valuation allowance (8,361) (713) (393) Net deferred tax liability $ (1,097) $ (4,611) $ (15,185) The taxable REIT subsidiaries currently have net operating loss carryforwards related to federal income taxes of $33.4 million that expire in 11-18 years and $32.6 million which have no expiration. The taxable REIT subsidiaries also have $66.3 million of net operating loss carryforwards relating to state income taxes that expire in 2-20 years. The Company’s interest expense carryforward of $8.8 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, 2018 2017 2016 TRS Statutory rate applied to pre-tax loss $ (9,656) $ (5,109) $ (7,299) Permanent differences, net 97 (284) (2,021) State income tax, net of federal benefit (1,430) (388) (689) Foreign income tax 78 44 33 Federal and State rate change (146) (3,251) — Contribution of Assets to TRS — (866) — Other 41 (244) — Valuation allowance increase (decrease) 7,648 320 — Total tax benefit $ (3,368) $ (9,778) $ (9,976) Effective tax rate 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 sheet 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 ending 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 ending 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 accounted for income tax effects of the Act in the reporting period ending 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, 2018, 2017 and 2016, 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, 2018, 2017 and 2016, the Company had accrued no such interest or penalties. The Company is currently not under examination by the Internal Revenue Service or any state jurisdictions. Tax years ending after December 31, 2014 remain subject to examination and assessment, state limitation periods included. Tax years ending December 31, 2009 through December 31, 2013 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, 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, 2018 and 2017, valuation allowances of $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 $7.7 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 and a change in the evidence available related to the scheduled reversal of taxable temporary differences. Additionally, 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.
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 – ASC Topic 820, Fair Value Measurement , emphasizes that fair-value is a market-based measurement, not an entity-specific measurement. Therefore, a fair-value measurement should be determined based on the assumptions that market participants would use in pricing the asset or liability. As a basis for considering market participant assumptions in fair-value measurements, a fair-value hierarchy is established that distinguishes between market participant assumptions based on market data obtained from sources independent of the reporting entity (observable inputs that are classified within Levels 1 and 2 of the hierarchy) and the reporting entity’s own assumptions about market participant assumptions (unobservable inputs classified within Level 3 of the hierarchy). Level 1 inputs utilize quoted prices (unadjusted) in active markets for identical assets or liabilities that the Company has 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. The Company’s 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, 2018, the Company valued its interest rate swaps primarily utilizing Level 2 inputs. See Note 17 – ‘Fair Value of Financial Instruments’ for additional details.
New Accounting Pronouncements	New Accounting Pronouncements In February 2016, and further amended in 2018, the FASB issued ASU 2016-02, Leases (Topic 842) , which supersedes the current lease guidance in ASC 840, Lease s. The core principle of Topic 842 requires lessees to recognize the assets and liabilities that arise from nearly all leases in the statement of financial position. Accounting applied by lessors will remain largely consistent with previous guidance, with additional changes set to align lessor accounting with the revised lessee model and the FASB’s revenue recognition guidance in Topic 606. The amendments in ASC 840 are effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. Early adoption is permitted. In July 2018, the FASB issued ASU 2018-11, Leases – Targeted Improvements (Topic 842), which updated the lease standard to include practical expedients that remove the requirement to restate prior period financial statements upon adoption of the standard as well as a practical expedient which allows lessors not to separate non-lease components from the related lease components if both the timing and pattern of transfer are the same for the non-lease component(s) and related lease component and the combined single lease component would be classified as an operating lease. The Company plans to adopt ASC 842 effective January 1, 2019 using the modified retrospective approach, which applies the provisions of the new guidance at the effective date without adjusting the comparative periods presented. The Company will elect the package of practical expedients permitted under the transition guidance within the new standard, which allows the Company 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. In addition, the Company will not elect to use hindsight during transition. As lessee, the Company does not anticipate the classification of its leases to change but will recognize a new initial lease liability and right-of-use asset on the consolidated balance sheet for all operating leases which is expected to approximate $75 million to $80 million. This amount does not include leases that will commence subsequent to the initial adoption of ASC 842, one of which is a finance lease obligation the Company expects to approximate $45 million. As lessor, accounting for our leases will remain largely unchanged, apart from the narrower definition of initial direct costs that can be capitalized. The new lease standard more narrowly defines initial direct costs as only costs that are incremental at the signing of a lease. As the Company does not currently capitalize non-incremental costs, it expects the impact of this change to be immaterial to the financial statements. Additionally, from a lessor perspective, the transition relief is expected to alleviate the Company’s need to separate lease from certain non-lease components within its rental revenue contracts. The Company will disclose any changes to this analysis as identified. In October 2016, the FASB issued ASU 2016-16, Accounting for Income Taxes: Intra-Entity Asset Transfers of Assets Other than Inventory . Under current GAAP, the tax effects of intra-entity asset transfers are deferred until the transferred asset is sold to a third party or otherwise recovered through use. The new guidance eliminates the exception for all intra-entity sales of assets other than inventory. As a result, a reporting entity would recognize the tax expense from the sale of the asset in the seller’s tax jurisdiction when the transfer occurs, even though the pre-tax effects of that transaction are eliminated in consolidation. Any deferred tax asset that arises in the buyer’s jurisdiction would also be recognized at the time of the transfer. The new guidance will be effective for public business entities in fiscal years beginning after December 15, 2017, including interim periods within those years. The Company adopted the standard in 2018, and the provisions of the standard have not had a material impact on its consolidated financial statements. In August 2017, the FASB issued ASU 2017-12, Derivatives and Hedging (Topic 815): Targeted Improvements to Accounting for Hedging Activities. The amendments in ASU 2017-12 change the recognition and presentation requirements of hedge accounting, including the elimination of the requirement to separately measure and report hedge ineffectiveness and the addition of a requirement to present all items that affect earnings in the same income statement line item as the hedged item. ASU 2017-12 also provides new alternatives for: applying hedge accounting to additional hedging strategies; measuring the hedged item in fair value hedges of interest rate risk; reducing the cost and complexity of applying hedge accounting by easing the requirements for effectiveness testing, hedge documentation and application of the critical terms match method; and reducing the risk of material error correction if a company applies the shortcut method inappropriately. The guidance is effective for public entities for fiscal years beginning after December 15, 2018, and interim periods within those fiscal years. Early application is permitted. The Company elected to early adopt this standard effective October 1, 2018, and the provisions of this standard did not have a material impact on its consolidated financial statements. In August 2018, the FASB issued ASU 2018-13, Fair Value Measurement (Topic 820): Disclosure Framework – Changes to the Disclosure Requirements for Fair Value Measurement. The amendments in ASU 2018-13 eliminate the requirements to disclose the amount and reasons for transfers between Level 1 and Level 2 of the fair value hierarchy, valuation processes for Level 3 fair value measurements, and policy for timing of transfers between levels. ASU 2018-13 also provides clarification in the measurement uncertainty disclosure by explaining that the disclosure is to communicate information about the uncertainty in measurement as of the reporting date. In addition, ASU 2018-13 added the following requirements: changes in unrealized gains and losses for the period included in other comprehensive income for recurring Level 3 fair value measurements held at the end of the reporting period; and range and weighted average of significant unobservable inputs used in Level 3 fair value measurements. Finally, ASU 2018-13 updated language to further encourage entities to apply materiality when considering de minimus for disclosure requirements. The guidance will be applied retrospectively for fiscal years beginning after December 15, 2019, and interim periods within those fiscal years, with the exception of amendments to changes in unrealized gains and losses, the range and weighted average of significant unobservable inputs used for Level 3 fair value measurements, and the narrative description of measurement uncertainty which will be applied prospectively. Early adoption is permitted. The Company is currently assessing the impact of this standard on its consolidated financial statements. In August 2018, the FASB issued ASU 2018-15, Intangibles – Goodwill and Other – Internal-Use Software ( Subtopic 350-40): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement that is a Service Contract. The amendments in ASU 2018-15 require an entity in a service contract hosting arrangement apply Subtopic 350-40 to identify costs to capitalize or expense related to the service contract. ASU 2018-15 also requires the entity to capitalize the implementation costs of the service contract hosting arrangement and amortize such costs over the life of the contract and present the capitalized costs in the same line item as fees associated with the hosting service on the statement of income and statement of cash flows. The guidance will be applied retrospectively for fiscal years beginning after December 15, 2019, and interim periods within those fiscal years, with the exception of all implementation costs incurred after the date of adoption which will be applied prospectively. Early adoption is permitted. The Company is currently assessing the impact of this standard on its consolidated financial statements. In October 2018, the FASB issued guidance codified in ASU 2018-16, Derivatives and Hedging (Topic 815): Inclusion of the Secured Overnight Financing Rate (SOFR) Overnight Index Swap (OIS) Rate as a Benchmark Interest Rate for Hedge Accounting Purposes. ASU 2018-16 permits the use of the OIS rate based on SOFR as a U.S. benchmark interest rate for hedge accounting purposes under Topic 815. The standard will be effective for interim and annual reporting periods beginning after December 15, 2018, with early adoption permitted for entities that have already adopted ASU 2017-12. The Company elected to early adopt this standard concurrent with ASU 2017-12, effective October 1, 2018, and the provisions of this standard did not have a material impact on our consolidated financial statements.

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2018
Deferred Financing Costs, Net of Accumulated Amortization	December 31, December 31, (dollars in thousands) 2018 2017 Deferred financing costs $ 11,530 $ 9,775 Accumulated amortization (3,859) (1,908) Deferred financing costs, net $ 7,671 $ 7,867
Deferred Leasing Costs, Net of Accumulated Amortization	December 31, December 31, (dollars in thousands) 2018 2017 Deferred leasing costs $ 63,018 $ 54,868 Accumulated amortization (25,593) (20,956) Deferred leasing costs, net $ 37,425 $ 33,912
Schedule of Components of Income Tax Expense (Benefit)	For the Year Ended December 31, 2018 2017 2016 Current: U.S. federal $ (50) $ 42 $ (356) U.S. State 395 297 20 Outside United States 78 44 33 Total Current 423 383 (303) Deferred: U.S. federal (3,727) (9,734) (8,796) U.S. State (64) (427) (877) Outside United States — — — Total Deferred (3,791) (10,161) (9,673) Total $ (3,368) $ (9,778) $ (9,976)
Summary of Temporary Differences and Carry Forwards Which Give Rise to the Deferred Tax Assets and Liabilities	For the Year Ended December 31, 2018 2017 2016 Deferred tax liabilities Property and equipment $ (3,089) $ (4,940) $ (15,031) Goodwill (1,953) (1,396) (1,290) Intangibles (11,910) (13,606) (24,244) Other (1,049) (1,132) (1,386) Gross deferred tax liabilities (18,001) (21,074) (41,951) Deferred tax assets Net operating loss carryforwards 17,610 8,888 18,035 Deferred revenue and setup charges 3,171 3,435 4,323 Leases 1 453 2,154 Credits 287 543 492 Bad debt reserve 409 2,250 41 Interest expense carryforward IRC Sec. 163(j) 2,253 — — Other 1,534 1,607 2,114 Gross deferred tax assets 25,265 17,176 27,159 Net deferred tax liability 7,264 (3,898) (14,792) Valuation allowance (8,361) (713) (393) Net deferred tax liability $ (1,097) $ (4,611) $ (15,185)
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, 2018 2017 2016 TRS Statutory rate applied to pre-tax loss $ (9,656) $ (5,109) $ (7,299) Permanent differences, net 97 (284) (2,021) State income tax, net of federal benefit (1,430) (388) (689) Foreign income tax 78 44 33 Federal and State rate change (146) (3,251) — Contribution of Assets to TRS — (866) — Other 41 (244) — Valuation allowance increase (decrease) 7,648 320 — Total tax benefit $ (3,368) $ (9,778) $ (9,976) Effective tax rate
Fixed debt arrangements
Deferred Financing Costs, Net of Accumulated Amortization	December 31, December 31, (dollars in thousands) 2018 2017 Deferred financing costs $ 14,501 $ 12,675 Accumulated amortization (2,944) (1,039) Deferred financing costs, net $ 11,557 $ 11,636

Acquisitions (Tables)

Acquisitions (Tables)	12 Months Ended
	Dec. 31, 2018
Fort Worth Facility
Schedule of the Preliminary Allocation of the Fair Value of Assets Acquired and Liabilities Assumed in Acquisition	In December 2017, the Company finalized the Fort Worth purchase price allocation. The following table summarizes the consideration for the Fort Worth facility and the final allocation of the fair value of assets acquired and liabilities assumed at the acquisition date (in thousands): Final Fort Worth Allocation as of Preliminary Allocation Reported as of December 31, 2016 Adjustments to Fair Value Land $ 136 $ 136 $ — Buildings and improvements 610 610 — Construction in progress 48,987 48,984 3 Acquired intangibles 237 240 (3) Deferred costs 23 23 — Other assets 7 7 — Net Working Capital 86 86 — Total identifiable assets acquired $ 50,086 $ 50,086 $ —
Piscataway Facility
Schedule of the Preliminary Allocation of the Fair Value of Assets Acquired and Liabilities Assumed in Acquisition	In June 2017, the Company finalized the Piscataway purchase price allocation. The following table summarizes the consideration for the Piscataway facility and the final allocation of the fair value of assets acquired and liabilities assumed at the acquisition date (in thousands): Final Piscataway Allocation as of Preliminary Allocation Reported as of June 30, 2016 Adjustments to Fair Value Land $ 7,466 $ 7,440 $ 26 Buildings and improvements 80,366 78,370 1,996 Construction in progress 13,900 13,900 — Acquired intangibles 19,581 21,668 (2,087) Deferred costs 4,390 4,084 306 Other assets 106 106 — Total identifiable assets acquired 125,809 125,568 241 Acquired below market lease 809 568 241 Net working capital 2,019 2,019 — Total liabilities assumed 2,828 2,587 241 Net identifiable assets acquired $ 122,981 $ 122,981 $ —

Acquired Intangibles Assets a_2

Acquired Intangibles Assets and Liabilities (Tables)	12 Months Ended
	Dec. 31, 2018
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, 2018 December 31, 2017 Useful Lives Gross Accumulated Net Carrying Gross Accumulated Net Carrying Customer Relationships 12 years $ 95,705 $ (28,461) $ 67,244 $ 95,705 $ (20,512) $ 75,193 In-Place Leases 0.5 to 10 years 32,066 (17,670) 14,396 32,066 (12,987) 19,079 Solar Power Agreement (1) 17 years 13,747 (3,639) 10,108 13,747 (2,830) 10,917 Platform Intangible 3 years 9,600 (9,600) — 9,600 (8,133) 1,467 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 4,649 (3,247) 1,402 4,649 (2,328) 2,321 Tradenames 3 years 3,100 (3,100) — 3,100 (2,626) 474 Total Intangible Assets $ 161,168 $ (65,717) $ 95,451 $ 158,867 $ (49,416) $ 109,451 Solar Power Agreement (1) 17 years 13,747 (3,639) 10,108 13,747 (2,830) 10,917 Acquired Unfavorable Leases Acquired below market leases - as Lessor 3 to 4 years 809 (611) 198 809 (375) 434 Acquired above market leases - as Lessee 11 to 12 years 2,453 (767) 1,686 2,453 (550) 1,903 Total Intangible Liabilities (2) $ 17,009 $ (5,017) $ 11,992 $ 17,009 $ (3,755) $ 13,254 (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 statement 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	The estimated amortization of acquired favorable and unfavorable leases for each of the five succeeding fiscal years ending December 31 is as follows (in thousands): Net Rental Revenue Net Rental Expense Increase / (Decrease) 2019 $ 479 $ (166) 2020 647 (166) 2021 46 (166) 2022 17 (166) 2023 17 (166) Thereafter — 1,446 Total $ 1,205 $ 615
Schedule of estimated amortization of all other identified intangible assets	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): 2019 $ 11,965 2020 11,379 2021 10,137 2022 9,910 2023 9,910 Thereafter 28,339 Total $ 81,640

Real Estate Assets and Constr_2

Real Estate Assets and Construction in Progress (Tables)	12 Months Ended
	Dec. 31, 2018
Real Estate Assets and Construction in Progress [Abstract]
Summary of Properties Owned or Leased by the Company	The following is a summary of properties owned or leased by the Company as of December 31, 2018 and 2017 (in thousands): As of December 31, 2018: Property Location Land Buildings and Improvements Construction Total Cost Atlanta, Georgia (Atlanta-Metro) $ 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 (1) 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 (1) (5) — — 45,194 45,194 Santa Clara, California (2) — 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 (3) — 43,347 9,334 52,681 Hillsboro, Oregon (1) — — 39,835 39,835 Phoenix, Arizona (1) — — 29,562 29,562 Other (4) 2,213 35,720 113 38,046 $ 105,541 $ 1,917,251 $ 790,064 $ 2,812,856 (1) 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. (2) Owned facility subject to long-term ground sublease. (3) Includes 10 facilities. All facilities are leased, including those subject to capital leases. (4) Consists of Miami, FL; Lenexa, KS; and Overland Park, KS facilities. (5) Excludes $71.0 million of construction in progress included within the “Assets held for sale” line item of the consolidated balance sheets. As of December 31, 2017: Property Location Land Buildings and Construction Total Cost Atlanta, Georgia (Atlanta-Metro) $ 20,416 $ 452,836 $ 28,614 $ 501,866 Irving, Texas 8,606 276,894 86,320 371,820 Richmond, Virginia 2,180 254,603 61,888 318,671 Chicago, Illinois 9,400 81,463 135,479 226,342 Suwanee, Georgia (Atlanta-Suwanee) 3,521 165,915 3,620 173,056 Piscataway, New Jersey 7,466 83,251 37,807 128,524 Santa Clara, California (1) — 100,028 6,989 107,017 Ashburn, Virginia (2) — — 106,952 106,952 Dulles, Virginia 3,154 76,239 3,565 82,958 Sacramento, California 1,481 64,251 58 65,790 Leased Facilities (3) — 59,460 5,534 64,994 Fort Worth, Texas 9,079 17,894 33,774 60,747 Princeton, New Jersey 20,700 32,948 451 54,099 Hillsboro, Oregon (2) — — 29,278 29,278 Phoenix, Arizona (2) — — 27,402 27,402 Other (4) 2,213 35,505 88 37,806 $ 88,216 $ 1,701,287 $ 567,819 $ 2,357,322 (1) Owned facility subject to long-term ground sublease. (2) Represent land purchases. Land acquisition costs, as well as subsequent development costs, are included within construction in progress until development on the land has ended and the asset is ready for its intended use. (3) Includes 11 facilities. All facilities are leased, including those subject to capital leases. (4) Consists of Miami, FL; Lenexa, KS; Overland Park, KS; and Duluth, GA facilities.

Debt (Tables)

Debt (Tables)	12 Months Ended
	Dec. 31, 2018
Debt [Abstract]
Outstanding Debt Including Capital Leases and Lease Financing Obligations	Below is a listing of the Company’s outstanding debt, including capital leases and lease financing obligations, as of December 31, 2018 and 2017 (in thousands): Weighted Average Coupon Interest Rate at Maturities as of December 31, December 31, December 31, 2018 (1) December 31, 2018 2018 2017 Unsecured Credit Facility Revolving Credit Facility December 17, 2022 $ 252,000 $ 131,000 Term Loan I December 17, 2023 350,000 350,000 Term Loan II April 27, 2024 350,000 350,000 Senior Notes November 15, 2025 400,000 400,000 Lenexa Mortgage May 1, 2022 1,801 1,866 Capital Lease and Lease Financing Obligations 2019 - 2038 2,873 8,699 1,356,674 1,241,565 Less net debt issuance costs (11,557) (11,636) Total outstanding debt, net $ 1,345,117 $ 1,229,929 (1) The coupon interest rates associated with Term Loan I and Term Loan II incorporate the effects of the Company’s interest rate swaps in effect as of December 31, 2018.
Annual Remaining Principal Payment	The annual remaining principal payment requirements as of December 31, 2018 per the contractual maturities and excluding extension options, capital leases and lease financing obligations, are as follows (in thousands): 2019 $ 62 2020 71 2021 74 2022 253,594 2023 350,000 Thereafter 750,000 Total $ 1,353,801
Schedule of Combined Future Payment Obligations, Excluding Interest	The following table summarizes the Company’s combined future payment obligations, excluding interest, as of December 31, 2018, on capital leases and lease financing obligations (in thousands): 2019 $ 994 2020 151 2021 48 2022 44 2023 49 Thereafter 1,587 Total $ 2,873

Interest Rate Swaps (Tables)

Interest Rate Swaps (Tables)	12 Months Ended
	Dec. 31, 2018
Interest Rate Derivative Instruments [Abstract]
Schedule of interest rate derivatives and their fair values	Interest rate derivatives and their fair values as of December 31, 2018 and December 31, 2017 were as follows (in thousands): Fixed One Month Notional Amount LIBOR rate per Fair Value (1) December 31, 2018 December 31, 2017 annum Effective Date Expiration Date December 31, 2018 December 31, 2017 $ 25,000 $ 25,000 January 2, 2018 December 17, 2021 $ 331 $ 100 100,000 100,000 January 2, 2018 December 17, 2021 1,318 401 75,000 75,000 January 2, 2018 December 17, 2021 990 298 50,000 50,000 January 2, 2018 April 27, 2022 667 158 100,000 100,000 January 2, 2018 April 27, 2022 1,341 337 50,000 50,000 January 2, 2018 April 27, 2022 666 155 100,000 — January 2, 2020 December 17, 2023 (782) — 100,000 — January 2, 2020 April 27, 2024 (818) — 200,000 — December 17, 2021 December 17, 2023 (722) — 200,000 — April 27, 2022 April 27, 2024 (648) — $ 1,000,000 $ 400,000 $ 2,343 $ 1,449 (1) Balance recorded in “other assets, net” in the consolidated balance sheets if in an asset position and recorded in “Advance rents, security deposits and other liabilities” in the consolidated balance sheets if in a liability position.

Restructuring (Tables)

Restructuring (Tables)	12 Months Ended
	Dec. 31, 2018
Restructuring [Abstract]
Schedule of changes in the restructuring liability	Restructuring expenses incurred during year ended December 31, 2018 are as follows (in thousands): Equity-Based Compensation and Product-Related Severance Professional Fees and Other Total Restructuring expense $ 6,910 (1) $ 7,740 (2) $ 23,293 (3) $ 37,943 (1) As of December 31, 2018, the outstanding liability for accrued but unpaid severance expense was $0.4 million, which is included in the “Accounts payable and accrued liabilities” line item of the consolidated balance sheets. (2) As of December 31, 2018, there was no outstanding liability for accrued but unpaid equity based compensation and professional fees expense. (3) Product-related and other expenses primarily relate to impairment write-downs of depreciated property as well as losses incurred on the sale of equipment. As of December 31, 2018, the outstanding liability for accrued but unpaid product related and other expense was $2.3 million, which is included in the “Accounts payable and accrued liabilities” line item of the consolidated balance sheets.

Partners' Capital, Equity and_2

Partners' Capital, Equity and Incentive Compensation Plans (Tables)	12 Months Ended
	Dec. 31, 2018
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, 2018, 2017 and 2016: 2010 Equity Incentive Plan 2013 Equity Incentive Plan Weighted Weighted Weighted Weighted Weighted average Weighted average average Number of average Average fair Number of Grant date average fair Restricted Grant date Class O units exercise price value Class RS units value Options exercise price value Stock value Outstanding at January 1, 2016 1,292,899 $ 23.76 $ 3.68 39,875 $ 22.18 867,882 $ 27.80 $ 5.56 394,908 $ 33.82 Granted — — — — — 229,693 45.78 9.91 237,563 45.53 Exercised/Vested (1) (158,088) 21.56 4.18 — — (29,543) 25.70 4.96 (122,136) 33.26 Released from restriction — — — (39,875) 22.18 — — — — — Cancelled/Expired (2) — — — — — (9,735) 32.14 6.95 (95,644) 33.92 Outstanding at December 31, 2016 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 (1) This represents 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. This also represents Class O units which were converted to Class A units and options to purchase Class A common stock which were exercised for their respective columns. (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	2018 2017 2016 Fair value of restricted stock granted $34.03 - $54.01 $48.63 - $51.88 $45.78 - $56.28 Fair value of options granted $5.55 - $5.64 $10.11 - $10.36 $9.57 - $9.97 Expected term (years) 5.5 - 6.0 5.5 - 5.9 5.5 - 5.9 Expected volatility 30.7% - 31.3% Expected dividend yield Expected risk-free interest rates 2.69% - 2.73% 2.12% - 2.18% 1.42% - 1.48%
Summary of Information About Awards Outstanding	The following tables summarize information about awards outstanding as of December 31, 2018. Operating Partnership Awards Outstanding Weighted average Awards remaining Exercise prices outstanding vesting period (years) Class O Units $ 20.00 - 25.00 102,279 — Total Operating Partnership awards outstanding 102,279 QTS Realty Trust, Inc. Awards Outstanding Weighted average Awards remaining Exercise prices outstanding vesting period (years) Restricted stock $ — 420,309 1.7 Options to purchase Class A common stock $ 21.00 - 50.66 2,037,163 1.3 Total QTS Realty Trust, Inc. awards outstanding 2,457,472
Schedule of Quarterly Cash Dividends	Year Ended December 31, 2018 Aggregate Per Share and Dividend/Distribution Record Date Payment Date Per Unit Rate Amount (in millions) Common Stock 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 $ 1.62 $ 93.3 Series A Preferred Stock 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 $ 1.04 $ 4.4 Series B Preferred Stock September 30, 2018 October 15, 2018 $ 1.99 $ 6.3 $ 6.3 Year Ended December 31, 2017 Aggregate Per Share and Dividend/Distribution Record Date Payment Date Per Unit Rate Amount (in millions) Common Stock September 22, 2017 October 5, 2017 $ 0.39 $ 22.2 June 16, 2017 July 6, 2017 0.39 21.6 March 16, 2017 April 5, 2017 0.39 21.4 December 16, 2016 January 5, 2017 0.36 19.7 $ 1.53 $ 84.9

Related Party Transactions (Tab

Related Party Transactions (Tables)	12 Months Ended
	Dec. 31, 2018
Related Party Transactions [Abstract]
Summary of Related Party Transactions	The transactions which occurred during the years ended December 31, 2018, 2017 and 2016 are outlined below (in thousands): December 31, (dollars in thousands) 2018 2017 2016 Tax, utility, insurance and other reimbursement $ 724 $ 796 $ 878 Rent expense 1,014 1,014 1,014 Capital assets acquired 464 561 323 Total $ 2,202 $ 2,371 $ 2,215

Earnings per share of QTS Rea_2

Earnings per share of QTS Realty Trust, Inc. (Tables)	12 Months Ended
	Dec. 31, 2018
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, 2018 2017 2016 Numerator: Net income (loss) $ (7,175) $ 1,457 $ 24,685 Loss (income) attributable to noncontrolling interests 2,715 (175) (3,160) Preferred stock dividends (16,666) — — Earnings attributable to participating securities Net income (loss) available to common stockholders after allocation of participating securities $ (22,073) $ 689 $ 24,685 Denominator: Weighted average shares outstanding - basic 50,433 Effect of Class A partnership units — Effect of Class O units and options to purchase Class A common stock on an "as if" converted basis — Weighted average shares outstanding - diluted 50,433 Basic net income (loss) per share $ (0.44) $ 0.01 $ 0.47 Diluted net income (loss) per share $ (0.44) $ 0.01 $ 0.46 * Note: The table above does not include Class A partnership units of 6.7 million for the year ended December 31, 2018, 0.4 million reflecting the effects of Class O units and options to purchase common stock on an "as if" converted basis for the year ended December 31, 2018, and 3.5 million reflecting the effects of Series B Convertible preferred stock on an “as if” converted basis for the year ended December 31, 2018, as their respective inclusion would have been antidilutive.

Operating Leases, as Lessee (Ta

Operating Leases, as Lessee (Tables)	12 Months Ended
	Dec. 31, 2018
Leases [Abstract]
Future Non-cancellable Minimum Rental Payments Required Under Operating Leases and/or Licenses	The future non-cancellable minimum rental payments required under operating leases and/or licenses at December 31, 2018 are as follows (in thousands): Year Ending December 31, 2019 $ 14,778 2020 11,128 2021 11,008 2022 10,161 2023 10,250 Thereafter 57,221 Total $ 114,546

Contracts with Customers (Table

Contracts with Customers (Table)	12 Months Ended
	Dec. 31, 2018
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 (inclusive of payments for contracts which have not yet commenced, and exclusive of recoveries of operating costs from customers) are as follows for the years ending December 31 (in thousands): Year Ending December 31, 2019 $ 355,440 2020 291,162 2021 232,905 2022 152,069 2023 84,368 Thereafter 112,889 Total $ 1,228,833

Quarterly Financial Informati_2

Quarterly Financial Information (Tables)	12 Months Ended
	Dec. 31, 2018
Summary of Selected Quarterly Information	The tables below reflect the selected quarterly information for the years ended December 31, 2018 and 2017 for QTS (in thousands except share data): Three Months Ended December 31, September 30, June 30, March 31, 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) 2017 Revenues $ 118,911 $ 113,767 $ 107,868 $ 105,964 Operating income 7,553 12,833 10,826 10,915 Net income (loss) (16,113) 7,394 4,608 5,568 Net income (loss) attributable to QTS Realty Trust, Inc. (14,142) 6,507 4,040 4,877 Net income (loss) attributable to common stockholders (14,142) 6,507 4,040 4,877 Net income (loss) per share attributable to common shares - basic (0.29) 0.13 0.08 0.10 Net income (loss) per share attributable to common shares - diluted (0.29) 0.13 0.08 0.10
Qualitytech, LP
Summary of Selected Quarterly Information	The table below reflects the selected quarterly information for the years ended December 31, 2018 and 2017 for the Operating Partnership (in thousands): Three Months Ended December 31, September 30, June 30, March 31, 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) 2017 Revenues $ 118,911 $ 113,767 $ 107,868 $ 105,964 Operating income 7,553 12,833 10,826 10,915 Net income (16,113) 7,394 4,608 5,568 Net income (loss) attributable to common unitholders (16,113) 7,394 4,608 5,568

Description of Business (Detail

Description of Business (Details)	12 Months Ended
	Dec. 31, 2018property
Organization And Description Of Business [Line Items]
Number of properties	25
QualityTech LP
Organization And Description Of Business [Line Items]
Limited Liability Company (LLC) or Limited Partnership (LP), Managing Member or General Partner, Ownership Interest	88.50%

Summary of Significant Accoun_4

Summary of Significant Accounting Policies (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Summary Of Significant Accounting Policies [Line Items]
Payments Related to Tax Withholding for Share-based Compensation	$ 2,205	$ 4,725	$ 2,584
Proceeds from Stock Options Exercised	$ 246	4,972	858
Useful life of property	40 years
Depreciation expense from operation	$ 113,500	104,300	90,600
Real estate cost capitalized excluding interest cost	17,400	12,700	11,000
Real estate interest cost capitalized incurred	26,800	$ 14,300	11,400
Impairment losses	8,800
Assets held for sale	71,800
Liabilities held for sale	$ 24,349
Term Loan Maturing 2025
Summary Of Significant Accounting Policies [Line Items]
Interest rate		4.75%
Senior Notes 4.75 Due 2025
Summary Of Significant Accounting Policies [Line Items]
Interest rate	4.75%
Real Estate Assets
Summary Of Significant Accounting Policies [Line Items]
Depreciation expense from operation	$ 101,200	$ 90,100	77,500
Non-Real Estate Assets
Summary Of Significant Accounting Policies [Line Items]
Depreciation expense from operation	$ 12,300	14,200	13,100
Minimum | Real Property
Summary Of Significant Accounting Policies [Line Items]
Useful life of property	20 years
Maximum | Real Property
Summary Of Significant Accounting Policies [Line Items]
Useful life of property	40 years
Maximum | Leasehold Improvements
Summary Of Significant Accounting Policies [Line Items]
Useful life of property	20 years
Restructuring Charges [Member]
Summary Of Significant Accounting Policies [Line Items]
Gain / (Loss) on disposal of equipment	$ (7,000)
Transaction Integration And Impairment Costs [Member]
Summary Of Significant Accounting Policies [Line Items]
Impairment losses		$ 1,600	$ 0

Summary of Significant Accoun_5

Summary of Significant Accounting Policies (Additional Information 1) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Summary Of Significant Accounting Policies [Line Items]
Amortization of the deferred financing costs	$ 3,856	$ 3,640	$ 3,285
Written off unamortized debt cost	600
Amortization of deferred leasing costs totaled	$ 21,300	18,500	15,200
Practical Expedient, remaining term	true
Amount of the straight-line rent receivable on the balance sheets included in rents and other receivables, net	$ 29,700	23,400
Deferred income	33,241	25,305	22,000
Amortization of deferred revenue	12,500	10,700	9,400
Equity based compensation associated with the acceleration of equity awards	3,100
Unsecured Revolving Credit Facility
Summary Of Significant Accounting Policies [Line Items]
Amortization of the deferred financing costs	3,900	3,600	3,300
Written off unamortized debt cost		5,200	200
Term Loan Maturing 2022 [Member]
Summary Of Significant Accounting Policies [Line Items]
Debt Instrument Face Amount		300,000
Term Loan Maturing 2025
Summary Of Significant Accounting Policies [Line Items]
Debt Instrument Face Amount		400,000
Restructuring Charges [Member]
Summary Of Significant Accounting Policies [Line Items]
Company recorded equity-based compensation expense net of repurchased awards and forfeits	$ 15,000	$ 13,900	$ 10,600

Summary of Significant Accoun_6

Summary of Significant Accounting Policies (Deferred Financing Costs, Net of Accumulated Amortization) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Deferred financing costs	$ 11,530	$ 9,775
Accumulated amortization	(3,859)	(1,908)
Deferred financing costs, net	7,671	7,867
Fixed debt arrangements
Deferred financing costs	14,501	12,675
Accumulated amortization	(2,944)	(1,039)
Deferred financing costs, net	$ 11,557	$ 11,636

Summary of Significant Accoun_7

Summary of Significant Accounting Policies (Deferred Leasing Costs, Net of Accumulated Amortization) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Summary of Significant Accounting Policies [Abstract]
Deferred leasing costs	$ 63,018	$ 54,868
Accumulated amortization	(25,593)	(20,956)
Deferred leasing costs, net	$ 37,425	$ 33,912

Summary of Significant Accoun_8

Summary of Significant Accounting Policies (Additional Information 2) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018USD ($)segmententity	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)
Summary Of Significant Accounting Policies [Line Items]
Aggregate allowance for doubtful accounts	$ 3,800	$ 11,500
Capital lease obligations	$ 2,700	$ 7,800
Lease financing obligation	qts:CapitalLeaseLeaseFinancingObligationsAndMortgageNotesPayable	qts:CapitalLeaseLeaseFinancingObligationsAndMortgageNotesPayable
Net book value of assets associated with leases	$ 1,800	$ 14,700
Number of operating segments | segment	1
Number of reportable segments | segment	1
Valuation allowance	$ 8,361	713	$ 393
Required minimum quarterly distribution of available cash	100
Net operating loss carry forwards related to Federal income taxes	$ 33,400
Net operating loss carry forwards related to State income taxes	66,300
Net operating loss carryforwards no expiration period	32,600
Interest expense carryforward with no expiration	8,800
Unrecognized Tax Benefits	0	0	0
Interest and penalties related to income taxes	$ 0	0	$ 0
Number of subsidiaries taxed as taxable REIT | entity	2
Valuation allowance change	$ 7,700
Statutory rate	21.00%
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
Minimum | Federal [Member]
Summary Of Significant Accounting Policies [Line Items]
Net operating loss carry forwards, expiration period	11 years
Minimum | State [Member]
Summary Of Significant Accounting Policies [Line Items]
Net operating loss carry forwards, expiration period	2 years
Maximum
Summary Of Significant Accounting Policies [Line Items]
Statutory rate		35.00%
Maximum | Federal [Member]
Summary Of Significant Accounting Policies [Line Items]
Net operating loss carry forwards, expiration period	18 years
Maximum | State [Member]
Summary Of Significant Accounting Policies [Line Items]
Net operating loss carry forwards, expiration period	20 years
Customer One | Rental Revenue | Maximum
Summary Of Significant Accounting Policies [Line Items]
Percentage of total revenue	12.80%
Two Customers [Member] | Accounts Receivable | Minimum
Summary Of Significant Accounting Policies [Line Items]
Percentage of total accounts receivable	5.00%
Two Customers [Member] | Accounts Receivable | Maximum
Summary Of Significant Accounting Policies [Line Items]
Percentage of total accounts receivable	25.00%
Both Customers [Member] | Accounts Receivable | Minimum
Summary Of Significant Accounting Policies [Line Items]
Percentage of total accounts receivable	10.00%
No Other Customers | Rental Revenue | Maximum
Summary Of Significant Accounting Policies [Line Items]
Percentage of total revenue	5.00%

Summary of Significant Accoun_9

Summary of Significant Accounting Policies (Income Taxes) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Current:
U.S. federal	$ (50)	$ 42	$ (356)
U.S. State	395	297	20
Outside United States	78	44	33
Total Current	423	383	(303)
Deferred:
U.S. federal	(3,727)	(9,734)	(8,796)
U.S. State	(64)	(427)	(877)
Total Deferred	(3,791)	(10,161)	(9,673)
Total	$ (3,368)	$ (9,778)	$ (9,976)

Summary of Significant Accou_10

Summary of Significant Accounting Policies (Summary of Temporary Differences and Carry Forwards Which Give Rise to Deferred Tax Assets and Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Deferred tax liabilities
Property and equipment	$ (3,089)	$ (4,940)	$ (15,031)
Goodwill	(1,953)	(1,396)	(1,290)
Intangibles	(11,910)	(13,606)	(24,244)
Other	(1,049)	(1,132)	(1,386)
Gross deferred tax liabilities	(18,001)	(21,074)	(41,951)
Deferred tax assets
Net operating loss carryforwards	17,610	8,888	18,035
Deferred revenue and setup charges	3,171	3,435	4,323
Leases	1	453	2,154
Other credits	287	543	492
Bad debt reserve	409	2,250	41
Interest expense carryforward IRC Sec 163(j)	2,253
Other	1,534	1,607	2,114
Gross deferred tax assets	25,265	17,176	27,159
Net deferred tax liability	7,264	(3,898)	(14,792)
Valuation allowance	(8,361)	(713)	(393)
Net deferred	$ (1,097)	$ (4,611)	$ (15,185)

Summary of Significant Accou_11

Summary of Significant Accounting Policies (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, 2018	Dec. 31, 2017	Dec. 31, 2016
Summary of Significant Accounting Policies [Abstract]
Statutory rate of applied to pre-tax income (loss)	$ (9,656)	$ (5,109)	$ (7,299)
Permanent differences, net	(97)	284	2,021
State income tax, net of federal benefit	(1,430)	(388)	(689)
Foreign income tax	78	44	33
Federal and State rate change	(146)	(3,251)
Contribution of assets to TRS		(866)
Other	41	(244)
Valuation allowance increase (decrease)	7,648	320
Total tax expense (benefit)	$ (3,368)	$ (9,778)	$ (9,976)
Effective tax rate	7.30%	65.10%	46.50%
Statutory rate	21.00%

Summary of Significant Accou_12

Summary of Significant Accounting Policies - New Accounting Pronouncements (Details) - Accounting Standards Update 201602 - Restatement Adjustment [Member] $ in Millions	Dec. 31, 2018USD ($)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Initial lease liability	$ 80
Finance lease obligation	45
Minimum
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Initial lease liability	$ 75

Acquisitions (Land Parcels) (De

Acquisitions (Land Parcels) (Details) $ in Thousands	1 Months Ended				12 Months Ended
	Oct. 31, 2018USD ($)a	Oct. 31, 2017USD ($)a	Aug. 31, 2017USD ($)a	Jul. 31, 2017USD ($)a	Dec. 31, 2018USD ($)aproperty	Dec. 31, 2017USD ($)item
Property, Plant and Equipment [Line Items]
Investment Building And Building Improvements					$ 1,917,251	$ 1,701,287
Finite Lived Intangible Assets Net					$ 95,451	109,451
Number Of Real Estate Properties | property					25
Construction in progress					$ 790,064	$ 567,819
Manassas, Virginia
Property, Plant and Equipment [Line Items]
Construction in progress					116,200
Manassas, Virginia | Assets Held For Sale
Property, Plant and Equipment [Line Items]
Construction in progress					$ 71,000
Ownership percentage					50.00%
Phoenix Arizona Land
Property, Plant and Equipment [Line Items]
Payments to Acquire Land				$ 25,000
Acres of land | a				84
Land in Ashburn, Virginia
Property, Plant and Equipment [Line Items]
Payments to Acquire Land		$ 36,000	$ 17,000
Acres of land | a		28	24
Hillsboro Oregon Land [Member]
Property, Plant and Equipment [Line Items]
Payments to Acquire Land		$ 26,000
Acres of land | a		92
Phoenix Arizona And Ashburn Virginia And Hillsboro Oregon [Member]
Property, Plant and Equipment [Line Items]
Number of acquisitions | item						4
Phoenix Arizona And Ashburn Virginia And Hillsboro Oregon [Member] | Construction in Progress
Property, Plant and Equipment [Line Items]
Fair value of land acquired						$ 163,600
Land in Atlanta Georgia
Property, Plant and Equipment [Line Items]
Payments to Acquire Land	$ 80,100
Investment Building And Building Improvements	400
Finite Lived Intangible Assets Net	$ 2,300
Acres of land | a	55
Construction in progress	$ 77,400
Land in Manassas, Virginia | Construction in Progress
Property, Plant and Equipment [Line Items]
Payments to Acquire Land					$ 37,000
Acres of land | a					118

Acquisitions (Narrative) (Detai

Acquisitions (Narrative) (Details) $ in Millions	Oct. 06, 2017USD ($)ft²MW	Dec. 16, 2016USD ($)MW	Dec. 31, 2018USD ($)	Dec. 16, 2016ft²	Dec. 16, 2016a	Jun. 06, 2016ft²aMW
Fort Worth Facility
Business Acquisition [Line Items]
Acquisition costs | $		$ 50.1
Area of facility (in square feet)				262,000	53
Capacity of the plant (in MW) | MW		50
Fort Worth Facility | Basis Of Design [Member]
Business Acquisition [Line Items]
Area of facility (in square feet)				80,000
Piscataway Facility
Business Acquisition [Line Items]
Acres of real estate property | a						38
Area of facility (in square feet)						360,000
Piscataway Facility | Raised Floor With 18 MW of Critical Power
Business Acquisition [Line Items]
Area of facility (in square feet)						89,000
Capacity of the plant (in MW) | MW						18
Piscataway Facility | Additional Raised Floor With 8 MW of Additional Critical Power
Business Acquisition [Line Items]
Area of facility (in square feet)						87,000
Capacity of the plant (in MW) | MW						8
Carpathia Hosting, Inc.
Business Acquisition [Line Items]
Capital Lease Obligations Incurred | $			$ 0.3
Vault Campus In Dulles Virginia [Member] [Member]
Business Acquisition [Line Items]
Area of facility (in square feet)	87,000
Capital Lease Obligations Incurred | $	$ 17.8
Payments to Acquire Land | $	34.1
Net purchase price | $	$ 16.3
Vault Campus In Dulles Virginia [Member] [Member] | Raised Floor With Thirteen Mw Of Critical Power [Member]
Business Acquisition [Line Items]
Area of facility (in square feet)	31,000
Capacity of the plant (in MW) | MW	13

Acquisitions (Allocation of the

Acquisitions (Allocation of the Fair Value of Assets Acquired and Liabilities Assumed As Of The Acquisition Date (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2018	Jun. 30, 2017	Dec. 31, 2016	Jun. 30, 2016
Business Acquisition [Line Items]
Land	$ 9,363			$ 7,602
Buildings, improvements and equipment	14,341	$ 445		80,975
Construction in Progress	103,334	114,283		62,884
Other assets				309
Deferred income taxes				6,045
Goodwill	173,843	$ 173,843
Fort Worth Facility
Business Acquisition [Line Items]
Land	136
Buildings, improvements and equipment	610
Construction in Progress	48,987
Acquired intangibles	237
Deferred costs	23
Other assets	7
Net working capital	86
Total identifiable assets acquired	50,086
Fort Worth Facility | Adjustment
Business Acquisition [Line Items]
Construction in Progress	3
Acquired intangibles	(3)
Piscataway Facility
Business Acquisition [Line Items]
Land			$ 7,466
Buildings, improvements and equipment			80,366
Construction in Progress			13,900
Acquired intangibles			19,581
Deferred costs			4,390
Other assets			106
Total identifiable assets acquired			125,809
Acquired below market lease			809
Net working capital			2,019
Total liabilities assumed			2,828
Net identifiable assets acquired			$ 122,981
Measurement period adjustment	0
Piscataway Facility | Adjustment
Business Acquisition [Line Items]
Land	26
Buildings, improvements and equipment	1,996
Acquired intangibles	(2,087)
Deferred costs	306
Total identifiable assets acquired	241
Acquired below market lease	241
Total liabilities assumed	$ 241
Preliminary Allocation Reported | Fort Worth Facility
Business Acquisition [Line Items]
Land				136
Buildings, improvements and equipment				610
Construction in Progress				48,984
Acquired intangibles				240
Deferred costs				23
Other assets				7
Net working capital				86
Total identifiable assets acquired				$ 50,086
Preliminary Allocation Reported | Piscataway Facility
Business Acquisition [Line Items]
Land					$ 7,440
Buildings, improvements and equipment					78,370
Construction in Progress					13,900
Acquired intangibles					21,668
Deferred costs					4,084
Other assets					106
Total identifiable assets acquired					125,568
Acquired below market lease					568
Net working capital					2,019
Total liabilities assumed					2,587
Net identifiable assets acquired					$ 122,981

Acquired Intangibles Assets a_3

Acquired Intangibles Assets and Liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Finite-lived intangible assets
Gross Carrying Value	$ 161,168	$ 158,867
Accumulated Amortization	(65,717)	(49,416)
Net Carrying Value	95,451	109,451
Acquired Intangible Liabilities
Acquired intangible liabilities	17,009	17,009
Accumulated Amortization	(5,017)	(3,755)
New Carrying Value	$ 11,992	$ 13,254
Customer Relationships
Finite-lived intangible assets
Useful Lives	12 years	12 years
Gross Carrying Value	$ 95,705	$ 95,705
Accumulated Amortization	(28,461)	(20,512)
Net Carrying Value	67,244	75,193
In Place Leases
Finite-lived intangible assets
Gross Carrying Value	32,066	32,066
Accumulated Amortization	(17,670)	(12,987)
Net Carrying Value	$ 14,396	$ 19,079
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	(3,639)	(2,830)
Net Carrying Value	$ 10,108	$ 10,917
Platform Intangible
Finite-lived intangible assets
Useful Lives	3 years	3 years
Gross Carrying Value	$ 9,600	$ 9,600
Accumulated Amortization	$ (9,600)	(8,133)
Net Carrying Value		1,467
Below Market Lease As Lessee [Member]
Finite-lived intangible assets
Useful Lives	46 years
Acquired below market leases - as Lessor
Gross Carrying Value	$ 2,301
Net Carrying Value	2,301
Above Market Lease As Lessor [Member]
Acquired above market leases - as Lessee
Gross Carrying Value	4,649	4,649
Accumulated Amortization	(3,247)	(2,328)
Net Carrying Value	$ 1,402	$ 2,321
Above Market Lease As Lessor [Member] | Minimum
Finite-lived intangible assets
Useful Lives	6 months	6 months
Above Market Lease As Lessor [Member] | Maximum
Finite-lived intangible assets
Useful Lives	8 years	8 years
Below Market Lease As Lessor [Member]
Acquired below market leases - as Lessor
Gross Carrying Value	$ 809	$ 809
Accumulated Amortization	(611)	(375)
Net Carrying Value	$ 198	$ 434
Below Market Lease As Lessor [Member] | Minimum
Acquired below market leases - as Lessor
Useful Lives	3 years	3 years
Below Market Lease As Lessor [Member] | Maximum
Acquired below market leases - as Lessor
Useful Lives	4 years	4 years
Above Market Lease As Lessee [Member]
Acquired above market leases - as Lessee
Gross Carrying Value	$ 2,453	$ 2,453
Accumulated Amortization	(767)	(550)
Net Carrying Value	$ 1,686	$ 1,903
Above Market Lease As Lessee [Member] | Minimum
Finite-lived intangible assets
Useful Lives	11 years	11 years
Above Market Lease As Lessee [Member] | Maximum
Finite-lived intangible assets
Useful Lives	12 years	12 years
Tradenames
Finite-lived intangible assets
Useful Lives	3 years	3 years
Gross Carrying Value	$ 3,100	$ 3,100
Accumulated Amortization	$ (3,100)	(2,626)
Net Carrying Value		$ 474

Acquired Intangibles Assets a_4

Acquired Intangibles Assets and Liabilities - Amortization (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Acquired Intangible Assets and Liabilities
Amortization of acquired above and below-market leases, net	$ 465	$ 865	$ 659
Amortization of all other identified intangible assets	15,000	18,200	$ 19,000
Estimated amortization of all other identified intangible assets
Net Carrying Value	95,451	$ 109,451
Acquired favorable and unfavorable leases
Estimated amortization of acquired favorable and unfavorable leases Rental Revenue
2,019	479
2,020	647
2,021	46
2,022	17
2,023	17
Thereafter	(1,446)
Total	1,205
Estimated amortization of acquired favorable and unfavorable leases Rental Expense
2,019	(166)
2,020	(166)
2,021	(166)
2,022	(166)
2,023	(166)
Total	615
All other identified intangible assets
Estimated amortization of all other identified intangible assets
2,019	11,965
2,020	11,379
2,021	10,137
2,022	9,910
2,023	9,910
Thereafter	28,339
Net Carrying Value	$ 81,640

Real Estate Assets and Constr_3

Real Estate Assets and Construction in Progress (Summary of Properties Owned or Leased by the Company) (Details) $ in Thousands	Dec. 31, 2018USD ($)property	Dec. 31, 2017USD ($)property
Real Estate Properties [Line Items]
Land	$ 105,541	$ 88,216
Buildings, Improvements and Equipment	1,917,251	1,701,287
Construction in progress	790,064	567,819
Total cost	2,812,856	2,357,322
Manassas, Virginia
Real Estate Properties [Line Items]
Construction in progress	116,200
Manassas, Virginia | Assets Held For Sale
Real Estate Properties [Line Items]
Construction in progress	71,000
Owned Properties | Atlanta, Georgia (Atlanta-Metro)
Real Estate Properties [Line Items]
Land	20,416	20,416
Buildings, Improvements and Equipment	493,446	452,836
Construction in progress	88,253	28,614
Total cost	602,115	501,866
Owned Properties | Irving Texas
Real Estate Properties [Line Items]
Land	8,606	8,606
Buildings, Improvements and Equipment	345,615	276,894
Construction in progress	99,445	86,320
Total cost	453,666	371,820
Owned Properties | Richmond, Virginia
Real Estate Properties [Line Items]
Land	2,180	2,180
Buildings, Improvements and Equipment	253,098	254,603
Construction in progress	67,932	61,888
Total cost	323,210	318,671
Owned Properties | Chicago, Illinois
Real Estate Properties [Line Items]
Land	9,400	9,400
Buildings, Improvements and Equipment	130,150	81,463
Construction in progress	133,095	135,479
Total cost	272,645	226,342
Owned Properties | Ashburn, Virginia
Real Estate Properties [Line Items]
Land	17,325
Buildings, Improvements and Equipment	63,245
Construction in progress	184,951	106,952
Total cost	265,521	106,952
Owned Properties | Suwanee, Georgia (Atlanta-Suwanee)
Real Estate Properties [Line Items]
Land	3,521	3,521
Buildings, Improvements and Equipment	166,298	165,915
Construction in progress	3,188	3,620
Total cost	173,007	173,056
Owned Properties | Piscataway New Jersey
Real Estate Properties [Line Items]
Land	7,466	7,466
Buildings, Improvements and Equipment	97,806	83,251
Construction in progress	33,472	37,807
Total cost	138,744	128,524
Owned Properties | Manassas, Virginia
Real Estate Properties [Line Items]
Construction in progress	45,194
Total cost	45,194
Owned Properties | Manassas, Virginia | Assets Held For Sale
Real Estate Properties [Line Items]
Construction in progress	71,000
Owned Properties | Santa Clara, California
Real Estate Properties [Line Items]
Buildings, Improvements and Equipment	98,548	100,028
Construction in progress	7,600	6,989
Total cost	106,148	107,017
Owned Properties | Dulles, Virginia
Real Estate Properties [Line Items]
Land	3,154	3,154
Buildings, Improvements and Equipment	72,435	76,239
Construction in progress	3,852	3,565
Total cost	79,441	82,958
Owned Properties | Fort Worth, Texas
Real Estate Properties [Line Items]
Land	9,079	9,079
Buildings, Improvements and Equipment	18,623	17,894
Construction in progress	43,715	33,774
Total cost	71,417	60,747
Owned Properties | Sacramento, California
Real Estate Properties [Line Items]
Land	1,481	1,481
Buildings, Improvements and Equipment	64,874	64,251
Construction in progress	92	58
Total cost	66,447	65,790
Owned Properties | Princeton, New Jersey
Real Estate Properties [Line Items]
Land	20,700	20,700
Buildings, Improvements and Equipment	34,046	32,948
Construction in progress	431	451
Total cost	55,177	54,099
Owned Properties | Hillsboro, Oregon
Real Estate Properties [Line Items]
Construction in progress	39,835	29,278
Total cost	39,835	29,278
Owned Properties | Phoenix, Arizona
Real Estate Properties [Line Items]
Construction in progress	29,562	27,402
Total cost	29,562	27,402
Owned Properties | Other
Real Estate Properties [Line Items]
Land	2,213	2,213
Buildings, Improvements and Equipment	35,720	35,505
Construction in progress	113	88
Total cost	$ 38,046	$ 37,806
Leased Properties
Real Estate Properties [Line Items]
Number of facilities leased | property	10	11
Leased Properties | Owned Properties
Real Estate Properties [Line Items]
Buildings, Improvements and Equipment	$ 43,347	$ 59,460
Construction in progress	9,334	5,534
Total cost	$ 52,681	$ 64,994

Debt (Outstanding Debt Includin

Debt (Outstanding Debt Including Capital Leases) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Weighted average coupon interest rate	3.89%
Total debt and lease obligations	$ 1,356,674	$ 1,241,565
Less net debt issuance costs	11,557	11,636
Total outstanding debt, net	$ 1,345,117	1,229,929
Revolving Credit Facility
Debt Instrument [Line Items]
Weighted average coupon interest rate	3.75%
Maturity date	Dec. 17, 2022
Outstanding debt	$ 252,000	131,000
Term Loan
Debt Instrument [Line Items]
Outstanding debt	$ 700,000
Term Loan I [Member]
Debt Instrument [Line Items]
Weighted average coupon interest rate	3.44%
Maturity date	Dec. 17, 2023
Outstanding debt	$ 350,000	350,000
Term Loan II [Member]
Debt Instrument [Line Items]
Weighted average coupon interest rate	3.47%
Maturity date	Apr. 27, 2024
Outstanding debt	$ 350,000	350,000
Lenexa Mortgage
Debt Instrument [Line Items]
Weighted average coupon interest rate	4.10%
Maturity date	May 1, 2022
Outstanding debt	$ 1,801	1,866
Capital Lease and Lease Financing Obligations [Member]
Debt Instrument [Line Items]
Weighted average coupon interest rate	4.34%
Maturity date description	2019 - 2038
Capital Lease and Lease Financing Obligations	$ 2,873	8,699
Operating Partnership Quality Tech LP 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

Debt (Unsecured Credit Facility

Debt (Unsecured Credit Facility Narrative) (Details) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Nov. 30, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 20, 2018	Apr. 05, 2017
Debt Instrument [Line Items]
Reduction of price, percentage	20.00%
Interest Rate Swap
Debt Instrument [Line Items]
Notional amount of derivative				$ 400,000	$ 400,000
Term Loan
Debt Instrument [Line Items]
Outstanding debt		$ 700,000
Term Loan | Interest Rate Swap
Debt Instrument [Line Items]
Outstanding debt		200,000		400,000
Notional amount of derivative		200,000
Term Loan Maturing December 17,2021 | Interest Rate Swap
Debt Instrument [Line Items]
Notional amount of derivative				200,000	200,000
Term Loan Maturing April 27, 2022 | Interest Rate Swap
Debt Instrument [Line Items]
Notional amount of derivative				$ 200,000	$ 200,000
Term Loan Maturing April 27 2024 | Interest Rate Swap
Debt Instrument [Line Items]
Notional amount of derivative		100,000
Term Loan Maturing December 17 2023 | Interest Rate Swap
Debt Instrument [Line Items]
Notional amount of derivative		$ 100,000
Revolving Credit Facility
Debt Instrument [Line Items]
Maturity date		Dec. 17, 2022
Outstanding debt		$ 252,000	$ 131,000
Letter of Credit [Member]
Debt Instrument [Line Items]
Letter of credit outstanding		$ 4,100
Line of credit facility weighted average interest rate outstanding percentage		3.53%
Unsecured Credit Facility
Debt Instrument [Line Items]
Line of credit facility accordion feature		$ 500,000
Minimum | Term Loan | LIBOR
Debt Instrument [Line Items]
Debt instrument spread on variable interest rate		1.30%
Minimum | Term Loan | Base Rate
Debt Instrument [Line Items]
Debt instrument spread on variable interest rate		0.30%
Minimum | Revolving Credit Facility | LIBOR
Debt Instrument [Line Items]
Debt instrument spread on variable interest rate		1.35%
Minimum | Revolving Credit Facility | Base Rate
Debt Instrument [Line Items]
Debt instrument spread on variable interest rate		0.35%
Maximum | Term Loan | LIBOR
Debt Instrument [Line Items]
Debt instrument spread on variable interest rate		1.90%
Maximum | Term Loan | Base Rate
Debt Instrument [Line Items]
Debt instrument spread on variable interest rate		0.90%
Maximum | Revolving Credit Facility | LIBOR
Debt Instrument [Line Items]
Debt instrument spread on variable interest rate		1.95%
Maximum | Revolving Credit Facility | Base Rate
Debt Instrument [Line Items]
Debt instrument spread on variable interest rate		0.95%
Maximum | Unsecured Credit Facility
Debt Instrument [Line Items]
Credit facility maximum borrowing capacity		$ 200,000
Unsecured Credit Facility
Debt Instrument [Line Items]
Credit facility maximum borrowing capacity			1,520,000
Additional contingent borrowing capacity, maximum			$ 2,020,000
Outstanding debt		$ 952,000
Unsecured Credit Facility | Term Loan Maturing December 17,2021
Debt Instrument [Line Items]
Maturity date	Dec. 17, 2022
Unsecured Credit Facility | Term Loan Maturing April 27 2024
Debt Instrument [Line Items]
Credit facility maximum borrowing capacity	$ 350,000
Maturity date	Apr. 27, 2024
Unsecured Credit Facility | Term Loan Maturing December 17 2023
Debt Instrument [Line Items]
Credit facility maximum borrowing capacity	$ 350,000
Maturity date	Dec. 17, 2023
Unsecured Credit Facility | Term Loan Maturing December 17, 2022
Debt Instrument [Line Items]
Credit facility maximum borrowing capacity	$ 820,000
Unsecured Credit Facility | Revolving Credit Facility
Debt Instrument [Line Items]
Debt extension period			1 year

Debt (Senior Notes) (Details)

Debt (Senior Notes) (Details) - USD ($) $ in Thousands	Nov. 08, 2017	Dec. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Debt issuance costs, net		$ 7,671	$ 7,867
Operating Partnership And QTS Finance Corporation
Debt Instrument [Line Items]
Interest rate	5.875%
Operating Partnership Quality Tech LP And QTS Finance Corporation
Debt Instrument [Line Items]
Aggregate principal amount	$ 400,000
Interest rate	4.75%
Senior notes due	2,025
Debt issuance costs, net		5,200
Percentage of issued price equal to face value	100.00%
Term Loan
Debt Instrument [Line Items]
Debt issuance costs, net		$ 6,300
Term Loan Maturing 2022 [Member]
Debt Instrument [Line Items]
Aggregate principal amount			$ 300,000
Interest rate			5.875%

Debt (Annual Remaining Principa

Debt (Annual Remaining Principal Payment) (Details) $ in Thousands	Dec. 31, 2018USD ($)
Debt [Abstract]
2,019	$ 62
2,020	71
2,021	74
2,022	253,594
2,023	350,000
Thereafter	750,000
Total	$ 1,353,801

Debt (Lease Narrative) (Details

Debt (Lease Narrative) (Details) - Carpathia Hosting, Inc.	12 Months Ended
	Dec. 31, 2018USD ($)
Capital Leased Assets [Line Items]
Capital lease, lease financing obligations and mortgage notes payable	$ 2,700,000
Capital lease and lease financing obligations assumed	300,000
Number of expired capital lease arrangements	2
Minimum
Capital Leased Assets [Line Items]
Monthly lease payment	200,000
Maximum
Capital Leased Assets [Line Items]
Monthly lease payment	$ 500,000

Debt (Future Payment Obligation

Debt (Future Payment Obligations) (Details) $ in Thousands	Dec. 31, 2018USD ($)
Debt [Abstract]
2,019	$ 994
2,020	151
2,021	48
2,022	44
2,023	49
Thereafter	1,587
Total lease obligations	$ 2,873

Interest Rate Swaps (Details)

Interest Rate Swaps (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 20, 2018	Apr. 05, 2017
Derivative [Line Items]
Increase in fair value of interest rate swaps	$ 895	$ 1,449
Term Loan
Derivative [Line Items]
Outstanding debt	700,000
Interest Rate Swap
Derivative [Line Items]
Derivative instruments, notional amount				$ 400,000	$ 400,000
Ineffectiveness recognized	0	0	$ 0
Interest Rate Swap | Term Loan
Derivative [Line Items]
Derivative instruments, notional amount	200,000
Outstanding debt	$ 200,000			400,000
Interest Rate Swap | Term Loan Maturing April 27, 2022
Derivative [Line Items]
Derivative instruments, notional amount				200,000	200,000
Weighted average effective fixed interest rate	3.90%
Interest Rate Swap | Term Loan Maturing December 17,2021
Derivative [Line Items]
Derivative instruments, notional amount				$ 200,000	$ 200,000
Weighted average effective fixed interest rate					3.30%
Average variable interest rate	1.30%
Interest Rate Swap | Term Loan Maturing December 17 2023
Derivative [Line Items]
Derivative instruments, notional amount	$ 100,000
Interest Rate Swap | Term Loan Maturing April 27 2024
Derivative [Line Items]
Derivative instruments, notional amount	100,000
Cash flow hedging | Interest Rate Swap
Derivative [Line Items]
Derivative instruments, notional amount	1,000,000	400,000
Derivative Asset, fair Value	5,300
Derivative Liability, fair Value	3,000
Fair value	$ 2,343	$ 1,449

Interest Rate Swaps - Interest

Interest Rate Swaps - Interest rate derivatives and their fair values (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 20, 2018	Apr. 05, 2017
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Reclassification of other comprehensive income to interest expense		$ (110)	$ 0	$ 0
Forecast
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Reclassification of other comprehensive income to interest expense	$ 2,100
Interest Rate Swap
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional amount of derivative					$ 400,000	$ 400,000
Interest Rate Swap | Cash flow hedging
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional amount of derivative		1,000,000	400,000
Fair value		2,343	1,449
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		$ 331	100
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		$ 1,318	401
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		$ 990	298
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		$ 667	158
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		$ 1,341	337
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		$ 666	$ 155
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
Fixed Rate Per annum		2.617%
Expiration Date		Dec. 17, 2023
Fair value		$ (782)
Swap instrument two matures on December 17, 2023
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Notional amount of derivative		$ 200,000
Fixed Rate Per annum		2.636%
Expiration Date		Dec. 17, 2023
Fair value		$ (722)
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
Fixed Rate Per annum		2.621%
Expiration Date		Apr. 27, 2024
Fair value		$ (818)
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
Fixed Rate Per annum		2.642%
Expiration Date		Apr. 27, 2024
Fair value		$ (648)

Restructuring (Details)

Restructuring (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018USD ($)
Restructuring Cost and Reserve [Line Items]
Restructuring expense	$ 37,943
Severance
Restructuring Cost and Reserve [Line Items]
Restructuring expense	6,910
Equity Based Compensation and Professional Fees
Restructuring Cost and Reserve [Line Items]
Restructuring expense	7,740
Product Related and Other
Restructuring Cost and Reserve [Line Items]
Restructuring expense	23,293
Accounts Payable and Accrued Liabilities | Severance
Restructuring Cost and Reserve [Line Items]
Outstanding liability	400
Accounts Payable and Accrued Liabilities | Product Related and Other
Restructuring Cost and Reserve [Line Items]
Outstanding liability	$ 2,300

Partners' Capital, Equity and_3

Partners' Capital, Equity and Incentive Compensation Plans (Narrative) (Details) $ / shares in Units, $ in Thousands	May 04, 2017item$ / shares	Dec. 31, 2018USD ($)Partnershipitemshares	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)	May 31, 2015shares
Partners Capital And Distributions [Line Items]
Number of classes of partnership units outstanding | Partnership		4
Equity based compensation expense unrecognized | $		$ 13,700
Equity based compensation expense vesting period		1 year 4 months 24 days
Equity based compensation awards intrinsic value | $		$ 25,500
Common stock issuance proceeds, net of costs | $			$ 107,549	$ 275,663
QTS Realty Trust, Inc. Employee Stock Purchase Plan
Partners Capital And Distributions [Line Items]
Shares reserved for purchase under plan | shares		250,000
2017 Plan
Partners Capital And Distributions [Line Items]
Minimum period of service	30 days
Minimum hours per week of service | item	30
Purchase period per year | item	4
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]
Discount rate of purchase price of common stock	10.00%
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 share | $ / 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 share | $ / shares	$ 1,000
Restricted Class A Common Stock
Partners Capital And Distributions [Line Items]
Nonvested awards outstanding | shares		400,000
Options to purchase Class A common stock
Partners Capital And Distributions [Line Items]
Nonvested awards outstanding | shares		800,000
2013 Equity Incentive Plan | Class A Common Stock
Partners Capital And Distributions [Line Items]
Authorized shares to be issued under the plan | shares		1,750,000			4,750,000
Qualitytech, LP
Partners Capital And Distributions [Line Items]
Common stock issuance proceeds, net of costs | $			$ 107,549	$ 275,663

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, 2018	Dec. 31, 2017	Dec. 31, 2016
2013 Equity Incentive Plan | Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Beginning balance, Options Outstanding (in shares)	1,369,270	1,058,297	867,882
Options, Granted (in shares)	674,081	468,875	229,693
Options, Exercised (in shares)	(6,188)	(155,902)	(29,543)
Options, Cancelled/Expired (in shares)		(2,000)	(9,735)
Ending balance, Options Outstanding (in shares)	2,037,163	1,369,270	1,058,297
Beginning balance, Weighted average exercise price options outstanding	$ 38.18	$ 31.72	$ 27.80
Weighted average exercise price options outstanding, Granted	34.05	50.66	45.78
Weighted average exercise price options outstanding, Exercised	21.50	31.89	25.70
Weighted average exercise price options outstanding, Cancelled/Expired		37.69	32.14
Ending balance, Weighted average exercise price options outstanding	36.86	38.18	31.72
Beginning balance, weighted average fair value, options	7.80	6.51	5.56
Weighted average fair value, granted, options	5.63	10.32	9.91
Weighted average fair value, vested, options	3.68	6.60	4.96
Weighted average fair value, cancelled/expired, options		8.77	6.95
Ending balance, weighted average fair value, options	$ 7.10	$ 7.80	$ 6.51
2013 Equity Incentive Plan | Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Beginning balance, Number of units (in shares)	381,864	414,691	394,908
Number of units, Granted (in shares)	348,152	228,576	237,563
Number of units, Exercised	(224,660)	(163,048)	(122,136)
Number of units, Cancelled/Expired (in shares)	(85,047)	(98,355)	(95,644)
Ending balance, Number of units (in shares)	420,309	381,864	414,691
Beginning balance, Weighted average exercise price units	$ 46.37	$ 40.67	$ 33.82
Weighted average exercise price units, Granted	35.27	49.86	45.53
Weighted average exercise price units, Exercised	46.23	40.63	33.26
Weighted average exercise price units, Cancelled/Expired	43.50	39.97	33.92
Ending balance, Weighted average exercise price units	$ 37.83	$ 46.37	$ 40.67
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)	568,040	1,134,811	1,292,899
Number of units, Exercised	(465,761)	(566,771)	(158,088)
Ending balance, Number of units (in shares)	102,279	568,040	1,134,811
Beginning balance, Weighted average exercise price units	$ 23.52	$ 24.06	$ 23.76
Weighted average exercise price units, Exercised	23.40	24.60	21.56
Ending balance, Weighted average exercise price units	24.05	23.52	24.06
Beginning balance, Weighted average fair value	5	3.62	3.68
Weighted average fair value, Exercised	4.76	2.24	4.18
Ending balance, Weighted average fair value	$ 5.67	$ 5	$ 3.62
Class RS Units | 2010 Equity Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Beginning balance, Number of units (in shares)			39,875
Number of units, Released from restriction (in shares)			(39,875)
Beginning balance, Weighted average exercise price units			$ 22.18
Weighted average exercise price units, Released from restriction			$ 22.18

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, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility		28.00%
Expected dividend yield	4.82%	3.08%	3.14%
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value of restricted stock granted	$ 34.03	$ 48.63	$ 45.78
Fair value of options granted	$ 5.55	$ 10.11	$ 9.57
Expected term (years)	5 years 6 months	5 years 6 months	5 years 6 months
Expected volatility	28.00%	28.00%	30.70%
Expected dividend yield			3.14%
Expected risk-free interest rates	2.69%	2.12%	1.42%
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value of restricted stock granted	$ 54.01	$ 51.88
Fair value of options granted	$ 5.64	$ 10.36	$ 9.97
Expected term (years)	6 years	5 years 10 months 24 days	5 years 10 months 24 days
Expected volatility			31.30%
Expected risk-free interest rates	2.73%	2.18%	1.48%

Partners' Capital, Equity and_6

Partners' Capital, Equity and Incentive Compensation Plans (Summary of Information About Awards Outstanding) (Details)	12 Months Ended
	Dec. 31, 2018$ / sharesshares
QualityTech LP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards Outstanding	102,279
QTS Realty Trust, Inc Awards Outstanding
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards Outstanding	2,457,472
QTS Realty Trust, Inc Awards Outstanding | Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards Outstanding	420,309
Remaining term of awards	1 year 8 months 12 days
QTS Realty Trust, Inc Awards Outstanding | 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	2,037,163
Remaining term of awards	1 year 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	102,279

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. 22, 2019	Jan. 15, 2019	Jan. 08, 2019	Jun. 25, 2018	Mar. 15, 2018	Apr. 14, 2018	Jan. 14, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Oct. 14, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Record Date												Sep. 22, 2017	Jun. 16, 2017	Mar. 16, 2017	Dec. 16, 2016
Payment Date												Oct. 5, 2017	Jul. 6, 2017	Apr. 5, 2017	Jan. 5, 2017
Per Share and Per Unit Rate												$ 0.39	$ 0.39	$ 0.39	$ 0.36			$ 1.53
Dividend/Distribution Amount												$ 22,200	$ 21,600	$ 21,400	$ 19,700			$ 84,900
Preferred stock, issued					4,280,000
Preferred stock issuance proceeds, net of costs																	$ 407,477
Series A Redeemable Perpetual Preferred [Member]
Record Date								Sep. 28, 2018	Jun. 29, 2018	Apr. 5, 2018
Payment Date								Oct. 15, 2018	Jul. 16, 2018	Apr. 16, 2018
Per Share and Per Unit Rate								$ 0.45	$ 0.45	$ 0.15
Dividend/Distribution Amount								$ 1,900	$ 1,900	$ 600
Preferred stock dividends per share cash paid						$ 0.14844
Dividend rate (as a percent)					7.125%												7.125%
Preferred stock, issued					4,280,000			4,280,000				0					4,280,000	0
Preferred stock issuance proceeds, net of costs					$ 103,200
Preferred stock redemption price per share								$ 25									$ 25
Threshold period of redemption of preferred stock																	120 days
Ownership interest								50.00%									50.00%
Convertible preferred stock par value								$ 0.01									$ 0.01
Preferred stock, liquidation preference					$ 25			25				$ 25					25	$ 25
Share cap price								$ 1.46929									$ 1.46929
Series B Convertible Preferred Stock [Member]
Record Date								Sep. 30, 2018
Payment Date								Oct. 15, 2018
Per Share and Per Unit Rate								$ 1.99
Dividend/Distribution Amount								$ 6,300									$ 6,300
Preferred stock dividends per share cash paid																$ 1.9861111
Dividend rate (as a percent)				6.50%													6.50%
Preferred stock, issued				3,162,500				3,162,500				0					3,162,500	0
Preferred stock issuance proceeds, net of costs				$ 304,000
Number of shares of the company's common stock issued upon initial conversion (in shares)								2.1264									2.1264
Minimum percentage of closing sale price of common stock under preferred stock conversion (as a percent)																	150.00%
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
Preferred stock, liquidation preference				$ 100				$ 100				$ 100					$ 100	$ 100
Share cap price								$ 5.1020									$ 5.1020
Subsequent Event
Record Date	Mar. 20, 2019
Payment Date	Apr. 4, 2019
Subsequent Event | Series A Redeemable Perpetual Preferred [Member]
Payment Date		Jan. 15, 2019
Per Share and Per Unit Rate		$ 0.45
Subsequent Event | Series B Convertible Preferred Stock [Member]
Payment Date		Jan. 15, 2019
Per Share and Per Unit Rate							$ 1.63
Subsequent Event | Series B Preferred Stock
Record Date	Mar. 31, 2019
Payment Date	Apr. 15, 2019
Underwriter's Option | Series A Redeemable Perpetual Preferred [Member]
Preferred stock, issued					280,000
Underwriter's Option | Series B Convertible Preferred Stock [Member]
Preferred stock, issued				412,500
At Market | Class A Common Stock
Maximum value of stock which may be issued															$ 300,000
Net proceeds from stock offering (in shares)																	0
Common stock
Record Date								Sep. 20, 2018	Jun. 20, 2018	Mar. 22, 2018	Dec. 5, 2017
Payment Date								Oct. 4, 2018	Jul. 6, 2018	Apr. 5, 2018	Jan. 5, 2018
Per Share and Per Unit Rate								$ 0.41	$ 0.41	$ 0.41	$ 0.39						$ 1.62
Dividend/Distribution Amount								$ 23,700	$ 23,700	$ 23,700	$ 22,200						$ 93,300
Net proceeds from stock offering (in shares)																		2,036,000	6,325,000
Common stock | Series A Redeemable Perpetual Preferred [Member]
Per Share and Per Unit Rate																	$ 1.04
Dividend/Distribution Amount																	$ 4,400
Common stock | Subsequent Event
Payment Date			Jan. 8, 2019
Per Share and Per Unit Rate			$ 0.41
Preferred stock | Series A Redeemable Perpetual Preferred [Member]
Net proceeds from stock offering (in shares)																	4,280,000

Related Party Transactions (Sum

Related Party Transactions (Summary of Related Party Transactions) (Details) - Affiliated Entity - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Related Party Transaction [Line Items]
Tax, utility, insurance and other reimbursement	$ 724	$ 796	$ 878
Rent expense	1,014	1,014	1,014
Capital assets acquired	464	561	323
Total	$ 2,202	$ 2,371	$ 2,215

Employee Benefit Plan (Narrativ

Employee Benefit Plan (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	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	$ 2.6	$ 2.5
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, 2018	Oct. 13, 2013
Stock conversion ratio	1
Qualitytech, LP
Quality Tech LP ownership percentage in operating partnership	11.50%	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, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Earnings per Share [Abstract]
Net income (loss)	$ 6,402	$ (6,892)	$ (6,433)	$ (252)	$ (16,113)	$ 7,394	$ 4,608	$ 5,568	$ (7,175)	$ 1,457	$ 24,685
Loss (Income) attributable to noncontrolling interests									2,715	(175)	(3,160)
Preferred stock dividends									(16,666)
Earnings attributable to participating securities									(947)	(593)	3,160
Net income (loss) available to common stockholders after allocation of participating securities									$ (22,073)	$ 689	$ 24,685
Weighted average shares outstanding-basic									50,432,590	48,380,964	46,205,937
Effect of Class A partnership units										6,696,000	6,783,000
Effect of Class O units and options to purchase Class A common stock on an "as if" converted basis										779,000	973,000
Weighted average shares outstanding-diluted									50,432,590	55,855,683	53,962,234
Basic net income (loss) per share	$ (0.02)	$ (0.25)	$ (0.16)	$ (0.02)	$ (0.29)	$ 0.13	$ 0.08	$ 0.10	$ (0.44)	$ 0.01	$ 0.47
Diluted net income (loss) per share	$ (0.02)	$ (0.25)	$ (0.16)	$ (0.02)	$ (0.29)	$ 0.13	$ 0.08	$ 0.10	$ (0.44)	$ 0.01	$ 0.46

Earnings per share of QTS Rea_4

Earnings per share of QTS Realty Trust, Inc.(Narrative) (Details) shares in Millions	12 Months Ended
	Dec. 31, 2018shares
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	6.7
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	0.4
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	3.5

Operating Leases, as Lessee (Na

Operating Leases, as Lessee (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Operating Leased Assets [Line Items]
Rent expense under operating leases	$ 15.4	$ 17.9	$ 20.1
Capitalized rent	$ 0	$ 0	$ 0.1
Santa Clara [Member]
Operating Leased Assets [Line Items]
Sublease expiration period	2052-10

Operating Leases, as Lessee (Fu

Operating Leases, as Lessee (Future Non-cancellable Minimum Rental Payments Required Under Operating Leases and/or Licenses) (Details) $ in Thousands	Dec. 31, 2018USD ($)
Leases [Abstract]
2,019	$ 14,778
2,020	11,128
2,021	11,008
2,022	10,161
2,023	10,250
Thereafter	57,221
Total	$ 114,546

Contracts with Customers (Detai

Contracts with Customers (Details) $ in Thousands	Dec. 31, 2018USD ($)
Contracts with Customers [Abstract]
2,019	$ 355,440
2,020	291,162
2,021	232,905
2,022	152,069
2,023	84,368
Thereafter	112,889
Total	$ 1,228,833

Fair Value of Financial Instr_2

Fair Value of Financial Instruments (Narrative) (Details) $ in Millions	Dec. 31, 2018USD ($)
Senior Notes. | Fair Value Measurements, Level 2
Fair Value Of Financial Instruments [Line Items]
Fair value of loan based on current market rates	$ 374

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, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Effect of Fourth Quarter Events [Line Items]
Revenues	$ 112,337	$ 112,213	$ 112,277	$ 113,697	$ 118,911	$ 113,767	$ 107,868	$ 105,964	$ 450,524	$ 446,510	$ 402,363
Operating income (loss)	12,876	(1,552)	1,882	5,455	7,553	12,833	10,826	10,915	18,661	42,127	38,057
Net income (loss)	6,402	(6,892)	(6,433)	(252)	(16,113)	7,394	4,608	5,568	(7,175)	1,457	24,685
Net income (loss) attributable to QTS Realty Trust, Inc.	6,476	(5,282)	(5,431)	(223)	(14,142)	6,507	4,040	4,877	(4,460)	1,282	21,525
Net income (loss) attributable to common stockholders	$ (569)	$ (12,327)	$ (7,679)	$ (551)	$ (14,142)	$ 6,507	$ 4,040	$ 4,877	$ (21,126)	$ 1,282	$ 21,525
Basic (in dollars per share)	$ (0.02)	$ (0.25)	$ (0.16)	$ (0.02)	$ (0.29)	$ 0.13	$ 0.08	$ 0.10	$ (0.44)	$ 0.01	$ 0.47
Diluted (in dollars per share)	$ (0.02)	$ (0.25)	$ (0.16)	$ (0.02)	$ (0.29)	$ 0.13	$ 0.08	$ 0.10	$ (0.44)	$ 0.01	$ 0.46
Qualitytech, LP
Effect of Fourth Quarter Events [Line Items]
Revenues	$ 112,337	$ 112,213	$ 112,277	$ 113,697	$ 118,911	$ 113,767	$ 107,868	$ 105,964	$ 450,524	$ 446,510	$ 402,363
Operating income (loss)	12,876	(1,552)	1,882	5,455	7,553	12,833	10,826	10,915	18,661	42,127	38,057
Net income (loss)	6,402	(6,892)	(6,433)	(252)	(16,113)	7,394	4,608	5,568	(7,175)	1,457	24,685
Net income (loss) attributable to common stockholders	$ (643)	$ (13,937)	$ (8,681)	$ (580)	$ (16,113)	$ 7,394	$ 4,608	$ 5,568	$ (23,841)	$ 1,457	$ 24,685

Subsequent Events (Narrative) (

Subsequent Events (Narrative) (Details) $ / shares in Units, $ in Thousands	Feb. 22, 2019USD ($)ft²$ / shares	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018USD ($)
Subsequent Event [Line Items]
Dividends payable, date payable		Oct. 5, 2017	Jul. 6, 2017	Apr. 5, 2017	Jan. 5, 2017
Dividends payable, date of record		Sep. 22, 2017	Jun. 16, 2017	Mar. 16, 2017	Dec. 16, 2016
Assets held for sale | $						$ 71,800
Liabilities held for sale | $						$ 24,349
Subsequent Event
Subsequent Event [Line Items]
Acres Of Land Contributed | ft²	118,000
Dividends payable, date declared	Feb. 22, 2019
Dividends payable, date payable	Apr. 4, 2019
Dividends payable, date of record	Mar. 20, 2019
Cash dividend payable per common share | $ / shares	$ 0.44
Assets held for sale | $	$ 71,800
Subsequent Event | Series B Preferred Stock
Subsequent Event [Line Items]
Dividends payable, date declared	Feb. 22, 2019
Dividends payable, date payable	Apr. 15, 2019
Dividends payable, date of record	Mar. 31, 2019
Cash dividend payable per common share | $ / shares	$ 1.63
Subsequent Event | Series A Preferred Stock
Subsequent Event [Line Items]
Dividends payable, date declared	Feb. 22, 2019
Dividends payable, date payable	Apr. 15, 2019
Dividends payable, date of record	Mar. 31, 2019
Cash dividend payable per common share | $ / shares	$ 0.45

Schedule II - Valuation and Q_2

Schedule II - Valuation and Qualifying Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Allowance for doubtful accounts
Balance at beginning of period	$ 11,453	$ 4,217	$ 5,063
Charge to expenses	(2,275)	7,375	1,752
Additions/(deductions)	(5,414)	(139)	(2,598)
Balance at end of period	3,764	11,453	4,217
Valuation Allowance for Deferred Tax Assets [Member]
Balance at beginning of period	713	393	393
Charge to expenses	7,648	320
Balance at end of period	$ 8,361	$ 713	$ 393

Schedule III - Real Estate In_2

Schedule III - Real Estate Investments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Initial costs of land	$ 51,156
Initial costs of buildings and improvements	364,686
Initial costs of construction in progress	208,608
Costs capitalized subsequent to acquisition, Land	54,385
Costs capitalized subsequent to acquisition, Buildings and improvements	1,552,565
Costs capitalized subsequent to acquisition, Construction in progress	581,455
Gross carrying amount, Land	105,541
Gross carrying amount, Buildings and improvements	1,917,251
Gross carrying amount, Construction in progress	790,064
Accumulated depreciation and amortization	(467,644)	$ (394,823)	$ (317,834)	$ (239,936)
Owned Properties
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Initial costs of land	51,156
Initial costs of buildings and improvements	303,614
Initial costs of construction in progress	208,608
Costs capitalized subsequent to acquisition, Land	54,385
Costs capitalized subsequent to acquisition, Buildings and improvements	1,569,440
Costs capitalized subsequent to acquisition, Construction in progress	572,099
Gross carrying amount, Land	105,541
Gross carrying amount, Buildings and improvements	1,873,054
Gross carrying amount, Construction in progress	780,707
Accumulated depreciation and amortization	(436,700)
Owned Properties | Atlanta, Georgia (Atlanta-Metro) [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Initial costs of land	12,647
Initial costs of buildings and improvements	35,473
Costs capitalized subsequent to acquisition, Land	7,769
Costs capitalized subsequent to acquisition, Buildings and improvements	457,973
Costs capitalized subsequent to acquisition, Construction in progress	88,253
Gross carrying amount, Land	20,416
Gross carrying amount, Buildings and improvements	493,446
Gross carrying amount, Construction in progress	88,253
Accumulated depreciation and amortization	$ (162,808)
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	339,807
Costs capitalized subsequent to acquisition, Construction in progress	99,445
Gross carrying amount, Land	8,606
Gross carrying amount, Buildings and improvements	345,615
Gross carrying amount, Construction in progress	99,445
Accumulated depreciation and amortization	$ (40,650)
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
Costs capitalized subsequent to acquisition, Land	180
Costs capitalized subsequent to acquisition, Buildings and improvements	241,898
Costs capitalized subsequent to acquisition, Construction in progress	67,932
Gross carrying amount, Land	2,180
Gross carrying amount, Buildings and improvements	253,098
Gross carrying amount, Construction in progress	67,932
Accumulated depreciation and amortization	$ (60,731)
Date of acquisition	Mar. 20, 2010
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	130,150
Costs capitalized subsequent to acquisition, Construction in progress	115,331
Gross carrying amount, Land	9,400
Gross carrying amount, Buildings and improvements	130,150
Gross carrying amount, Construction in progress	133,095
Accumulated depreciation and amortization	$ (10,302)
Date of acquisition	Jul. 8, 2014
Owned Properties | Suwanee, Georgia [Member]
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	136,496
Costs capitalized subsequent to acquisition, Construction in progress	3,188
Gross carrying amount, Land	3,521
Gross carrying amount, Buildings and improvements	166,298
Gross carrying amount, Construction in progress	3,188
Accumulated depreciation and amortization	$ (66,678)
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	17,440
Costs capitalized subsequent to acquisition, Construction in progress	19,572
Gross carrying amount, Land	7,466
Gross carrying amount, Buildings and improvements	97,806
Gross carrying amount, Construction in progress	33,472
Accumulated depreciation and amortization	$ (6,585)
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	82,710
Costs capitalized subsequent to acquisition, Construction in progress	7,600
Gross carrying amount, Buildings and improvements	98,548
Gross carrying amount, Construction in progress	7,600
Accumulated depreciation and amortization	$ (40,466)
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	12,121
Costs capitalized subsequent to acquisition, Construction in progress	92
Gross carrying amount, Land	1,481
Gross carrying amount, Buildings and improvements	64,874
Gross carrying amount, Construction in progress	92
Accumulated depreciation and amortization	$ (11,522)
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	18,013
Costs capitalized subsequent to acquisition, Construction in progress	(5,269)
Gross carrying amount, Land	9,079
Gross carrying amount, Buildings and improvements	18,623
Gross carrying amount, Construction in progress	43,715
Accumulated depreciation and amortization	$ (1,195)
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	1,920
Costs capitalized subsequent to acquisition, Construction in progress	431
Gross carrying amount, Land	20,700
Gross carrying amount, Buildings and improvements	34,046
Gross carrying amount, Construction in progress	431
Accumulated depreciation and amortization	$ (3,972)
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	42,852
Costs capitalized subsequent to acquisition, Construction in progress	3,852
Gross carrying amount, Land	3,154
Gross carrying amount, Buildings and improvements	72,435
Gross carrying amount, Construction in progress	3,852
Accumulated depreciation and amortization	$ (18,586)
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	$ 53,009
Costs capitalized subsequent to acquisition, Land	17,325
Costs capitalized subsequent to acquisition, Buildings and improvements	63,245
Costs capitalized subsequent to acquisition, Construction in progress	131,942
Gross carrying amount, Land	17,325
Gross carrying amount, Buildings and improvements	63,245
Gross carrying amount, Construction in progress	184,951
Accumulated depreciation and amortization	$ (1,704)
Date of acquisition	Aug. 9, 2017
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, Construction in progress	4,894
Gross carrying amount, Construction in progress	$ 29,562
Date of acquisition	Aug. 11, 2017
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	14,178
Gross carrying amount, Construction in progress	$ 39,835
Date of acquisition	Oct. 3, 2017
Owned Properties | Miami, Florida [Member]
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	24,080
Costs capitalized subsequent to acquisition, Construction in progress	90
Gross carrying amount, Land	1,777
Gross carrying amount, Buildings and improvements	31,035
Gross carrying amount, Construction in progress	90
Accumulated depreciation and amortization	$ (11,044)
Date of acquisition	Mar. 6, 2008
Owned Properties | Lenexa, Kansas [Member]
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	735
Gross carrying amount, Land	436
Gross carrying amount, Buildings and improvements	3,835
Accumulated depreciation and amortization	$ (457)
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	20,568
Gross carrying amount, Construction in progress	$ 45,194
Date of acquisition	Mar. 2, 2018
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	(16,875)
Costs capitalized subsequent to acquisition, Construction in progress	9,356
Gross carrying amount, Buildings and improvements	44,197
Gross carrying amount, Construction in progress	9,356
Accumulated depreciation and amortization	(30,944)
Leased Properties | Leased Facilities Acquired In 2015 Member
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	(37,471)
Costs capitalized subsequent to acquisition, Construction in progress	382
Gross carrying amount, Buildings and improvements	21,616
Gross carrying amount, Construction in progress	382
Accumulated depreciation and amortization	$ (18,586)
Date of acquisition	Jun. 16, 2015
Leased Properties | Jersey City, New Jersey [Member]
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	19,745
Costs capitalized subsequent to acquisition, Construction in progress	8,952
Gross carrying amount, Buildings and improvements	21,730
Gross carrying amount, Construction in progress	8,952
Accumulated depreciation and amortization	$ (11,757)
Date of acquisition	Nov. 1, 2006
Leased Properties | Overland Park, Kansas [Member]
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Costs capitalized subsequent to acquisition, Buildings and improvements	$ 851
Costs capitalized subsequent to acquisition, Construction in progress	22
Gross carrying amount, Buildings and improvements	851
Gross carrying amount, Construction in progress	22
Accumulated depreciation and amortization	$ (601)

Schedule III - Real Estate In_3

Schedule III - Real Estate Investments - Amount that Tax Basis of Net Real Estate Assets Less Than the Reported Amounts (Details) $ in Millions	Dec. 31, 2018USD ($)
Schedule III - Real Estate Investments [Abstract]
Tax Basis of Investments, Cost for Income Tax Purposes	$ 3,030

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, 2018	Dec. 31, 2017	Dec. 31, 2016
Property
Balance, beginning of period	$ 2,357,322	$ 1,964,857	$ 1,583,153
Disposals	(43,616)	(18,198)	(8,946)
Additions (acquisitions and improvements)	499,150	410,663	390,650
Balance, end of period	2,812,856	2,357,322	1,964,857
Accumulated depreciation
Balance, beginning of period	(394,823)	(317,834)	(239,936)
Disposals	30,139	13,970	6,761
Additions (depreciation and amortization expense)	(102,960)	(90,959)	(84,659)
Balance, end of period	$ (467,644)	$ (394,823)	$ (317,834)