CONSOLIDATED FINANCIAL STATEMENTS STATEMENTS OF CASH FLOW - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash flow from operating activities:
Net income (loss)	$ 5,481	$ 1,457	$ 24,685	$ 24,129
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization		136,585	120,805	83,605
Above/Below Market Lease Amortization		865	659	(117)
Amortization of deferred loan costs		3,640	3,285	3,181
Amortization of senior notes discount		229	261	247
Loss on extinguishment of debt		19,912
Equity-based compensation expense		13,863	10,584	6,964
Bad debt expense		3,519	1,752	1,323
Write off of deferred loan costs		80	224	468
Deferred tax benefit		(10,742)	(10,171)	(10,065)
Loss on sale of property				(164)
Non-cash transaction, integration and impairment costs		9,027	1,927	3,117
Changes in operating assets and liabilities
Rents and other receivables, net		(12,881)	(17,101)	(1,138)
Prepaid expenses		755	158	(2,182)
Other assets		282	(561)	(5,016)
Accounts payable and accrued liabilities		(5,071)	6,290	9,467
Advance rents, security deposits and other liabilities		5,491	5,959	(763)
Deferred income		3,312	5,038	(3,597)
Net cash provided by operating activities		170,323	153,794	109,787
Cash flow from investing activities:
Proceeds from sale of property				648
Acquisitions, net of cash acquired		(127,038)	(173,067)	(292,685)
Additions to property and equipment		(307,314)	(279,905)	(320,058)
Net cash used in investing activities		(434,352)	(452,972)	(612,095)
Cash flow from financing activities:
Credit facility proceeds		888,000	574,000	671,162
Credit facility repayments		(696,000)	(459,002)	(386,998)
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		(10,862)	(4,177)	(3,649)
Payment of cash dividends		(74,592)	(62,585)	(45,892)
Distribution to noncontrolling interests		(10,289)	(9,619)	(8,865)
Proceeds from exercise of stock options		4,972	858	559
Payment of tax withholdings related to equity based awards		(4,725)	(2,584)	(1,088)
Principal payments on capital lease obligations		(12,224)	(12,600)	(7,677)
Dulles, VA Vault Capital Lease Repayment		(17,785)
Mortgage principal debt repayments		(54)		(86,600)
Equity proceeds, net of costs		107,549	275,663	369,372
Net cash provided by financing activities		262,692	299,954	500,324
Net (decrease) increase in cash and cash equivalents		(1,337)	776	(1,984)
Cash and cash equivalents, beginning of period		9,580	8,804	10,788
Cash and cash equivalents, end of period	9,580	8,243	9,580	8,804
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION
Cash paid for interest (excluding deferred financing costs and amounts capitalized)		29,934	19,897	18,027
Noncash investing and financing activities:
Accrued capital additions		75,965	40,431	52,552
Accrued deferred financing costs		458	39	1
Accrued equity issuance costs		25		57
Capital lease and lease financing obligations assumed				43,832
Acquisitions, net of cash acquired:
Land	7,602	9,363	7,602	3,030
Buildings, improvements and equipment	80,975	14,341	80,975	80,818
Construction in Progress	62,884	103,334	62,884	12,127
Rents and other receivables, net	(2,042)		(2,042)	13,704
Acquired intangibles	34,521		34,521	93,400
Deferred costs	4,414		4,414
Prepaid expenses	574		574	1,653
Goodwill			(7,895)	174,697
Other assets	309		309	633
Capital lease and lease financing obligations				43,832
Accounts payable and accrued liabilities	(922)		(922)	(8,586)
Advance rents, security deposits and other liabilities	(1,343)		(1,343)	(2,468)
Deferred income	35		35	(10,818)
Deferred income taxes	(6,045)		(6,045)	(21,673)
Total acquisitions, net of cash acquired		127,038	173,067	292,685
Qualitytech, LP
Cash flow from operating activities:
Net income (loss)	5,481	1,457	24,685	24,129
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization		136,585	120,805	83,605
Above/Below Market Lease Amortization		865	659	(117)
Amortization of deferred loan costs		3,640	3,285	3,181
Amortization of senior notes discount		229	261	247
Loss on extinguishment of debt		19,912
Equity-based compensation expense		13,863	10,584	6,964
Bad debt expense		3,519	1,752	1,323
Write off of deferred loan costs		80	224	468
Deferred tax benefit		(10,742)	(10,171)	(10,065)
Loss on sale of property				(164)
Non-cash transaction, integration and impairment costs		9,027	1,927	3,117
Changes in operating assets and liabilities
Rents and other receivables, net		(12,881)	(17,101)	(1,138)
Prepaid expenses		755	158	(2,182)
Other assets		282	(561)	(5,016)
Accounts payable and accrued liabilities		(5,071)	6,290	9,467
Advance rents, security deposits and other liabilities		5,491	5,959	(763)
Deferred income		3,312	5,038	(3,597)
Net cash provided by operating activities		170,323	153,794	109,787
Cash flow from investing activities:
Proceeds from sale of property				648
Acquisitions, net of cash acquired		(127,038)	(173,067)	(292,685)
Additions to property and equipment		(307,314)	(279,905)	(320,058)
Net cash used in investing activities		(434,352)	(452,972)	(612,095)
Cash flow from financing activities:
Credit facility proceeds		888,000	574,000	671,162
Credit facility repayments		(696,000)	(459,002)	(386,998)
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		(10,862)	(4,177)	(3,649)
Payment of cash dividends		(74,592)	(62,585)	(45,892)
Partnership distributions		(10,289)	(9,619)	(8,865)
Proceeds from exercise of stock options		4,972	858	559
Payment of tax withholdings related to equity based awards		(4,725)	(2,584)	(1,088)
Principal payments on capital lease obligations		(12,224)	(12,600)	(7,677)
Dulles, VA Vault Capital Lease Repayment		(17,785)
Mortgage principal debt repayments		(54)		(86,600)
Equity proceeds, net of costs		107,549	275,663	369,372
Net cash provided by financing activities		262,692	299,954	500,324
Net (decrease) increase in cash and cash equivalents		(1,337)	776	(1,984)
Cash and cash equivalents, beginning of period		9,580	8,804	10,788
Cash and cash equivalents, end of period	9,580	8,243	9,580	8,804
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION
Cash paid for interest (excluding deferred financing costs and amounts capitalized)		29,934	19,897	18,027
Noncash investing and financing activities:
Accrued capital additions		75,965	40,431	52,552
Accrued deferred financing costs		458	39	1
Accrued equity issuance costs		25		57
Capital lease and lease financing obligations assumed				43,832
Acquisitions, net of cash acquired:
Land	7,602	9,363	7,602	3,030
Buildings, improvements and equipment	80,975	14,341	80,975	80,818
Construction in Progress	62,884	103,334	62,884	12,127
Rents and other receivables, net	(2,042)		(2,042)	13,704
Acquired intangibles	34,521		34,521	93,400
Deferred costs	4,414		4,414
Prepaid expenses	574		574	1,653
Goodwill			(7,895)	174,697
Other assets	309		309	633
Capital lease and lease financing obligations				43,832
Accounts payable and accrued liabilities	(922)		(922)	(8,586)
Advance rents, security deposits and other liabilities	(1,343)		(1,343)	(2,468)
Deferred income	35		35	(10,818)
Deferred income taxes	$ (6,045)		(6,045)	(21,673)
Total acquisitions, net of cash acquired		$ 127,038	$ 173,067	$ 292,685