Dupont Fabros Technology 10-K 25 Feb 15 2014 FY Annual report Financial data

Document_and_Entity_Informatio

Document and Entity Information Document (USD $)	12 Months Ended
In Millions, except Share data, unless otherwise specified	Dec. 31, 2014	Feb. 20, 2015	Jun. 30, 2014
Entity Information [Line Items]
Document Period End Date	31-Dec-14
Document Fiscal Year Focus	2014
Document Fiscal Period Focus	FY
Amendment Flag	FALSE
Entity Registrant Name	DUPONT FABROS TECHNOLOGY, INC.
Entity Central Index Key	1407739
Current Fiscal Year End Date	-19
Entity Filer Category	Large Accelerated Filer
Document Type	10-K
Entity Common Stock, Shares Outstanding		66,079,804
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$1,756
DuPont Fabros Technology, L.P. [Member]
Entity Information [Line Items]
Document Period End Date	31-Dec-14
Document Fiscal Year Focus	2014
Document Fiscal Period Focus	FY
Amendment Flag	FALSE
Entity Registrant Name	DUPONT FABROS TECHNOLOGY, L.P.
Entity Central Index Key	1418175
Current Fiscal Year End Date	-19
Entity Filer Category	Non-accelerated Filer
Document Type	10-K
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes

Consolidated_Balance_Sheets

Consolidated Balance Sheets (USD $)	Dec. 31, 2014		Dec. 31, 2013
In Thousands, unless otherwise specified
ASSETS
Land	$83,793		$75,956
Buildings and improvements	2,623,539		2,420,986
Income producing property	2,707,332		2,496,942
Less: accumulated depreciation	-504,869		-413,394
Net income producing property	2,202,463		2,083,548
Construction in progress and land held for development	358,965	[1]	302,068
Net real estate	2,561,428		2,385,616
Cash and cash equivalents	29,598		38,733
Rents and other receivables	8,113		12,674
Deferred rent, net	142,365		150,038
Lease contracts above market value, net	8,054		9,154
Deferred costs, net	38,495		39,866
Prepaid expenses and other assets	48,295		44,507
Total assets	2,836,348		2,680,588
Liabilities:
Line of credit	60,000		0
Mortgage notes payable	115,000		115,000
Unsecured Term Loan	250,000		154,000
Unsecured notes payable	600,000		600,000
Accounts payable and accrued liabilities	26,973		23,566
Construction costs payable	32,949		45,444
Accrued interest payable	10,759		9,983
Dividend and distribution payable	39,981		25,971
Lease contracts below market value, net	7,037		10,530
Prepaid rents and other liabilities	65,174		56,576
Total liabilities	1,207,873		1,041,070
Redeemable noncontrolling interests - operating partnership	513,134		387,244
Commitments and contingencies	0		0
Stockholders’ equity:
Common stock, $.001 par value, 250,000,000 shares authorized, 66,061,804 shares issued and outstanding at December 31, 2014 and 65,205,274 shares issued and outstanding at December 31, 2013	66		65
Additional paid in capital	764,025		900,959
Retained earnings (accumulated deficit)	0		0
Total stockholders’ equity	1,115,341		1,252,274
Total liabilities and stockholders’ equity	2,836,348		2,680,588
Series A cumulative redeemable perpetual preferred stock [Member]
Stockholders’ equity:
Preferred stock, $.001 par value, 50,000,000 shares authorized	185,000		185,000
Series B cumulative redeemable perpetual preferred stock [Member]
Stockholders’ equity:
Preferred stock, $.001 par value, 50,000,000 shares authorized	166,250		166,250
DuPont Fabros Technology, L.P. [Member]
ASSETS
Land	83,793		75,956
Buildings and improvements	2,623,539		2,420,986
Income producing property	2,707,332		2,496,942
Less: accumulated depreciation	-504,869		-413,394
Net income producing property	2,202,463		2,083,548
Construction in progress and land held for development	358,965		302,068
Net real estate	2,561,428		2,385,616
Cash and cash equivalents	25,380		34,514
Rents and other receivables	8,113		12,674
Deferred rent, net	142,365		150,038
Lease contracts above market value, net	8,054		9,154
Deferred costs, net	38,495		39,866
Prepaid expenses and other assets	48,295		44,507
Total assets	2,832,130		2,676,369
Liabilities:
Line of credit	60,000		0
Mortgage notes payable	115,000		115,000
Unsecured Term Loan	250,000		154,000
Unsecured notes payable	600,000		600,000
Accounts payable and accrued liabilities	26,973		23,566
Construction costs payable	32,949		45,444
Accrued interest payable	10,759		9,983
Dividend and distribution payable	39,981		25,971
Lease contracts below market value, net	7,037		10,530
Prepaid rents and other liabilities	65,174		56,576
Total liabilities	1,207,873		1,041,070
Redeemable noncontrolling interests - operating partnership	513,134		387,244
Redeemable partnership units	513,134		387,244
Commitments and contingencies	0		0
Stockholders’ equity:
Total liabilities and stockholders’ equity	2,832,130		2,676,369
Partners’ capital:
General partner’s capital, common units, 662,373 issued and outstanding at December 31, 2014 and December 31, 2013	7,619		9,110
Total partners’ capital	1,111,123		1,248,055
DuPont Fabros Technology, L.P. [Member] | Series A Preferred Units [Member]
Partners’ capital:
Limited partners' capital	185,000		185,000
DuPont Fabros Technology, L.P. [Member] | Series B Preferred Units [Member]
Partners’ capital:
Limited partners' capital	166,250		166,250
DuPont Fabros Technology, L.P. [Member] | Common units [Member]
Partners’ capital:
Limited partners' capital	752,254		887,695
DuPont Fabros Technology, L.P. [Member] | Series A cumulative redeemable perpetual preferred stock [Member]
Partners’ capital:
Limited partners' capital	185,000		185,000
DuPont Fabros Technology, L.P. [Member] | Series B cumulative redeemable perpetual preferred stock [Member]
Partners’ capital:
Limited partners' capital	$166,250		$166,250
[1]	(1)Properties located in Ashburn, VA (ACC7 Phases II-IV and ACC8); Piscataway, NJ (NJ1 Phase II), Elk Grove Village, IL (CH2) and Santa Clara, CA (SC1 Phase IIB and SC2).

Consolidated_Balance_Sheets_Pa

Consolidated Balance Sheets (Parenthetical) (USD $)	Dec. 31, 2014	Dec. 31, 2013
Preferred stock, par value	$0.00	$0.00
Preferred stock, shares authorized	50,000,000	50,000,000
Common stock, par value	$0.00	$0.00
Common stock, shares authorized	250,000,000	250,000,000
Common stock, shares issued	66,061,804	65,205,274
Common stock, shares outstanding	66,061,804	65,205,274
General Partners' Capital Account, Units Issued	662,373	662,373
General partners' capital, units outstanding	662,373	662,373
Series A cumulative redeemable perpetual preferred units [Member]
Limited partners' capital, common units issued	7,400,000	7,400,000
Limited partners' capital, common units outstanding	7,400,000	7,400,000
Series B cumulative redeemable perpetual preferred units [Member]
Limited partners' capital, common units issued	6,650,000	6,650,000
Limited partners' capital, common units outstanding	6,650,000	6,650,000
Limited partners' common units [Member]
Limited partners' capital, common units issued	65,399,431	64,542,901
Limited partners' capital, common units outstanding	65,399,431	64,542,901
Series A cumulative redeemable perpetual preferred stock [Member]
Preferred stock, shares issued	7,400,000	7,400,000
Preferred stock, shares outstanding	7,400,000	7,400,000
Series B cumulative redeemable perpetual preferred stock [Member]
Preferred stock, shares issued	6,650,000	6,650,000
Preferred stock, shares outstanding	6,650,000	6,650,000

Consolidated_Statements_of_Ope

Consolidated Statements of Operations (USD $)	12 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Revenues:
Base rent	$285,716	$265,695	$236,810
Recoveries from tenants	124,853	104,271	91,049
Other revenues	7,023	5,143	4,586
Total revenues	417,592	375,109	332,445
Expenses:
Property operating costs	117,339	103,522	94,646
Real estate taxes and insurance	14,195	14,380	12,689
Depreciation and amortization	96,780	93,058	89,241
General and administrative	17,181	16,261	17,024
Other expenses	9,222	3,650	6,919
Total expenses	254,717	230,871	220,519
Operating income	162,875	144,238	111,926
Interest income	116	137	168
Interest:
Expense incurred	-33,699	-46,443	-47,765
Amortization of deferred financing costs	-2,980	-3,349	-3,496
Loss on early extinguishment of debt	-1,701	-40,978	0
Net (loss) income	124,611	53,605	60,833
Noncontrolling Interest in Net Income (Loss) Operating Partnerships, Redeemable	18,704	5,214	7,803
Net (loss) income attributable to controlling interests	105,907	48,391	53,030
Preferred stock dividends	-27,245	-27,245	-27,053
Net (loss) income attributable to common shares	78,662	21,146	25,977
Earnings per share – basic:
Net income attributable to common shares	$1.19	$0.32	$0.41
Weighted average common shares outstanding	65,486,108	64,645,316	62,866,189
Earnings per share – diluted:
Net income attributable to common shares	$1.18	$0.32	$0.41
Weighted average common shares outstanding	66,086,379	65,474,039	63,754,006
DuPont Fabros Technology, L.P. [Member]
Revenues:
Base rent	285,716	265,695	236,810
Recoveries from tenants	124,853	104,271	91,049
Other revenues	7,023	5,143	4,586
Total revenues	417,592	375,109	332,445
Expenses:
Property operating costs	117,339	103,522	94,646
Real estate taxes and insurance	14,195	14,380	12,689
Depreciation and amortization	96,780	93,058	89,241
General and administrative	17,181	16,261	17,024
Other expenses	9,222	3,650	6,919
Total expenses	254,717	230,871	220,519
Operating income	162,875	144,238	111,926
Interest income	116	137	168
Interest:
Expense incurred	-33,699	-46,443	-47,765
Amortization of deferred financing costs	-2,980	-3,349	-3,496
Loss on early extinguishment of debt	-1,701	-40,978	0
Net (loss) income	124,611	53,605	60,833
Preferred stock dividends	-27,245	-27,245	-27,053
Net income attributable to common units	$97,366	$26,360	$33,780
Earnings per unit – basic:
Net income attributable to common units	$1.19	$0.32	$0.41
Weighted average common units outstanding	81,053,127	80,580,556	81,750,958
Earnings per unit – diluted:
Net income attributable to common units	$1.18	$0.32	$0.41
Weighted average common units outstanding	81,653,398	81,409,279	82,638,775

Consolidated_Statements_of_Sto

Consolidated Statements of Stockholders' Equity (USD $)	Total	PreferredStock/Units [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]
In Thousands, except Share data
Balance at Dec. 31, 2011	$1,207,135	$286,250	$63	$927,902	($7,080)
Balance, shares at Dec. 31, 2011	62,914,987
Net income attributable to controlling interests	53,030				53,030
Issuance of preferred stock	62,685	65,000		-2,315
Dividends declared on common stock	-39,229			-20,332	18,897
Dividends earned on preferred stock	-27,053				-27,053
Redemption of operating partnership units	6,800		0	6,800
Redemption of operating partnership units, shares	277,575
Issuance of stock awards	352		0	352
Issuance of stock awards, shares	157,025
Stock Issued During Period, Value, Stock Options Exercised	868		0	868
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period	113,955
Retirement and forfeiture of stock awards	-2,359		0	-2,359
Retirement and forfeiture of stock awards, shares	-122,613
Amortization of deferred compensation costs	7,033			7,033
Adjustments to redeemable noncontrolling interests – operating partnership	-2,830			-2,830
Balance at Dec. 31, 2012	1,266,432	351,250	63	915,119	0
Balance, shares at Dec. 31, 2012	63,340,929
Net income attributable to controlling interests	48,391				48,391
Issuance of preferred stock	0			0
Dividends declared on common stock	-61,560			-40,414	-21,146
Dividends earned on preferred stock	-27,245				-27,245
Redemption of operating partnership units	75,600		3	75,597
Redemption of operating partnership units, shares	3,115,269
Common stock repurchases	-37,792		-1	-37,791
Common stock repurchase, shares	-1,632,673
Issuance of stock awards	319		0	319
Issuance of stock awards, shares	216,209
Stock Issued During Period, Value, Stock Options Exercised	1,711		0	1,711
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period	250,472
Retirement and forfeiture of stock awards	-1,172		0	-1,172
Retirement and forfeiture of stock awards, shares	-84,932
Amortization of deferred compensation costs	6,381			6,381
Adjustments to redeemable noncontrolling interests – operating partnership	-18,791			-18,791
Balance at Dec. 31, 2013	1,252,274	351,250	65	900,959	0
Balance, shares at Dec. 31, 2013	65,205,274
Net income attributable to controlling interests	105,907				105,907
Dividends declared on common stock	-96,866			-18,204	-78,662
Dividends earned on preferred stock	-27,245				-27,245
Redemption of operating partnership units	6,100			6,100
Redemption of operating partnership units, shares	234,300
Common stock repurchase, shares	0
Issuance of stock awards	360			360
Issuance of stock awards, shares	163,187
Stock Issued During Period, Value, Stock Options Exercised	5,556		1	5,555
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period	507,056
Retirement and forfeiture of stock awards	-1,193			-1,193
Retirement and forfeiture of stock awards, shares	-48,013
Amortization of deferred compensation costs	6,565			6,565
Adjustments to redeemable noncontrolling interests – operating partnership	-136,117			-136,117
Balance at Dec. 31, 2014	$1,115,341	$351,250	$66	$764,025	$0
Balance, shares at Dec. 31, 2014	66,061,804

Consolidated_Statement_of_Part

Consolidated Statement of Partners' Capital (USD $)	Total	DuPont Fabros Technology, L.P. [Member]	DuPont Fabros Technology, L.P. [Member]	DuPont Fabros Technology, L.P. [Member]	DuPont Fabros Technology, L.P. [Member]
In Thousands, except Share data			Limited Partners' Capital - Preferred [Member]	Limited Partners' Capital - Common [Member]	General Partner's Capital [Member]
Balance at Dec. 31, 2011		$1,202,830	$286,250	$903,917	$12,663
Balance, units at Dec. 31, 2011				62,252,614	662,373
Net income	60,833	60,833		60,197	636
Issuance of OP units for preferred stock offering		62,694	65,000	-2,306
Common unit distributions		-50,912		-50,501	-411
Preferred unit distributions		-27,053		-26,770	-283
Issuance of OP units to DFT when redeemable partnership units redeemed, units	277,575	277,575		277,575
Issurance of OP units to DFT when redeemable partnership units redeemed	6,800	6,800		6,800
Issuance of OP units for stock awards, units				157,025
Issuance of OP units for stock awards		352		352
Issuance of OP units due to option exercises, units				113,955
Issuance of OP units due to option exercises		868		868
Retirement and forfeiture of OP units, units				-122,613
Retirement and forfeiture of OP units		-2,359		-2,359
Amortization of deferred compensation costs	7,033	7,033		7,033
Adjustments to redeemable partnership units		1,050		4,130	-3,080
Balance at Dec. 31, 2012		1,262,136	351,250	901,361	9,525
Balance, units at Dec. 31, 2012				62,678,556	662,373
Net income	53,605	53,605		53,060	545
Common unit distributions		-76,610		-75,981	-629
Preferred unit distributions		-27,245		-26,968	-277
Issuance of OP units to DFT when redeemable partnership units redeemed, units	3,115,269	3,115,269		3,115,269
Issurance of OP units to DFT when redeemable partnership units redeemed	75,600	75,600		75,600
Retirement of OP units for common stock repurchase, units				-1,632,673
Retirement of OP units for common stock repurchases		-37,792		-37,792
Issuance of OP units for stock awards, units				216,209
Issuance of OP units for stock awards		319		319
Issuance of OP units due to option exercises, units				250,472
Issuance of OP units due to option exercises		1,711		1,711
Retirement and forfeiture of OP units, units				-84,932
Retirement and forfeiture of OP units		-1,172		-1,172
Amortization of deferred compensation costs	6,381	6,381		6,381
Adjustments to redeemable partnership units		-8,878		-8,824	-54
Balance at Dec. 31, 2013		1,248,055	351,250	887,695	9,110
Balance, units at Dec. 31, 2013				64,542,901	662,373
Net income	124,611	124,611		123,362	1,249
Common unit distributions		-119,697		-118,723	-974
Preferred unit distributions		-27,245		-26,972	-273
Issuance of OP units to DFT when redeemable partnership units redeemed, units	234,300	234,300		234,300
Issurance of OP units to DFT when redeemable partnership units redeemed	6,100	6,100		6,100
Issuance of OP units for stock awards, units				163,187
Issuance of OP units for stock awards		360		360
Issuance of OP units due to option exercises, units				507,056
Issuance of OP units due to option exercises		5,556		5,556
Retirement and forfeiture of OP units, units				-48,013
Retirement and forfeiture of OP units		-1,193		-1,193
Amortization of deferred compensation costs	6,565	6,565		6,565
Adjustments to redeemable partnership units		-131,989		-130,496	-1,493
Balance at Dec. 31, 2014		$1,111,123	$351,250	$752,254	$7,619
Balance, units at Dec. 31, 2014				65,399,431	662,373

Consolidated_Statements_of_Cas

Consolidated Statements of Cash Flows (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Cash flow from operating activities
Net income	$124,611	$53,605	$60,833
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation and amortization	96,780	93,058	89,241
Write off of Deferred Debt Issuance Cost	1,701	40,978	0
Straight line rent	7,673	-6,920	-17,967
Amortization of deferred financing costs	-2,980	-3,349	-3,496
Amortization of lease contracts above and below market value	-2,393	-2,391	-3,194
Compensation paid with Company common shares	6,191	6,088	6,980
Changes in operating assets and liabilities
Rents and other receivables	4,561	-5,900	-2,452
Deferred costs	-2,552	-2,082	-1,278
Prepaid expenses and other assets	-5,637	-14,760	-5,854
Accounts payable and accrued liabilities	1,395	1,520	-1,112
Accrued interest payable	776	7,382	73
Prepaid rents and other liabilities	8,427	19,834	3,997
Net cash provided by operating activities	244,513	193,761	132,763
Cash flow from investing activities
Investments in real estate – development	-265,374	-129,332	-94,753
Payments to Acquire Land	0	-14,186	-3,830
Interest capitalized for real estate under development	-9,644	-3,774	-4,434
Improvements to real estate	-1,916	-5,757	-4,426
Additions to non-real estate property	-316	-71	-57
Net cash used in investing activities	-277,250	-153,120	-107,500
Line of credit:
Proceeds	60,000	102,000	48,000
Repayments	0	-120,000	-50,000
Mortgage notes payable:
Proceeds	0	115,000	0
Lump sum payoffs	0	-138,300	0
Repayments	0	-1,300	-5,200
Unsecured Term Loan:
Proceeds	96,000	154,000	0
Unsecured notes payable:
Proceeds	0	600,000	0
Repayments	0	-550,000	0
Payments of financing costs	-3,829	-18,200	-2,109
Payments for early extinguishment of debt	0	-32,544	0
Issuance of preferred stock, net of offering costs	0	0	62,685
Exercises of stock options, net	4,363	1,711	868
Common stock repurchases	0	-37,792	0
Dividends and distributions:
Common shares	-85,422	-57,927	-34,112
Preferred shares	-27,245	-27,245	-26,006
Redeemable noncontrolling interests – operating partnership	-20,265	-14,889	-10,213
Net cash provided by financing activities	23,602	-25,486	-16,087
Net increase (decrease) in cash and cash equivalents	-9,135	15,155	9,176
Cash and cash equivalents, beginning	38,733	23,578	14,402
Cash and cash equivalents, ending	29,598	38,733	23,578
Supplemental information:
Cash paid for interest	42,567	42,835	52,127
Deferred financing costs capitalized for real estate under development	601	226	277
Construction costs payable capitalized for real estate under development	32,949	45,444	6,334
Redemption of operating partnership units	6,100	75,600	6,800
Adjustments to redeemable noncontrolling interests – operating partnership	136,117	18,791	2,830
DuPont Fabros Technology, L.P. [Member]
Cash flow from operating activities
Net income	124,611	53,605	60,833
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation and amortization	96,780	93,058	89,241
Write off of Deferred Debt Issuance Cost	1,701	40,978	0
Straight line rent	7,673	-6,920	-17,967
Amortization of deferred financing costs	-2,980	-3,349	-3,496
Amortization of lease contracts above and below market value	-2,393	-2,391	-3,194
Compensation paid with Company common shares	6,191	6,088	6,980
Changes in operating assets and liabilities
Rents and other receivables	4,561	-5,900	-2,452
Deferred costs	-2,552	-2,082	-1,278
Prepaid expenses and other assets	-5,637	-14,760	-5,854
Accounts payable and accrued liabilities	1,396	1,520	-1,112
Accrued interest payable	776	7,382	73
Prepaid rents and other liabilities	8,427	19,834	3,997
Net cash provided by operating activities	244,514	193,761	132,763
Cash flow from investing activities
Investments in real estate – development	-265,374	-129,332	-94,753
Payments to Acquire Land	0	-14,186	-3,830
Interest capitalized for real estate under development	-9,644	-3,774	-4,434
Improvements to real estate	-1,916	-5,757	-4,426
Additions to non-real estate property	-316	-71	-57
Net cash used in investing activities	-277,250	-153,120	-107,500
Line of credit:
Proceeds	60,000	102,000	48,000
Repayments	0	-120,000	-50,000
Mortgage notes payable:
Proceeds	0	115,000	0
Lump sum payoffs	0	-138,300	0
Repayments	0	-1,300	-5,200
Unsecured Term Loan:
Proceeds	96,000	154,000	0
Unsecured notes payable:
Proceeds	0	600,000	0
Repayments	0	-550,000	0
Payments of financing costs	-3,829	-18,123	-2,109
Payments for early extinguishment of debt	0	-32,544	0
Issuance of preferred stock, net of offering costs	0	0	62,694
Exercises of stock options, net	4,363	1,711	868
Common stock repurchases	0	-37,792	0
Distributions	-132,932	-100,061	-70,331
Dividends and distributions:
Net cash provided by financing activities	23,602	-25,409	-16,078
Net increase (decrease) in cash and cash equivalents	-9,134	15,232	9,185
Cash and cash equivalents, beginning	34,514	19,282	10,097
Cash and cash equivalents, ending	25,380	34,514	19,282
Supplemental information:
Cash paid for interest	42,567	42,835	52,127
Deferred financing costs capitalized for real estate under development	601	226	277
Construction costs payable capitalized for real estate under development	32,949	45,444	6,334
Redemption of operating partnership units	6,100	75,600	6,800
Adjustments to redeemable noncontrolling interests – operating partnership	$131,989	($8,878)	($1,050)

1_Description_of_Business

1. Description of Business	12 Months Ended
	Dec. 31, 2014
Description of Business [Abstract]
Nature of Operations [Text Block]	Description of Business
	DuPont Fabros Technology, Inc. (“DFT”), through its controlling interest in DuPont Fabros Technology, L.P. (the “Operating Partnership” or “OP” and collectively with DFT and their operating subsidiaries, the “Company”), is a fully integrated, self-administered and self-managed company that owns, acquires, develops and operates wholesale data centers. DFT is a real estate investment trust, or REIT, for federal income tax purposes and is the sole general partner of the Operating Partnership, and as of December 31, 2014, owned 81.1% of the common economic interest in the Operating Partnership, of which 1.0% is held as general partnership units. Unless otherwise indicated or unless the context requires otherwise, all references in this report to “we,” “us,” “our,” “our Company” or “the Company” refer to DFT and the Operating Partnership, collectively. As of December 31, 2014, we held a fee simple interest in the following properties:
	•	11 operating data centers – ACC2, ACC3, ACC4, ACC5, ACC6, ACC7 Phase I, VA3, VA4, CH1, NJ1 Phase I and SC1 Phases I and IIA;
	•	two data centers currently under development - SC1 Phase IIB and CH2 Phase I ;
	•	data center projects available for future development – ACC7 Phases II-IV, CH2 Phases II-III and NJ1 Phase II; and
	•	land that may be used to develop additional data centers – ACC8 and SC2.
	In February 2015, our Board of Directors authorized the development of ACC7 Phase II.

2_Significant_Accounting_Polic

2. Significant Accounting Policies	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
Significant Accounting Policies [Text Block]	Significant Accounting Policies
	Basis of Presentation
	This report combines the annual reports on Form 10-K for the year ended December 31, 2014 of DuPont Fabros Technology, Inc. and DuPont Fabros Technology, L.P. References to “DFT” mean DuPont Fabros Technology, Inc. and its controlled subsidiaries; and references to the “Operating Partnership” or “OP” mean DuPont Fabros Technology, L.P. and its controlled subsidiaries.
	We believe combining the annual reports on Form 10-K of DFT and the Operating Partnership into this single report provides the following benefits:
	•	enhances investors’ understanding of DFT 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 in this report applies to both DFT and the Operating Partnership; and
	•	creates time and cost efficiencies through the preparation of one combined report instead of two separate reports.
	We operate DFT and the Operating Partnership as one business. The management of DFT consists of the same employees as the management of the Operating Partnership.
	We believe it is important for investors to understand the few differences between DFT and the Operating Partnership in the context of how DFT and the Operating Partnership operate as a consolidated company. DFT is a REIT, whose only material asset is its ownership of OP units of the Operating Partnership. As a result, DFT does not conduct business itself, other than acting as the sole general partner of the Operating Partnership, issuing public equity from time to time and guaranteeing unsecured debt of the Operating Partnership. DFT has not issued any indebtedness, but has guaranteed all of the unsecured debt of the Operating Partnership. The Operating Partnership holds all the real estate assets of the Company. Except for net proceeds from public equity issuances by DFT, which are contributed to the Operating Partnership in exchange for OP units or preferred units, the Operating Partnership generates all remaining capital required by our business. These sources include the Operating Partnership’s operations, its direct or indirect incurrence of indebtedness, and the issuance of partnership units.
	As general partner with control of the Operating Partnership, DFT consolidates the Operating Partnership for financial reporting purposes. The presentation of stockholders’ equity and partners’ capital are the main areas of difference between the consolidated financial statements of DFT and those of the Operating Partnership. The Operating Partnership’s capital includes preferred units and general and limited common units that are owned by DFT and the other partners. DFT’s stockholders’ equity includes preferred stock, common stock, additional paid in capital and retained earnings. The common limited partnership interests held by the limited partners (other than DFT) in the Operating Partnership are presented as “redeemable partnership units” in the Operating Partnership’s consolidated financial statements and as “redeemable noncontrolling interests-operating partnership” in DFT’s consolidated financial statements. The only difference between the assets and liabilities of DFT and the Operating Partnership as of December 31, 2014 is a $4.2 million bank account held by DFT that is not part of the Operating Partnership. Net income is the same for DFT and the Operating Partnership.
	The accompanying consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles, or GAAP. All significant intercompany accounts and transactions have been eliminated in the consolidated financial statements.
	We have one reportable segment consisting of investments in data centers located in the United States. All of our properties generate similar types of revenues and expenses related to customer rent and reimbursements and operating expenses. The delivery of our products is consistent across all properties and although services are provided to a range of customers, the types of services provided to them are limited to a few core principles. As such, the properties in our portfolio have similar economic characteristics and the nature of the products and services provided to our customers and the method to distribute such services are consistent throughout the portfolio.
	Use of Estimates
	The preparation of financial statements in conformity with GAAP requires us to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosures of contingent assets and liabilities at the date of the financial statements, and the reported amounts of revenue and expenses during the reporting period. Actual results could differ from those estimates.
	Property
	All capital improvements for the income-producing properties that extend their useful life are capitalized to individual building components, including interest and real estate taxes incurred during the period of development, and depreciated over their estimated useful lives. Interest is capitalized during the period of development based upon applying the property’s specific borrowing rate to the actual development costs expended up to specific borrowings and then applying our weighted-average borrowing rate to any residual development costs expended during the construction period. Interest is capitalized until the property has reached substantial completion and is ready for its intended use. Interest costs capitalized totaled $10.2 million, $4.0 million and $4.7 million for the years ended December 31, 2014, 2013 and 2012, respectively. We cease interest capitalization when a development is temporarily suspended or placed in service.
	We capitalize pre-development costs, including internal costs, incurred in pursuit of new development opportunities for which we currently believe future development is probable. Future development is dependent upon various factors, including zoning and regulatory approval, rental market conditions, construction costs and availability of capital. Pre-development costs incurred for which future development is not yet considered probable are expensed as incurred. In addition, if the status of such a pre-development opportunity changes, making future development no longer probable, any capitalized pre-development costs are written-off with a charge to expense. Furthermore, the revenue from incidental operations received from the current improvements in excess of any incremental costs are being recorded as a reduction of total capitalized costs of the development project and not as a part of net income. The capitalization of costs during the development of assets (including interest and related loan fees, property taxes and other direct and indirect costs) begins when development efforts commence and ends when the asset, or a portion of the asset, is substantially complete and ready for its intended use. For the years ended December 31, 2014, 2013 and 2012, we capitalized $4.5 million, $3.3 million and $3.1 million, respectively, of internal development and leasing costs on all of our data centers.
	The fair value of in-place leases consists of the following components, as applicable: (1) the estimated cost to replace the leases, including foregone rents during the period of finding a new customer, foregone recovery of customer pass-through, customer improvements, and other direct costs associated with obtaining a new customer (referred to as Tenant Origination Costs); (2) the estimated leasing commissions associated with obtaining a new customer (referred to as Leasing Commissions); and (3) the above/below market cash flow of the leases, determined by comparing the projected cash flows of the leases in place to projected cash flows of comparable market-rate leases (referred to as Lease Intangibles). Tenant Origination Costs are included in buildings and improvements in our accompanying consolidated balance sheets and are amortized as depreciation expense on a straight-line basis over the average remaining life of the underlying leases. Leasing Commissions are classified as deferred costs and are amortized as amortization expense on a straight-line basis over the remaining life of the underlying leases. Lease Intangible assets and liabilities are classified as lease contracts above and below market value, respectively, and amortized on a straight-line basis as decreases and increases, respectively, to rental revenue over the remaining life of the underlying leases. Should a customer terminate its lease, the unamortized portions of Leasing Commissions and Lease Intangibles associated with that lease are written off to amortization expense, or rental revenue, respectively.
	Depreciation on buildings is generally provided on a straight-line basis over 40 years from the date the buildings were placed in service. Building components are depreciated over the life of the respective improvement ranging from 10 to 40 years from the date the components were placed in service. Personal property is depreciated over three years to seven years. Depreciation expense was $92.3 million, $88.6 million and $84.6 million for the years ended December 31, 2014, 2013 and 2012, respectively. Included in these amounts is amortization expense related to tenant origination costs, which was $3.1 million for each of the years ended December 31, 2014, 2013 and 2012. Repairs and maintenance costs are expensed as incurred.
	We record impairment losses on long-lived assets used in operations or in development when events or changes in circumstances indicate that the assets might be impaired, and the estimated undiscounted cash flows to be generated by those assets are less than the carrying amounts. If circumstances indicating impairment of a long-lived asset are present, we would determine the fair value of that asset, and an impairment loss would be recognized in an amount equal to the excess of the carrying amount of the impaired asset over its fair value. We assess the recoverability of the carrying value of our assets on a property-by-property basis. No impairment losses were recorded during the three years ended December 31, 2014.
	We classify a data center property as held-for-sale when it meets the necessary criteria, which include when we commit to and actively embark on a plan to sell the asset, the sale is expected to be completed within one year under terms usual and customary for such sales, and actions required to complete the plan indicate that it is unlikely that significant changes to the plan will be made or that the plan will be withdrawn. Data center properties held-for-sale are carried at the lower of cost or fair value less costs to sell. As of December 31, 2014, there were no data center properties classified as held-for-sale.
	Cash and Cash Equivalents
	We consider all demand deposits and money market accounts purchased with a maturity date of three months or less, at the date of purchase, to be cash equivalents. Our account balances at one or more institutions exceed the Federal Deposit Insurance Corporation (“FDIC”) insurance coverage and, as a result, there is a concentration of credit risk related to amounts on deposit in excess of FDIC insurance coverage. We have not experienced any losses and believe that the risk is not significant.
	Deferred Costs
	Deferred costs, net in our accompanying consolidated balance sheets include both financing and leasing costs.
	Financing costs, which represent fees and other costs incurred in obtaining debt, are amortized using the effective-interest rate method or a method that approximates the effective-interest method, over the term of the loan and are included in amortization of deferred financing costs. In May 2014, we amended our unsecured revolving credit facility ("Unsecured Credit
	Facility"), which, due to the change in composition of lenders comprising the Unsecured Credit Facility's bank group, resulted in the partial write-off of unamortized deferred financing costs totaling $0.3 million. In July 2014, we amended our unsecured term loan agreement ("Unsecured Term Loan"), which, due to the change in composition of lenders comprising the Unsecured Term Loan's bank group, resulted in a loss on early extinguishment of debt of $1.4 million, which included a partial write-off of unamortized deferred financing costs of $0.7 million. In March 2013, we paid off the $138.3 million balance of the ACC5 Term Loan which resulted in a write-off of $1.7 million of unamortized deferred financing costs. In September and October 2013, we paid off the Unsecured Notes due 2017, which resulted in a write off of $6.7 million of unamortized deferred financing costs. Balances, net of accumulated amortization, at December 31, 2014 and 2013 are as follows (in thousands):
		December 31,
		2014				2013
	Financing costs	$	24,110			$	22,756
	Accumulated amortization	(6,820		)		(4,013		)
	Financing costs, net	$	17,290			$	18,743
	Leasing costs, which are either external fees and costs incurred in the successful negotiations of leases, internal costs expended in the successful negotiations of leases or the estimated leasing commissions resulting from the allocation of the purchase price of ACC2, VA3, VA4 and ACC4, are deferred and amortized over the terms of the related leases on a straight-line basis. If an applicable lease terminates prior to the expiration of its initial term, the carrying amount of the costs are written off to amortization expense. Leasing costs incurred for the years ended December 31, 2014, 2013 and 2012 are as follows:
		Year ended December 31,
		2014				2013			2012
	Costs incurred for new leases	$	2			$	0.9		$	1.3
	Costs incurred for renewals	0.2				1.2			—
	Costs incurred for re-leases	2				—			—
	Total leasing costs incurred	$	4.2			$	2.1		$	1.3
	Amortization of deferred leasing costs totaled $4.1 million, $4.1 million and $4.3 million for the years ended December 31, 2014, 2013 and 2012, respectively. Balances, net of accumulated amortization, at December 31, 2014 and 2013 are as follows (in thousands):
		December 31,
		2014				2013
	Leasing costs	$	52,358			$	48,312
	Accumulated amortization	(31,153		)		(27,189		)
	Leasing costs, net	$	21,205			$	21,123
	Inventory
	We maintain fuel inventory for our generators, which is recorded at the lower of cost (on a first-in, first-out basis) or market. As of December 31, 2014 and 2013, the fuel inventory was $4.3 million and $4.0 million, respectively, and is included in prepaid expenses and other assets in the accompanying consolidated balance sheets.
	Prepaid Rents
	Prepaid rents, typically prepayment of the following month’s rent, consist of payments received from customers prior to the time the payments are earned and are recognized as revenue in subsequent periods when earned.
	Rental Income
	We, as a lessor, have retained substantially all the risks and benefits of ownership and account for our leases as operating leases. For lease agreements that provide for scheduled fixed and determinable 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 and critical power have been provided to the customer. If the lease contains an early termination clause with a penalty payment, we determine the lease termination date by evaluating whether the penalty reasonably assures that the lease will not be terminated early. Lease inducements, which include free rent or cash payments to customers, are amortized as a reduction of rental income over the non-cancellable lease term. Straight-line rents receivable are included in deferred rent, net in the accompanying consolidated balance sheets. Lease intangible assets and liabilities that have resulted from above-market and below-market leases that were acquired are amortized on a straight-line basis as decreases and increases, respectively, to rental revenue over the remaining non-cancellable term of the underlying leases. If a lease terminates prior to the expiration of its initial term, the unamortized portion of lease intangibles associated with that lease will be written off to rental revenue. Balances, net of accumulated amortization, at December 31, 2014 and 2013 are as follows (in thousands):
		December 31,
		2014				2013
	Lease contracts above market value	$	23,100			$	23,100
	Accumulated amortization	(15,046		)		(13,946		)
	Lease contracts above market value, net	$	8,054			$	9,154
	Lease contracts below market value	$	39,375			$	39,375
	Accumulated amortization	(32,338		)		(28,845		)
	Lease contracts below market value, net	$	7,037			$	10,530
	Our policy is to record a reserve for losses on accounts receivable equal to the estimated uncollectible accounts. The estimate is based on our historical experience and a review of the current status of our receivables. As of December 31, 2014 and 2013, we had reserves against rents and other receivables of $4.9 million and $1.6 million, respectively. We also establish an appropriate allowance for doubtful accounts for receivables arising from the straight-lining of rents. These receivables arise from revenue recognized in excess of amounts currently due under the lease and are recorded as deferred rent in the accompanying consolidated balance sheets. As of December 31, 2014 and 2013, we had reserves against deferred rent of $3.7 million and $2.1 million, respectively.
	The reserves described above were set up for one customer that restructured its lease obligations with us during 2013. Under this restructuring, this customer's outstanding accounts receivable and deferred rent receivable related to the space that was returned to us were converted into a note receivable, the terms of which require the payment of principal and interest through December 31, 2016. Principal payments on the note are calculated on a ten-year amortization schedule with a final principal payment of the remaining note balance due on December 31, 2016. Additionally, under this restructuring, this customer deferred two-thirds of its base rent payments due for its lease at our NJ1 facility through July 2014, which were added to the note. Since that restructuring, we received all rent obligations and note payments due from this customer through the end of 2014. In January 2015, this customer informed us that they would be halting base rent payments and would pay only its monthly operating expenses, direct electric charges and management fees and its quarterly note payments until its company is sold or new funding sources are obtained. In February 2015, this customer filed a voluntary petition for relief under chapter 11 of the United States Bankruptcy Code.
	Due to the uncertainty surrounding this customer's ability to repay its note on its December 31, 2016 maturity, we increased the provision for bad debts related to this note by $2.4 million. Furthermore, to date, we have applied the interest portion of all note payments received, totaling $1.0 million, to the note principal balance on our consolidated balance sheet. The note balance as of December 31, 2014 and 2013 was $6.6 million and $5.7 million, respectively, which is recorded within rents and other receivables, net in our accompanying consolidated balance sheets. The note receivable balance, net of reserves and interest applied to the principal, as of December 31, 2014 and 2013 was $1.7 million and $4.1 million, respectively.
	Due to the uncertainty surrounding this customer's ability to pay its contractual rent obligations, we also reserved an additional $1.5 million of this customer's deferred rent receivable balance, resulting in a total reserve of $3.7 million on its deferred rent receivable balance of $9.5 million as of December 31, 2014.
	Customer leases generally contain provisions under which the customers reimburse us for a portion of operating expenses and real estate taxes incurred by the property. Recoveries from tenants are included in revenue in the consolidated statements of operations in the period the applicable expenditures are incurred. Most of our leases also provide us with a property management fee based on a percentage of base rent collected and property-level operating expenses, other than charges for power used by customers to run their servers and cool their space. Property management fees are included in base rent in the accompanying consolidated statements of operations in the applicable period in which they are earned.
Other Revenue
Other revenue primarily consists of services provided to customers on a non-recurring basis. This includes projects such as the purchase and installation of circuits, racks, breakers and other customer requested items. Revenue is recognized on a completed contract basis when the project is finished and ready for the customer's use. This method is consistently applied for all periods presented. Costs of providing these services are included in other expenses in the accompanying consolidated statements of operations.
Income Taxes
DFT elected to be taxed as a REIT under the Internal Revenue Code of 1986, as amended (the “Code”), commencing with the taxable year ended December 31, 2007. In general, a REIT that meets certain organizational and operational requirements and distributes at least 90 percent of its REIT taxable income to its shareholders in a year will not be subject to income tax to the extent of the income it distributes. We currently qualify and intend to continue to qualify as a REIT under the Code. As a result, no provision for federal income taxes on income from continuing operations is required, except for taxes on certain property sales and on income, if any, of DF Technical Services, LLC, our taxable REIT subsidiary (“TRS”). If we fail to qualify as a REIT in any taxable year, we will be subject to federal income tax (including any applicable alternative minimum tax) on our income at regular corporate tax rates for the year in which we do not qualify and the succeeding four years. Although we expect to qualify for taxation as a REIT, we may be subject to state and local income and franchise taxes and to federal income and excise taxes on any undistributed income.
As of December 31, 2014 and 2013, we did not have any unrecognized tax benefits. We do not believe that there will be any material changes in our unrecognized tax positions over the next 12 months. We are subject to examination by the respective taxing authorities for the tax years 2011 through 2014.
We account for income taxes using the asset and liability method under which 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. Valuation allowances are provided if based upon the weight of the available evidence, it is more likely than not that some or all of the deferred tax assets will not be realized.
In general, a TRS may perform non-customary services for customers, hold assets that DFT cannot hold directly and generally may engage in any real estate or non-real estate related business. A TRS is subject to corporate federal and state income taxes on its taxable income at regular statutory tax rates. For the year ended December 31, 2014, we incurred $0.1 million of income taxes. For the years ended December 31, 2013 and 2012, we incurred no income taxes.
As of December 31, 2014, the TRS had a deferred tax asset of $5.5 million, comprised entirely of its net operating loss carryforward, and a deferred tax liability of $6.1 million, primarily comprised of a temporary depreciation difference, resulting in a net deferred tax liability of $0.6 million. As of December 31, 2014, we recorded deferred income tax expense of $0.2 million related to this deferred tax liability. As of December 31, 2013, the TRS had a deferred tax asset of $2.5 million, comprised entirely of its net operating loss carryforward, and a deferred tax liability of $2.5 million, primarily comprised of a temporary depreciation difference, resulting in a net deferred tax liability of $0. As of December 31, 2014, the net operating loss carryforwards of the TRS totaled approximately $5.5 million, which will begin to expire in 2031 if not utilized by then.
Redeemable Noncontrolling Interests – Operating Partnership / Redeemable Partnership Units
Redeemable noncontrolling interests – operating partnership, as presented on DFT’s consolidated balance sheets, represent the limited partnership interests in the Operating Partnership (“OP units”) held by individuals and entities other than DFT. These interests are also presented on the Operating Partnership’s consolidated balance sheets, referred to as “redeemable partnership units.” Accordingly, the following discussion related to redeemable noncontrolling interests – operating partnership of DFT refers equally to redeemable partnership units of the Operating Partnership.
Redeemable noncontrolling interests – operating partnership, which require cash payment, or allow settlement in shares, but with the ability to deliver the shares outside of the control of DFT, are reported outside of the permanent equity section of the consolidated balance sheets of DFT and the Operating Partnership. Redeemable noncontrolling interests – operating partnership are adjusted for income, losses and distributions allocated to OP units not held by DFT (normal noncontrolling interest accounting amount). Adjustments to redeemable noncontrolling interests – operating partnership are recorded to reflect increases or decreases in the ownership of the Operating Partnership by holders of OP units, including the redemptions of OP units for cash or in exchange for shares of DFT’s common stock. If such adjustments result in redeemable noncontrolling interests – operating partnership being recorded at less than the redemption value of the OP units, redeemable noncontrolling interests – operating partnership are further adjusted to their redemption value (see Note 9). Redeemable noncontrolling interests – operating partnership are recorded at the greater of the normal noncontrolling interest accounting amount or redemption value. The following is a summary of activity for redeemable noncontrolling interests – operating partnership for the years ended December 31, 2014, 2013 and 2012 (dollars in thousands):
	OP Units
	Number			Amount
Balance at December 31, 2011	19,064,381			$	461,739
Net income attributable to redeemable noncontrolling interests – operating partnership	—			7,803
Distributions declared	—			(11,683		)
Redemption of operating partnership units	(277,575	)		(6,800		)
Adjustments to redeemable noncontrolling interests – operating partnership	—			2,830
Balance at December 31, 2012	18,786,806			$	453,889
Net income attributable to redeemable noncontrolling interests – operating partnership	—			5,214
Distributions declared	—			(15,050		)
Redemption of operating partnership units	(3,115,269	)		(75,600		)
Adjustments to redeemable noncontrolling interests – operating partnership	—			18,791
Balance at December 31, 2013	15,671,537			$	387,244
Net income attributable to redeemable noncontrolling interests – operating partnership	—			18,704
Distributions declared	—			(22,831		)
Redemption of operating partnership units	(234,300	)		(6,100		)
Adjustments to redeemable noncontrolling interests – operating partnership	—			136,117
Balance at December 31, 2014	15,437,237			$	513,134
The following is a summary of activity for redeemable partnership units for the years ended December 31, 2014, 2013 and 2012 (dollars in thousands):
	OP Units
	Number			Amount
Balance at December 31, 2011	19,064,381			$	461,739
Redemption of operating partnership units	(277,575	)		(6,800		)
Adjustments to redeemable partnership units	—			(1,050		)
Balance at December 31, 2012	18,786,806			$	453,889
Redemption of operating partnership units	(3,115,269	)		(75,600		)
Adjustments to redeemable partnership units	—			8,955
Balance at December 31, 2013	15,671,537			$	387,244
Redemption of operating partnership units	(234,300	)		(6,100		)
Adjustments to redeemable partnership units	—			131,990
Balance at December 31, 2014	15,437,237			$	513,134
Net income is allocated to controlling interests and redeemable noncontrolling interests – operating partnership in accordance with the limited partnership agreement of the Operating Partnership. The following is a summary of net income attributable to controlling interests and transfers to redeemable noncontrolling interests – operating partnership for the years ended December 31, 2014, 2013 and 2012 (dollars in thousands):
	Year ended December 31,
	2014				2013			2012
Net income attributable to controlling interests	$	105,907			$	48,391		$	53,030
Transfers from noncontrolling interests:
Net change in the Company’s common stock and additional paid in capital due to the redemption of OP units and other adjustments to redeemable noncontrolling interests – operating partnership	(130,017		)		56,809			3,970
	$	(24,110	)		$	105,200		$	57,000
Earnings Per Share of DFT
Basic earnings per share is calculated by dividing the net income attributable to common shares for the period by the weighted average number of common shares outstanding during the period using the two class method. Diluted earnings per share is calculated by dividing the net income attributable to common shares for the period by the weighted average number of common and dilutive securities outstanding during the period using the two class method.
Earnings Per Unit of the Operating Partnership
Basic earnings per unit is calculated by dividing the net income attributable to common units for the period by the weighted average number of common units outstanding during the period using the two class method. Diluted earnings per unit is calculated by dividing the net income attributable to common units for the period by the weighted average number of common and dilutive securities outstanding during the period using the two class method.
Stock-based Compensation
We award stock-based compensation to employees and members of our Board of Directors in the form of common stock. For each stock award granted by DFT, the OP issues an equivalent common unit, which may be referred to herein as a common share, common stock, or a common unit. We estimate the fair value of the awards and recognize this value over the requisite service period. The fair value of restricted stock-based compensation is based on the market value of DFT’s common stock on the date of the grant. The fair value of options to purchase common stock is based on the Black-Scholes model. The fair value of performance units is based on a Monte Carlo simulation.
Compensation paid with Company common shares, which is included in general and administrative expense on the consolidated statements of operations, totaled $6.2 million, $6.1 million and $7.0 million for the years ended December 31, 2014, 2013 and 2012, respectively. We capitalized $0.7 million, $0.6 million and $0.4 million of compensation paid with Company common shares to our data centers under development for the years ended December 31, 2014, 2013 and 2012, respectively.
Recently Issued Accounting Pronouncements
In May 2014, the Financial Accounting Standards Board issued a comprehensive new revenue recognition standard that will supersede nearly all existing revenue recognition guidance under GAAP. The standard’s core principle is that a company will recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which the company expects to be entitled in exchange for those goods or services. We will be required to apply the new standard in the first quarter of 2017 and are assessing whether the new standard will have a material effect on our financial position or results of operations.

3_Real_Estate_Assets

3. Real Estate Assets	12 Months Ended
	Dec. 31, 2014
Real Estate [Abstract]
Real Estate Disclosure [Text Block]	Real Estate Assets
	The following is a summary of our properties as of December 31, 2014 (dollars in thousands):
	Property	Location		Land		Buildings and		Construction		Total Cost
						Improvements		in Progress
								and Land Held
								for
								Development
	ACC2	Ashburn, VA		$	2,500	$	159,158			$	161,658
	ACC3	Ashburn, VA		1,071		95,926				96,997
	ACC4	Ashburn, VA		6,600		538,551				545,151
	ACC5	Ashburn, VA		6,443		298,521				304,964
	ACC6	Ashburn, VA		5,518		216,697				222,215
	ACC7 Phase I	Ashburn, VA		2,787		92,989				95,776
	VA3	Reston, VA		9,000		178,362				187,362
	VA4	Bristow, VA		6,800		149,250				156,050
	CH1	Elk Grove Village, IL		23,611		358,412				382,023
	NJ1 Phase I	Piscataway, NJ		4,311		210,136				214,447
	SC1 Phase I and IIA	Santa Clara, CA		15,152		325,537				340,689
				83,793		2,623,539		—		2,707,332
	Construction in progress and land held for development	(1	)					358,965		358,965
				$	83,793	$	2,623,539	$	358,965	$	3,066,297
	-1	Properties located in Ashburn, VA (ACC7 Phases II-IV and ACC8); Piscataway, NJ (NJ1 Phase II), Elk Grove Village, IL (CH2) and Santa Clara, CA (SC1 Phase IIB and SC2).
	The following presents the major components of our properties and the useful lives over which they are depreciated.
	Component		Component Life (years)
	Land		N/A
	Building improvements		40
	Electrical infrastructure—power distribution units		20
	Electrical infrastructure—uninterrupted power supply		25
	Electrical infrastructure—switchgear/transformers		30
	Fire protection		40
	Security systems		20
	Mechanical infrastructure—heating, ventilating and air conditioning		20
	Mechanical infrastructure—chiller pumps/building automation		25
	Mechanical infrastructure—chilled water storage and pipes		30

4_Intangible_Assets_and_Liabil

4. Intangible Assets and Liabilities (Notes)	12 Months Ended
	Dec. 31, 2014
Intangible Assets and Liabilities [Abstract]
Intangible Assets And Liabilities [Text Block]	Intangible Assets and Liabilities
	Leasing Costs are classified as deferred costs and are amortized as amortization expense on a straight-line basis over the remaining life of the underlying leases. As of December 31, 2014, these assets have a weighted average remaining life of 6.8 years with estimated future amortization as follows (in thousands):
	Year Ending December 31,
	2015	$	4,164
	2016	3,817
	2017	3,455
	2018	2,883
	2019	1,810
	2020 and thereafter	5,076
		$	21,205
	Lease Intangible assets and liabilities are classified as lease contracts above and below market value, respectively, and amortized on a straight-line basis as decreases and increases, respectively, to rental revenue over the remaining term of the underlying leases. As of December 31, 2014, our net Lease Intangible liabilities have a weighted average remaining life of 8.2 years for above market leases and 3.2 years for below market leases with estimated net future amortization (as an increase (decrease) to rental income) as follows (in thousands):
	Year Ending December 31,
	2015	$	1,966
	2016	412
	2017	174
	2018	(72		)
	2019	(655		)
	2020 and thereafter	(2,842		)
		$	(1,017	)
	Tenant Origination Costs are included in buildings and improvements in our accompanying consolidated balance sheets and are amortized as depreciation expense on a straight-line basis over the average remaining life of the underlying leases. As of December 31, 2014, these assets have a weighted average remaining life of 3.2 years with estimated future amortization as follows (in thousands):
	Year Ending December 31,
	2015	$	2,019
	2016	1,243
	2017	1,243
	2018	747
		$	5,252

5_Leases_Notes

5. Leases (Notes)	12 Months Ended
	Dec. 31, 2014
Leases [Abstract]
Leases of Lessor Disclosure [Text Block]	Leases
	For the years ended December 31, 2014, 2013 and 2012, the following customers comprised more than 10.0% of our consolidated revenues:
		Microsoft		Facebook		Rackspace		Yahoo!
	Year ended December 31, 2014	21.6	%	17.4	%	12.4	%	10.9	%
	Year ended December 31, 2013	17.8	%	19.2	%	11.6	%	13	%
	Year ended December 31, 2012	14.9	%	20.7	%	9.3	%	15.5	%
	As of December 31, 2014, these four customers accounted for $(0.3) million, $43.6 million, $35.4 million, and $10.8 million of deferred rent and $8.3 million, $6.4 million, $0, and $3.8 million of prepaid rents, respectively. As of December 31, 2013, these four customers accounted for $5.5 million, $45.6 million, $30.4 million, and $13.5 million of deferred rent and $7.1 million, $0 million, $3.4 million, and $4.0 million of prepaid rents, respectively. We do not hold security deposits from these customers. The majority of our customers operate within the technology industry and, as such, their viability is subject to market fluctuations in that industry.
	As of December 31, 2014, future minimum lease payments to be received under noncancelable operating leases are as follows for the years ending December 31 (in thousands):
	2015	$	288,332
	2016	279,422
	2017	275,328
	2018	246,795
	2019	179,956
	2020 and thereafter	515,883
		$	1,785,716

6_Debt

6. Debt	12 Months Ended
	Dec. 31, 2014
Debt Disclosure [Abstract]
Debt Disclosure [Text Block]	Debt
	Debt Summary as of December 31, 2014 and December 31, 2013
	($ in thousands)
		December 31, 2014													December 31, 2013
		Amounts				% of Total			Rates			Maturities			Amounts
												(years)
	Secured	$	115,000			11	%		1.7	%		3.2			$	115,000
	Unsecured	910,000				89	%		4.4	%		5.9			754,000
	Total	$	1,025,000			100	%		4.1	%		5.6			$	869,000
	Fixed Rate Debt:
	Unsecured Notes due 2021	$	600,000			59	%		5.9	%		6.7			$	600,000
	Fixed Rate Debt	600,000				59	%		5.9	%		6.7			600,000
	Floating Rate Debt:
	Unsecured Credit Facility	60,000				6	%		1.7	%		3.4			—
	Unsecured Term Loan	250,000				24	%		1.7	%		4.6			154,000
	ACC3 Term Loan	115,000				11	%		1.7	%		3.2			115,000
	Floating Rate Debt	425,000				41	%		1.7	%		4			269,000
	Total	$	1,025,000			100	%		4.1	%		5.6			$	869,000
	Outstanding Indebtedness
	ACC3 Term Loan
	On March 27, 2013, we entered into a $115 million term loan facility (the “ACC3 Term Loan”). On May 9, 2014, we amended this facility to, among other things, reduce the rate at which borrowings bear interest. Per the amendment, the borrower, one of our subsidiaries, may elect to have borrowings under the facility bear interest at (i) LIBOR plus 1.55% (in lieu of the original margin of 1.85%) or (ii) a base rate, which is based on the lender's prime rate, plus 0.55% (in lieu of the original margin of 0.85%). The interest rate is currently at LIBOR plus 1.55%. The ACC3 Term Loan matures on March 27, 2018, and we may prepay the ACC3 Term Loan at any time, in whole or in part, without penalty or premium.
	The ACC3 Term Loan is secured by the ACC3 data center and an assignment of the lease agreement between us and the customer of ACC3. The Operating Partnership has guaranteed the outstanding principal amount of the ACC3 Term Loan, plus interest and certain costs under the loan.
	The ACC3 Term Loan imposes financial maintenance covenants relating to, among other things, the following matters:
	•	consolidated total indebtedness of the Operating Partnership not exceeding 60% of gross asset value of the Operating Partnership;
	•	fixed charge coverage ratio of the Operating Partnership being not less than 1.70 to 1.00;
	•	tangible net worth of the Operating Partnership being not less than $1.3 billion plus 80% of the sum of (i) net equity offering proceeds and (ii) the value of equity interests issued in connection with a contribution of assets to the Operating Partnership or its subsidiaries; and
	•	debt service coverage ratio of the borrower not less than 1.50 to 1.00.
	We were in compliance with all of the covenants under the loan as of December 31, 2014.
	Unsecured Term Loan
	On September 13, 2013, the Operating Partnership entered into a $195 million unsecured term loan facility (the "Unsecured Term Loan"). Prior to the amendment executed in July 2014, described below, the Unsecured Term Loan matured on February 15, 2019, with no extension option.
	The Unsecured Term Loan includes an accordion feature permitting an increase in the amount of the loan by up to an additional $55 million. On October 18, 2013, we exercised the accordion and the Unsecured Term Loan was increased to $250 million. As of December 31, 2013 we had drawn $154.0 million under this loan and the remaining $96.0 million was advanced on January 10, 2014.
	Prior to the amendment to the Unsecured Term Loan, we could elect to have borrowings under the loan bear interest at either LIBOR or a base rate, which is based on the lender's prime rate, in each case plus an applicable margin. Prior to our receiving an investment grade credit rating, the applicable margin added to LIBOR and the base rate was based on the table below.
					Applicable Margin
	Pricing Level		Ratio of Total Indebtedness to Gross Asset Value		LIBOR Rate Loans			Base Rate Loans
	Level 1		Less than or equal to 35%		1.75	%		0.75	%
	Level 2		Greater than 35% but less than or equal to 40%		1.9	%		0.9	%
	Level 3		Greater than 40% but less than or equal to 45%		2.05	%		1.05	%
	Level 4		Greater than 45% but less than or equal to 52.5%		2.2	%		1.2	%
	Level 5		Greater than 52.5%		2.4	%		1.4	%
	The terms of the loan also provided that, in the event we received an investment grade credit rating, borrowings under the loan would bear interest based on the table below.
					Applicable Margin
	Credit Rating Level		Credit Rating		LIBOR Rate Loans			Base Rate Loans
	Level 1		Greater than or equal to A- by S&P or A3 by Moody’s		0.95	%		0	%
	Level 2		Greater than or equal to BBB+ by S&P or Baa1 by Moody’s		1.05	%		0.05	%
	Level 3		Greater than or equal to BBB by S&P or Baa2 by Moody’s		1.2	%		0.2	%
	Level 4		Greater than or equal to BBB- by S&P or Baa3 by Moody’s		1.5	%		0.5	%
	Level 5		Less than BBB- by S&P or Baa3 by Moody’s		1.95	%		0.95	%
	In July 2014, we executed an amendment to our Unsecured Term Loan that reduced the interest rate and extended the maturity date to July 21, 2019. Because the composition of lenders comprising our bank group changed in conjunction with executing the amendment, we incurred a loss on early extinguishment of debt of $1.4 million, which included a partial write-off of unamortized deferred financing costs of $0.7 million.
	Under the terms of the amendment to our Unsecured Term Loan, we may elect to have borrowings under the loan bear interest at either LIBOR or a base rate, which is based on the lender's prime rate, in each case plus an applicable margin. Prior to our receiving an investment grade credit rating, the applicable margin added to LIBOR and the base rate is based on the table below.
					Applicable Margin
	Pricing Level		Ratio of Total Indebtedness to Gross Asset Value		LIBOR Rate Loans			Base Rate Loans
	Level 1		Less than or equal to 35%		1.5	%		0.5	%
	Level 2		Greater than 35% but less than or equal to 40%		1.6	%		0.6	%
	Level 3		Greater than 40% but less than or equal to 45%		1.75	%		0.75	%
	Level 4		Greater than 45% but less than or equal to 52.5%		1.9	%		0.9	%
	Level 5		Greater than 52.5%		2.1	%		1.1	%
	The applicable margin is currently set at pricing level 1. The terms of the amendment also provide that, in the event we receive an investment grade credit rating, borrowings under the loan will bear interest based on the table below.
					Applicable Margin
	Credit Rating Level		Credit Rating		LIBOR Rate Loans			Base Rate Loans
	Level 1		Greater than or equal to A- by S&P or A3 by Moody’s		0.825	%		0	%
	Level 2		Greater than or equal to BBB+ by S&P or Baa1 by Moody’s		0.875	%		0	%
	Level 3		Greater than or equal to BBB by S&P or Baa2 by Moody’s		1	%		0	%
	Level 4		Greater than or equal to BBB- by S&P or Baa3 by Moody’s		1.25	%		0.25	%
	Level 5		Less than BBB- by S&P or Baa3 by Moody’s		1.65	%		0.65	%
Following the receipt of such investment grade rating, the terms of the loan provide for the adjustment of the applicable margin from time to time according to the rating then in effect.
The Unsecured Term Loan is unconditionally guaranteed jointly and severally, on a senior unsecured basis by DFT and the direct and indirect subsidiaries of DFT that guaranty the obligations of the Unsecured Credit Facility (as defined below).
The Unsecured Term Loan requires that we comply with various covenants that are substantially the same as those applicable under the Unsecured Credit Facility, including with respect to restrictions on liens, incurring indebtedness, making investments, effecting mergers and/or asset sales, and certain restrictions on dividend payments. In addition, the Unsecured Term Loan imposes financial maintenance covenants substantially the same as those under the Unsecured Credit Facility relating to, among other things, the following matters:
•	unsecured debt not exceeding 60% of the value of unencumbered assets;
•	net operating income generated from unencumbered properties divided by the amount of unsecured debt being not less than 12.5%;
•	total indebtedness not exceeding 60% of gross asset value;
•	fixed charge coverage ratio being not less than 1.70 to 1.00; and
•	tangible net worth being not less than $1.3 billion plus 80% of the sum of (i) net equity offering proceeds after March 21, 2012 and (ii) the value of equity interests issued in connection with a contribution of assets to the Operating Partnership or its subsidiaries after March 21, 2012.
The Unsecured Term Loan includes customary events of default, the occurrence of which, following any applicable cure period, would permit the lenders to, among other things, declare the principal, accrued interest and other obligations under the loan to be immediately due and payable.
We were in compliance with all of the covenants under the loan as of December 31, 2014.
Unsecured Notes due 2021
On September 24, 2013, the Operating Partnership completed the sale of $600 million of 5.875% unsecured notes due 2021 (the "Unsecured Notes due 2021"). The Unsecured Notes due 2021 were issued at face value and mature on September 15, 2021. We pay interest on the Unsecured Notes due 2021 semi-annually, in arrears, on March 15th and September 15th of each year.
The Unsecured Notes due 2021 are unconditionally guaranteed, jointly and severally on a senior unsecured basis by DFT and certain of the Operating Partnership’s subsidiaries, including the subsidiaries that own the ACC2, ACC4, ACC5, ACC6, VA3, VA4, CH1, NJ1 and SC1 data centers and the SC2 land (collectively, the “Subsidiary Guarantors”), but excluding the subsidiaries that own the ACC3 and ACC7 data center facilities, the CH2 data center under development, the ACC8 land, our taxable REIT subsidiary, DF Technical Services, LLC and our property management subsidiary, DF Property Management LLC.
The Unsecured Notes due 2021 rank (i) equally in right of payment with all of the Operating Partnership's existing and future senior unsecured indebtedness, (ii) senior in right of payment with all of its existing and future subordinated indebtedness, (iii) effectively subordinate to any of the Operating Partnership's existing and future secured indebtedness and (iv) effectively junior to any liabilities of any subsidiaries of the Operating Partnership that do not guarantee the Unsecured Notes due 2021. The guarantees of the Unsecured Notes due 2021 by DFT and the Subsidiary Guarantors rank (i) equally in right of payment with such guarantor's existing and future senior unsecured indebtedness, (ii) senior in right of payment with all of such guarantor's existing and future subordinated indebtedness and (iii) effectively subordinate to any of such guarantor's existing and future secured indebtedness.
At any time prior to September 15, 2016, the Operating Partnership may redeem the Unsecured Notes due 2021, in whole or in part, at a price equal to the sum of (i) 100% of the principal amount of the Unsecured Notes due 2021 to be redeemed, plus (ii) a make-whole premium and accrued and unpaid interest. The Unsecured Notes due 2021 may be redeemed at the Operating Partnership's option, in whole or in part, at any time, on and after September 15, 2016 at the following redemption prices (expressed as percentages of the principal amount thereof) if redeemed during the 12-month period commencing September 15 of the years indicated below, in each case together with accrued and unpaid interest to the date of redemption:
Year	Redemption Price
2016	104.406	%
2017	102.938	%
2018	101.469	%
2019 and thereafter	100	%
If there is a change of control (as defined in the indenture governing the Unsecured Notes due 2021) of the Operating Partnership or DFT, we must offer to purchase the Unsecured Notes due 2021 at a price equal to 101% of the principal amount thereof, plus accrued and unpaid interest. In addition, in certain circumstances we may be required to use the net proceeds of asset sales to purchase a portion of the Unsecured Notes due 2021 at 100% of the principal amount thereof, plus accrued and unpaid interest.
The Unsecured Notes due 2021 have certain covenants limiting or prohibiting the ability of the Operating Partnership and certain of its subsidiaries from, among other things, (i) incurring secured or unsecured indebtedness, (ii) entering into sale and leaseback transactions, (iii) making certain dividend payments, distributions, purchases of DFT's common stock and investments, (iv) entering into transactions with affiliates, (v) entering into agreements limiting the ability to make certain transfers and other payments from subsidiaries, (vi) engaging in sales of assets or (vii) engaging in certain mergers, consolidations or transfers/sales of all or substantially all assets. However, DFT may pay the minimum dividend necessary to meet its REIT income distribution requirements.
The Unsecured Notes due 2021 also require the Operating Partnership and the Subsidiary Guarantors to maintain total unencumbered assets of at least 150% of their unsecured debt on a consolidated basis. The Unsecured Notes due 2021 also have customary events of default, including, but not limited to, nonpayment, breach of covenants, and payment or acceleration defaults in certain other indebtedness of ours or certain of our subsidiaries. Upon an event of default, the holders of the Unsecured Notes due 2021 or the trustee may declare the Unsecured Notes due 2021 due and immediately payable. We were in compliance with all covenants under the Unsecured Notes due 2021 as of December 31, 2014.
Unsecured Credit Facility
On May 13, 2014, we executed the fifth amendment to our unsecured revolving credit facility ("Unsecured Credit
Facility"), resulting in an increase in total commitment from $400 million to $560 million and a reduction of the rate at which borrowings bear interest. Prior to the fifth amendment, the maturity date of the Unsecured Credit Facility was March 21, 2016 and included a one-year extension option, subject to the payment of an extension fee equal to 25 basis points on the total commitment in effect on the maturity date and certain other customary conditions. The facility also included an option to increase the total commitment to $600 million, if one or more lenders commit to being a lender for the additional amount and certain other customary conditions are met.
Prior to the fifth amendment, we could elect to have borrowings under the facility bear interest at either LIBOR or a base rate, which is based on the lender's prime rate, in each case plus an applicable margin. Prior to our receiving an investment grade credit rating, the applicable margin added to LIBOR and the base rate was based on the table below.
				Applicable Margin
Pricing Level		Ratio of Total Indebtedness to Gross Asset Value		LIBOR Rate Loans			Base Rate Loans
Level 1		Less than or equal to 35%		1.85	%		0.85	%
Level 2		Greater than 35% but less than or equal to 40%		2	%		1	%
Level 3		Greater than 40% but less than or equal to 45%		2.15	%		1.15	%
Level 4		Greater than 45% but less than or equal to 52.5%		2.3	%		1.3	%
Level 5		Greater than 52.5%		2.5	%		1.5	%
The terms of the facility also provided that, in the event we receive an investment grade credit rating, borrowings under the facility would bear interest based on the table below.
				Applicable Margin
Credit Rating Level		Credit Rating		LIBOR Rate Loans			Base Rate Loans
Level 1		Greater than or equal to A- by S&P or A3 by Moody’s		1.05	%		0.05	%
Level 2		Greater than or equal to BBB+ by S&P or Baa1 by Moody’s		1.2	%		0.2	%
Level 3		Greater than or equal to BBB by S&P or Baa2 by Moody’s		1.35	%		0.35	%
Level 4		Greater than or equal to BBB- by S&P or Baa3 by Moody’s		1.5	%		0.5	%
Level 5		Less than BBB- by S&P or Baa3 by Moody’s		2.1	%		1.1	%
The fifth amendment provided us with the ability to, at our option, increase the total commitment under the facility to
$800 million, if one or more lenders commit to being a lender for the additional amount and certain other customary conditions are met. The amendment also extended the maturity date to May 13, 2018, with a one-year extension option, subject to the payment of an extension fee equal to 15 basis points on the total commitment in effect on such initial maturity date and certain other customary conditions. Because the composition of lenders comprising our bank group changed in conjunction with executing the amendment, we incurred a partial write-off of unamortized deferred financing costs related to the Unsecured Credit Facility totaling $0.3 million.
Under the terms of the amended facility, we may elect to have borrowings under the facility bear interest at either LIBOR or a base rate, which is based on the lender's prime rate, in each case plus an applicable margin. Prior to our receiving an investment grade credit rating, the applicable margin added to LIBOR and the base rate is based on the table below.
				Applicable Margin
Pricing Level		Ratio of Total Indebtedness to Gross Asset Value		LIBOR Rate Loans			Base Rate Loans
Level 1		Less than or equal to 35%		1.55	%		0.55	%
Level 2		Greater than 35% but less than or equal to 40%		1.65	%		0.65	%
Level 3		Greater than 40% but less than or equal to 45%		1.8	%		0.8	%
Level 4		Greater than 45% but less than or equal to 52.5%		1.95	%		0.95	%
Level 5		Greater than 52.5%		2.15	%		1.15	%
The applicable margin is currently set at pricing level 1. The terms of the facility provide for the adjustment of the applicable margin from time to time according to the ratio of the Operating Partnership’s total indebtedness to gross asset value in effect from time to time.
The terms of the amended facility also provide that, in the event we receive an investment grade credit rating, borrowings under the facility will bear interest based on the table below.
				Applicable Margin
Credit Rating Level		Credit Rating		LIBOR Rate Loans			Base Rate Loans
Level 1		Greater than or equal to A- by S&P or A3 by Moody’s		0.875	%		0	%
Level 2		Greater than or equal to BBB+ by S&P or Baa1 by Moody’s		0.925	%		0	%
Level 3		Greater than or equal to BBB by S&P or Baa2 by Moody’s		1.05	%		0.05	%
Level 4		Greater than or equal to BBB- by S&P or Baa3 by Moody’s		1.3	%		0.3	%
Level 5		Less than BBB- by S&P or Baa3 by Moody’s		1.7	%		0.7	%
Following the receipt of such investment grade rating, the terms of the facility provide for the adjustment of the applicable margin from time to time according to the rating then in effect.
The facility is unconditionally guaranteed, jointly and severally, on a senior unsecured basis by DFT and all of the Operating Partnership’s subsidiaries that currently guaranty the obligations under the Unsecured Notes due 2021, listed above.
The amount available for borrowings under the facility is determined according to a calculation comparing the value of certain unencumbered properties designated by the Operating Partnership at such time relative to the amount of the Operating Partnership's unsecured debt. Up to $35 million of the borrowings under the facility may be used for letters of credit.
As of December 31, 2014, a letter of credit totaling less than $0.1 million was outstanding under the facility. As of December 31, 2014, $60.0 million of borrowings were outstanding under this facility. As of February 25, 2015, $120.0 million of borrowings were outstanding under this facility.
The facility requires that DFT, the Operating Partnership and their subsidiaries comply with various covenants, including with respect to restrictions on liens, incurring indebtedness, making investments, effecting mergers and/or asset sales, and certain limits on dividend payments, distributions and purchases of DFT's stock. In addition, the facility imposes financial maintenance covenants relating to, among other things, the following matters:
•	unsecured debt not exceeding 60% of the value of unencumbered assets;
•	net operating income generated from unencumbered properties divided by the amount of unsecured debt being not less than 12.5%;
•	total indebtedness not exceeding 60% of gross asset value;
•	fixed charge coverage ratio being not less than 1.70 to 1.00; and
•	tangible net worth being not less than $1.3 billion plus 80% of the sum of (i) net equity offering proceeds after March 21, 2012 and (ii) the value of equity interests issued in connection with a contribution of assets to the Operating Partnership or its subsidiaries.
The facility includes customary events of default, the occurrence of which, following any applicable cure period, would permit the lenders to, among other things, declare the principal, accrued interest and other obligations of the Operating Partnership under the facility to be immediately due and payable. We were in compliance with all covenants under the facility as of December 31, 2014.
A summary of the Company's debt maturity schedule as of December 31, 2014 is as follows:
Debt Maturity as of December 31, 2014
($ in thousands)
Year		Fixed Rate					Floating Rate					Total				% of Total		Rates
2015		$	—				—					$	—			—		—
2016		—					3,750			-2		3,750				0.4	%	1.7	%
2017		—					8,750			-2		8,750				0.8	%	1.7	%
2018		—					162,500			(2)(3)		162,500				15.9	%	1.7	%
2019		—					250,000			-4		250,000				24.4	%	1.7	%
2020		—					—					—				—		—
2021		600,000			-1		—					600,000				58.5	%	5.9	%
Total		$	600,000				$	425,000				$	1,025,000			100	%	4.1	%
-1	The 5.875% Unsecured Notes due 2021 mature on September 15, 2021.
-2	The ACC3 Term Loan matures on March 27, 2018 with no extension option. Quarterly principal payments of $1.25 million begin on April 1, 2016, increase to $2.5 million on April 1, 2017 and continue through maturity.
-3	The Unsecured Credit Facility matures on May 13, 2018 with a one-year extension option.
-4	The Unsecured Term Loan matures on July 21, 2019 with no extension option.

7_Related_Party_Transactions_N

7. Related Party Transactions (Notes)	12 Months Ended
	Dec. 31, 2014
Related Party Transactions Disclosure [Text Block]	Related Party Transactions
	For the years ended December 31, 2014, 2013 and 2012, we incurred $0.1 million, $0.3 million and $0.2 million of cost, respectively, to charter an aircraft for business travel that is owned by our former President and Chief Executive Officer. For the years ended December 31, 2014, 2013 and 2012, we incurred $0, $0.1 million and $0.5 million of expenses for personal travel of our former President and Chief Executive Officer in lieu of the former Chief Executive Officer’s annual salary under the terms of his employment agreement. Effective February 5, 2013, we no longer reimbursed the Chief Executive Officer for personal travel in lieu of salary.
	We lease space for our headquarters building from an affiliate of the Chairman of the Board and the former President and Chief Executive Officer. Rent expense was $0.4 million for each of the years ended December 31, 2014, 2013 and 2012.
	In February 2015, we entered into two purchase agreements under which we will acquire two parcels of undeveloped land in Ashburn, Virginia, from entities controlled by Lammot J. du Pont, our Chairman of the Board, and Hossein Fateh, our Vice Chairman of the Board.
	One agreement relates to a 34.8 acre site that is adjacent to the Ashburn Corporate Center, where our ACC2, ACC3, ACC4, ACC5, ACC6 and ACC7 data center facilities are located, for a total of $15.5 million. The sole managers of the entity that owns this site are a limited liability company owned solely by Mr. du Pont, which also owns approximately 7% of the seller, and a limited liability company owned solely by Mr. Fateh, which also owns approximately 1% of the seller.
	The other agreement relates to an 8.7 acre site that is part of the Ashburn Corporate Center and adjacent to our ACC4 and ACC7 data center facilities for a total of $4.6 million. Mssrs. du Pont and Fateh are the sole managers of the limited liability company that manages the entity that owns this site. Mr. du Pont directly and indirectly owns approximately 23% of the seller, and Mr. Fateh directly and indirectly owns approximately 18% of the seller. In addition, Frederic V. Malek, one of our independent directors, is a non-managing member of the entity that owns this site. Mr. Malek’s sole interest in this entity is the ownership of an approximately 4% non-managing membership interest; he is neither an employee nor an executive officer of this entity. The purchase price for each site was based on an appraisal prepared by an independent appraisal firm.

8_Commitments_and_Contingencie

8. Commitments and Contingencies	12 Months Ended
	Dec. 31, 2014
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies Disclosure [Text Block]	Commitments and Contingencies
	We are involved from time to time in various legal proceedings, lawsuits, examinations by various tax authorities and claims that have arisen in the ordinary course of business. We currently believe that the resolution of such matters will not have a material adverse effect on our financial condition or results of operations.
	Contracts related to the development of the SC1 Phase IIB and CH2 Phase I data centers were in place as of December 31, 2014. These contracts are cost plus in nature whereby the contract sum is the aggregate cost of the actual work performed and equipment purchased plus a contractor fee. Control estimates, which are adjusted from time to time to reflect any contract changes, are estimates of the total contract cost at completion. As of December 31, 2014 the SC1 Phase IIB control estimate was $55.2 million of which $43.0 million had been incurred. An additional $3.6 million has been committed under this contract as of December 31, 2014. As of December 31, 2014, the CH2 Phase I control estimate was $168.9 million of which $91.7 million has been incurred. An additional $36.8 million has been committed under this contract as of December 31, 2014.
	In February 2015, we entered into two purchase agreements under which we will acquire two parcels of undeveloped land in Ashburn, Virginia. One agreement relates to a 34.8 acre site that is adjacent to the Ashburn Corporate Center, where our ACC2, ACC3, ACC4, ACC5, ACC6 and ACC7 data center facilities are located, for a total of $15.5 million. The other agreement relates to an 8.7 acre site that is part of the Ashburn Corporate Center and adjacent to our ACC4 and ACC7 data center facilities for a total of $4.6 million (see Note 7).
	Concurrent with DFT’s October 2007 initial public offering, we entered into tax protection agreements with some of the contributors of the initial properties including DFT’s Chairman of the Board and President and CEO. Pursuant to the terms of these agreements, if we dispose of any interest in the initial contributed properties that generates more than a certain allowable amount of built-in gain for the contributors, as a group, in any single year through 2017, we will indemnify the contributors for a portion of the tax liabilities incurred with respect to the amount of built-in gain and tax liabilities incurred as a result of the reimbursement payment. The amount of initial built-in gain that can be recognized as of January 1, 2015 without triggering the tax protection provisions is approximately 80% of the initial built in gain of $667 million (unaudited) or $534 million (unaudited). This percentage increases each year by 10%, accumulating to 100% in 2017. As of December 31, 2014, none of the tax protection provisions have been triggered and no liability has been recorded on our consolidated balance sheet. If, as of January 1, 2015, the tax protection provisions were triggered, we could be liable for protection on the taxes related to up to approximately $12 million (unaudited) of built-in gain. Additionally, pursuant to the terms of these agreements, we must provide an opportunity for certain of the contributors of the initial properties to guarantee a secured loan and, if we fail to do so, we could be liable for protection on the taxes related to approximately $97 million (unaudited) of remaining minimum liability. The amount of our liability for protection on taxes could be based on the highest federal, state and local capital gains tax rates of the applicable contributor. Any sale by the Company that requires payments to any of DFT’s executive officers or directors pursuant to these agreements requires the approval of at least 75% of the disinterested members of DFT’s Board of Directors.

9_Redeemable_noncontrolling_in

9. Redeemable noncontrolling interests operating partnership / Redeemable partnership units	12 Months Ended
	Dec. 31, 2014
Redeemable noncontrolling interests – operating partnership / Redeemable partnership units [Abstract]
Redeemable noncontrolling interests – operating partnership / Redeemable partnership units [Text Block]	Redeemable noncontrolling interests – operating partnership / Redeemable partnership units
	Redeemable noncontrolling interests – operating partnership, as presented in DFT’s accompanying consolidated balance sheets, represent the OP units held by individuals and entities other than DFT. These interests are also presented in the Operating Partnership’s consolidated balance sheets, referred to as “redeemable partnership units.” Accordingly, the following discussion related to redeemable noncontrolling interests – operating partnership of DFT refers equally to redeemable partnership units of the Operating Partnership.
	The redemption value of redeemable noncontrolling interests – operating partnership as of December 31, 2014 and December 31, 2013 was $513.1 million and $387.2 million, respectively, based on the closing share price of DFT’s common stock of $33.24 and $24.71, respectively, on those dates.
	Holders of OP units are entitled to receive distributions in a per unit amount equal to the per share dividends made with respect to each share of DFT’s common stock, if and when DFT’s Board of Directors declares such a dividend. Holders of OP units have the right to tender their units for redemption, in an amount equal to the fair market value of DFT’s common stock. DFT may elect to redeem tendered OP units for cash or for shares of DFT’s common stock. During the years ended December 31, 2014, 2013 and 2012 OP unitholders redeemed a total of 234,300, 3,115,269, and 277,575 OP units in exchange for an equal number of shares of common stock. See Note 2.

10_Preferred_Stock

10. Preferred Stock	12 Months Ended
	Dec. 31, 2014
Preferred Stock [Abstract]
Preferred Stock [Text Block]	Preferred Stock
	Series A Preferred Stock
	In October 2010, DFT issued 7,400,000 shares of 7.875% Series A Cumulative Redeemable Perpetual Preferred Stock (“Series A Preferred Stock”) for $185.0 million in an underwritten public offering. The liquidation preference on the Series A Preferred Stock is $25 per share and dividends are scheduled quarterly. For each share of Series A Preferred Stock issued by DFT, the Operating Partnership issued a preferred unit equivalent to DFT with the same terms.
	For the year ended December 31, 2014, DFT declared and paid the following cash dividends on its Series A Preferred Stock, of which the OP paid equivalent distributions on its preferred units:
	Record Date	Payment Date	Cash Dividend		Ordinary Taxable Dividend (Unaudited)		Nontaxable Return of Capital Distributions (Unaudited)
	4/4/14	4/15/14	$	0.4921875	$	0.4921875	$	0
	7/3/14	7/15/14	0.4921875		0.4921875		0
	10/3/14	10/15/14	0.4921875		0.4921875		0
	12/30/14	1/15/15	0.4921875		0.4921875		0
			$	1.96875	$	1.96875	$	0
	For the year ended December 31, 2013, DFT declared and paid the following cash dividends on its Series A Preferred Stock, of which the OP paid equivalent distributions on its preferred units:
	Record Date	Payment Date	Cash Dividend		Ordinary Taxable Dividend (Unaudited)		Nontaxable Return of Capital Distributions (Unaudited)
	4/5/13	4/15/13	$	0.4921875	$	0.4921875	$	0
	7/5/13	7/15/13	0.4921875		0.4921875		0
	10/4/13	10/15/13	0.4921875		0.4921875		0
	12/27/13	1/15/14	0.4921875		0.4921875		0
			$	1.96875	$	1.96875	$	0
	For the year ended December 31, 2012, DFT declared and paid the following cash dividends on its Series A Preferred Stock, of which the OP paid equivalent distributions on its preferred units:
	Record Date	Payment Date	Cash Dividend		Ordinary Taxable Dividend (Unaudited)		Nontaxable Return of Capital Distributions (Unaudited)
	4/5/12	4/16/12	$	0.4921875	$	0.4921875	$	0
	7/6/12	7/16/12	0.4921875		0.4921875		0
	10/5/12	10/15/12	0.4921875		0.4921875		0
	12/28/12	1/15/13	0.4921875		0.4921875		0
			$	1.96875	$	1.96875	$	0
	Except in instances relating to preservation of DFT's qualification as a REIT or pursuant to the special optional redemption right discussed below, the Series A Preferred Stock is not redeemable prior to October 15, 2015. On and after October 15, 2015, we may, at our 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 per share, plus any accrued and unpaid dividends to, but not including, the date of
	redemption.
	If, at any time following a change of control, the Series A Preferred Stock is not listed on the NYSE or quoted on NASDAQ (or listed or quoted on a successor exchange or quotation system), holders will be entitled to receive dividends at an increased rate of 11.875%, and we will have the option to redeem the Series A Preferred Stock, in whole but not in part, within 90 days after the first date on which both the change of control has occurred and the Series A Preferred Stock is not so listed or quoted, for cash at $25 per share, plus accrued and unpaid dividends (whether or not declared) to, but not including, the redemption date.
	Series B Preferred Stock
	In March 2011 and January 2012, DFT issued an aggregate of 6,650,000 shares of 7.625% Series B Cumulative Redeemable Perpetual Preferred Stock (“Series B Preferred Stock”) for $166.3 million in underwritten public offerings. The liquidation preference on the Series B Preferred Stock is $25 per share and dividends are scheduled quarterly. For each share of Series B Preferred Stock issued by DFT, the Operating Partnership issued a preferred unit equivalent to DFT with the same terms.
	For the year ended December 31, 2014, DFT declared and paid the following cash dividends on its Series B Preferred Stock, of which the OP paid equivalent distributions on its preferred units:
	Record Date	Payment Date	Cash Dividend		Ordinary Taxable Dividend (Unaudited)		Nontaxable Return of Capital Distributions (Unaudited)
	4/4/14	4/15/14	$	0.4765625	$	0.4765625	$	0
	7/3/14	7/15/14	0.4765625		0.4765625		0
	10/3/14	10/15/14	0.4765625		0.4765625		0
	12/30/14	1/15/15	0.4765625		0.4765625		0
			$	1.90625	$	1.90625	$	0
	For the year ended December 31, 2013, DFT declared and paid the following cash dividends on its Series B Preferred Stock, of which the OP paid equivalent distributions on its preferred units:
	Record Date	Payment Date	Cash Dividend		Ordinary Taxable Dividend (Unaudited)		Nontaxable Return of Capital Distributions (Unaudited)
	4/5/13	4/15/13	$	0.4765625	$	0.4765625	$	0
	7/5/13	7/15/13	0.4765625		0.4765625		0
	10/4/13	10/15/13	0.4765625		0.4765625		0
	12/27/13	1/15/14	0.4765625		0.4765625		0
			$	1.90625	$	1.90625	$	0
	For the year ended December 31, 2012, DFT declared and paid the following cash dividends on its Series B Preferred Stock, of which the OP paid equivalent distributions on its preferred units:
	Record Date	Payment Date	Cash Dividend		Ordinary Taxable Dividend (Unaudited)		Nontaxable Return of Capital Distributions (Unaudited)
	4/5/12	4/16/12	$	0.4765625	$	0.4765625	$	0
	7/6/12	7/16/12	0.4765625		0.4765625		0
	10/5/12	10/15/12	0.4765625		0.4765625		0
	12/28/12	1/15/13	0.4765625		0.4765625		0
			$	1.90625	$	1.90625	$	0
	Except in instances relating to preservation of DFT's qualification as a REIT or pursuant to the special optional redemption right and conversion right discussed below, the Series B Preferred Stock is not redeemable prior to March 15, 2016 or convertible at any time. On and after March 15, 2016, we may, at our option, redeem the Series B Preferred Stock, in whole, at any time, or in part, from time to time, for cash at a redemption price of $25 per share, plus any accrued and unpaid dividends to, but not including, the date of redemption.
	Upon the occurrence of a change of control, we have a special optional redemption right that enables us to redeem the Series B Preferred Stock within 120 days after the first date on which a change of control has occurred resulting in neither DFT nor the surviving entity having a class of common shares listed on the NYSE, NYSE Amex or NASDAQ. For this special redemption right, the redemption price is $25 per share in cash, plus accrued and unpaid dividends (whether or not declared) to, but not including, the redemption date.
	Upon the occurrence of a change of control that results in neither DFT nor the surviving entity having a class of common shares listed on the NYSE, NYSE Amex or NASDAQ, the holder will have the right (subject to our special optional redemption right to redeem the Series B Preferred Stock) to convert some or all of the Series B Preferred Stock into a number of shares of DFT's common stock equal to the lesser of (A) the quotient obtained by dividing (i) the sum of (x) $25.00, plus (y) an amount equal to any accrued and unpaid dividends, whether or not declared, to but not including, the date of conversion (unless the date of conversion is after a record date for a Series B Preferred Stock dividend payment and prior to the corresponding Series B Preferred Stock dividend payment date, in which case no additional amount for such accrued and unpaid dividend will be included in this quotient), by (ii) the price of DFT's common stock, and (B) 2.105 (the Share Cap), subject to certain adjustments and provisions for the receipt of alternative consideration of equivalent value.

11_Stockholders_Equity_of_the_

11. Stockholders Equity of the REIT and Partners Capital of the OP	12 Months Ended
	Dec. 31, 2014
Stockholders’ Equity of the REIT and Partners’ Capital of the OP [Abstract]
Stockholders' Equity Of The REIT And Partners' Capital Of The OP [Text Block]	Stockholders’ Equity of DFT and Partners’ Capital of the OP
	During the years ended December 31, 2014, 2013 and 2012:
	•	DFT issued an aggregate of 163,187, 216,209 and 157,025 shares of common stock in connection with our annual grant of restricted stock to employees, the hiring of new employees and grants and retainers for our Board of Directors. The OP issued an equivalent number of units to the REIT.
	•	OP unitholders redeemed a total of 234,300, 3,115,269 and 277,575 OP units in exchange for an equal number of shares of DFT’s common stock.
	For the year ended December 31, 2014, DFT declared and paid the following cash dividends totaling $1.47 per share on its common stock, of which the OP paid equivalent distributions on OP units:
	Record Date		Payment Date	Cash Dividend		Ordinary Taxable Dividend (Unaudited)		Nontaxable Return of Capital Distributions (Unaudited)
	4/4/14		4/15/14	$	0.35	$	0.35	$	0
	7/3/14		7/15/14	0.35		0.35		0
	10/3/14		10/15/14	0.35		0.35		0
	12/30/14		1/15/15	0.42		0.39		0
				$	1.47	$	1.44	$	0
	Of the $0.42 dividend paid in January 2015, $0.03 (unaudited) will be included in 2015 taxable common dividends.
	For the year ended December 31, 2013, DFT declared and paid the following cash dividends totaling $0.95 per share on its common stock, of which the OP paid equivalent distributions on OP units:
	Record Date		Payment Date	Cash Dividend		Ordinary Taxable Dividend (Unaudited)		Nontaxable Return of Capital Distributions (Unaudited)
	4/5/13		4/15/13	$	0.2	$	0.172	$	0.028
	7/5/13		7/15/13	0.25		0.214		0.036
	10/4/13		10/15/13	0.25		0.214		0.036
	12/27/13		1/15/14	0.25		0		0
				$	0.95	$	0.6	$	0.1
	Of the $0.25 dividend paid in January 2014, $0.25 (unaudited) was included in 2014 taxable common dividends.
	For the year ended December 31, 2012, DFT declared and paid the following cash dividends totaling $0.62 per share on its common stock, of which the OP paid equivalent distributions on OP units:
	Record Date		Payment Date	Cash Dividend		Ordinary Taxable Dividend (Unaudited)		Nontaxable Return of Capital Distributions (Unaudited)
	4/5/12		4/16/12	$	0.12	$	0.12	$	0
	7/6/12		7/16/12	0.15		0.15		0
	10/5/12		10/15/12	0.15		0.15		0
	12/28/12		1/15/13	0.2		0.15		0
				$	0.62	$	0.57	$	0
	Of the $0.20 dividend paid in January 2013, $0.05 (unaudited) was included in 2013 taxable common dividends.
	In November 2012, the Board of Directors authorized a repurchase program to acquire up to $80.0 million of DFT's common shares. During the year ended December 31, 2013, DFT repurchased 1,632,673 shares of its common stock, totaling $37.8 million. All repurchased shares were retired immediately. This program expired on December 31, 2013.
	In September 2013, the Board of Directors approved a common stock repurchase program to acquire up to $122.2 million of DFT's common shares. Under this program, which expired on December 31, 2014, DFT repurchased none of its common stock.
	In December 2014, the Board of Directors approved a new common stock repurchase program to acquire up to $120.0 million of DFT's common shares in 2015.

12_Equity_Compensation_Plan

12. Equity Compensation Plan	12 Months Ended
	Dec. 31, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Disclosure of Compensation Related Costs, Share-based Payments [Text Block]	Equity Compensation Plan
	In May 2011, our Board of Directors adopted the 2011 Equity Incentive Plan (the “2011 Plan”) following approval from our stockholders. The 2011 Plan is administered by the Compensation Committee of our Board of Directors. The 2011 Plan allows us to provide equity-based compensation to our personnel and directors in the form of stock options, stock appreciation rights, dividend equivalent rights, restricted stock, restricted stock units, performance-based awards, unrestricted stock, long term incentive units (“LTIP units”) and other awards.
	The 2011 Plan authorizes a maximum aggregate of 6,300,000 share equivalents be reserved for future issuances. In addition, shares that were awarded under our 2007 Equity Compensation Plan (the “2007 Plan”) that subsequently become available due to forfeitures of such awards are available for issuance under the 2011 Plan.
	The 2011 Plan provides that awards can no longer be made under the 2007 Plan. Furthermore, under the 2011 Plan, shares of common stock that are subject to awards of options or stock appreciation rights will be counted against the 2011 Plan share limit as one share for every one share subject to the award. Any shares of stock that are subject to awards other than options or stock appreciation rights shall be counted against the 2011 Plan share limit as 2.36 shares for every one share subject to the award.
	As of December 31, 2014, 2,203,970 share equivalents were issued under the 2011 Plan, and the maximum aggregate amount of share equivalents remaining available for future issuance was 4,096,030.
	Restricted Stock
	Restricted stock awards vest over specified periods of time as long as the employee remains employed with the Company. The following table sets forth the number of unvested shares of restricted stock and the weighted average fair value of these shares at the date of grant:
		Shares of			Weighted Average
		Restricted Stock			Fair Value at
					Date of Grant
	Unvested balance at December 31, 2011	489,329			$	15.31
	Granted	143,191			$	22.66
	Vested	(314,571	)		$	11.6
	Forfeited	(20,030	)		$	22.38
	Unvested balance at December 31, 2012	297,919			$	22.31
	Granted	203,241			$	22.82
	Vested	(162,353	)		$	21.73
	Forfeited	(34,843	)		$	22.86
	Unvested balance at December 31, 2013	303,964			$	22.89
	Granted	149,608			$	25.63
	Vested	(125,798	)		$	23.02
	Forfeited	(3,785	)		$	23.98
	Unvested balance at December 31, 2014	323,989			$	24.1
	During the years ended December 31, 2014, 2013 and 2012, we issued 149,608, 203,241 and 143,191 shares of restricted stock, which had an aggregate value of $3.8 million, $4.6 million and $3.2 million, on the respective grant dates. These amounts will be amortized to expense over the respective vesting periods, which are typically three years. Also during the years ended December 31, 2014, 2013 and 2012, 125,798, 162,353 and 314,571 shares of restricted stock vested, respectively, at an intrinsic value of $3.4 million, $3.8 million and $7.2 million on their respective vesting dates.
	As of December 31, 2014, total unearned compensation on restricted stock was $5.0 million, and the weighted average vesting period was 1.1 years.
	Stock Options
	Stock option awards are granted with an exercise price equal to the closing market price of DFT’s common stock at the date of grant and vest over specified periods of time as long as the employee remains employed with the Company. All shares to be issued upon option exercises will be newly issued shares and the options have 10-year contractual terms. During the year ended December 31, 2014, no options were granted to employees.
	A summary of our stock option activity under the applicable equity incentive plan for the years ended December 31, 2014, 2013 and 2012 is presented in the tables below.
		Number of			Weighted Average
		Options			Exercise Price
	Under option, December 31, 2011	1,902,843			$	13.6
	Granted	341,541			$	22.57
	Exercised	(113,955	)		$	7.62
	Forfeited	(53,648	)		$	22.6
	Under option, December 31, 2012	2,076,781			$	15.17
	Granted	374,214			$	22.62
	Exercised	(250,472	)		$	6.83
	Forfeited	(100,613	)		$	22.83
	Under option, December 31, 2013	2,099,910			$	17.13
	Granted	—			$	—
	Exercised	(507,056	)		$	10.95
	Forfeited	—			$	—
	Under option, December 31, 2014	1,592,854			$	19.09
		Shares Subject			Total Unearned				Weighted Average		Weighted Average
		to Option			Compensation				Vesting Period		Remaining
											Contractual Term
	As of December 31, 2012	2,076,781			$	3.2	million		0.8 years		7.3 years
	As of December 31, 2013	2,099,910			$	1.9	million		0.8 years		6.9 years
	As of December 31, 2014	1,592,854			$	0.7	million		0.5 years		6.2 years
	The following table sets forth the number of unvested options as of December 31, 2014, 2013 and 2012 and the weighted average fair value of these options at the grant date.
		Number of			Weighted Average
		Options			Fair Value
					at Date of Grant
	Unvested balance at December 31, 2011	1,256,478			$	5.63
	Granted	341,541			$	5.79
	Vested	(734,380	)		$	4.18
	Forfeited	(53,648	)		$	6.52
	Unvested balance at December 31, 2012	809,991			$	6.96
	Granted	374,214			$	4.75
	Vested	(399,481	)		$	7.34
	Forfeited	(100,613	)		$	5.55
	Unvested balance at December 31, 2013	684,111			$	5.73
	Granted	—			$	—
	Vested	(381,787	)		$	6.28
Forfeited	—			$	—
Unvested balance at December 31, 2014	302,324			$	5.05
The following tables set forth the number of exercisable options as of December 31, 2014, 2013 and 2012 and the weighted average fair value and exercise price of these options at the grant date.
	Number of			Weighted Average
	Options			Fair Value
				at Date of Grant
Options Exercisable at December 31, 2011	646,365			$	2.61
Vested	734,380			$	4.18
Exercised	(113,955	)		$	2.56
Options Exercisable at December 31, 2012	1,266,790			$	3.52
Vested	399,481			$	7.34
Exercised	(250,472	)		$	2.35
Options Exercisable at December 31, 2013	1,415,799			$	4.81
Vested	381,787			$	6.28
Exercised	(507,056	)		$	3.54
Options Exercisable at December 31, 2014	1,290,530			$	5.74
	Exercisable			Intrinsic Value				Weighted Average				Weighted Average
	Options							Exercise Price				Remaining
												Contractual Term
As of December 31, 2012	1,266,790			$	17.6	million		$	10.24			6.6 years
As of December 31, 2013	1,415,799			$	14.7	million		$	14.33			6.1 years
As of December 31, 2014	1,290,530			$	19.3	million		$	18.27			5.8 years
The intrinsic value of stock options exercised during the years ended December 31, 2014, 2013 and 2012 was $7.7 million, $4.5 million and $1.9 million, respectively.
The fair value of each option award is estimated on the date of grant using a Black-Scholes option valuation model. Expected volatility used in the Black-Scholes model is based on DFT’s historical volatility. The risk-free rate for periods within the contractual life of the option is based on the U.S. Treasury yield curve in effect at the time of grant. The following table summarizes the assumptions used to value the stock options granted and the fair value of these options granted during the years ended December 31, 2013 and 2012.
	2013				2012
Number of options granted	374,214				341,541
Exercise price	$	22.62			$	22.57
Expected term (in years)	5				4
Expected volatility	34		%		39		%
Expected annual dividend	4		%		2		%
Risk-free rate	0.83		%		0.64		%
Fair value at date of grant	$1.8 million				$2.0 million
Performance Units
Performance unit awards are awarded to certain executive employees and have a three calendar-year performance period with no dividend rights. Performance units will be settled in common shares following the performance period as long as the employee remains employed with us on the vesting date, which is the March 1st date following the last day of the applicable performance period. Performance units are valued using a Monte Carlo simulation and are amortized over the three year vesting period from the grant date to the vesting date. The number of common shares settled could range from 0% to 300%. For performance unit award grants prior to 2014, the vesting amount is dependent on DFT’s total stockholder return compared to the MSCI US REIT index over the three calendar-year performance period.
For performance unit grants awarded in 2014, one-half of the recipient's performance unit award is dependent on DFT’s total stockholder return compared to the MSCI US REIT index over the three calendar-year performance period. The other half of the performance unit award is dependent on DFT’s total stockholder return compared to an index of five comparable publicly traded data center companies over the three calendar-year performance period. For performance unit grants awarded in 2013 and 2012, the entire award is dependent on DFT’s total stockholder return compared to the MSCI US REIT index over the three calendar-year performance period. The following table summarizes the assumptions used to value, and the resulting fair and maximum values of, the performance units granted during the years ended December 31, 2014, 2013 and 2012.
	2014				2013				2012
Number of performance units granted	110,441				60,468				61,033
Expected volatility	30		%		33		%		29		%
Expected annual dividend	5		%		4		%		2		%
Risk-free rate	0.74		%		0.4		%		0.43		%
Performance unit fair value at date of grant	$	33.5			$	25.59			$	28.26
Total grant fair value at date of grant	$3.7 million				$1.5 million				$1.7 million
Maximum value of grant on vesting date based on closing price of DFT's stock at the date of grant	$8.5 million				$4.1 million				$4.1 million
During the year ended December 31, 2014, no performance units were forfeited. During the year ended December 31, 2013, 22,091 performance units were forfeited with a weighted average fair value of $26.93 per unit. As of December 31, 2014, total unearned compensation on outstanding performance units was $3.2 million.
For the performance units granted in 2012, based on DFT’s total stockholder return compared to the MSCI US REIT index return for the period from January 1, 2012 to January 1, 2015, no common shares will be issued upon their vesting on March 1, 2015.

13_Earnings_Per_Share_of_the_R

13. Earnings Per Share of the REIT	12 Months Ended
	Dec. 31, 2014
Earnings Per Share [Abstract]
Earnings Per Share [Text Block]	Earnings Per Share of DFT
	The following table sets forth the reconciliation of basic and diluted average shares outstanding used in the computation of earnings per share of common stock (in thousands except for share and per share amounts):
		Twelve months ended December 31,
		2014				2013			2012
	Basic and Diluted Shares Outstanding
	Weighted average common shares – basic	65,486,108				64,645,316			62,866,189
	Effect of dilutive securities	600,271				828,723			887,817
	Weighted average common shares – diluted	66,086,379				65,474,039			63,754,006
	Calculation of Earnings per Share – Basic
	Net income attributable to common shares	$	78,662			$	21,146		$	25,977
	Net income allocated to unvested restricted shares	(484		)		(267		)	(188		)
	Net income attributable to common shares, adjusted	78,178				20,879			25,789
	Weighted average common shares – basic	65,486,108				64,645,316			62,866,189
	Earnings per common share – basic	$	1.19			$	0.32		$	0.41
	Calculation of Earnings per Share – Diluted
	Net income attributable to common shares	$	78,178			$	21,146		$	25,977
	Adjustments to redeemable noncontrolling interests	—				55			84
	Adjusted net income available to common shares	78,178				21,201			26,061
	Weighted average common shares – diluted	66,086,379				65,474,039			63,754,006
	Earnings per common share – diluted	$	1.18			$	0.32		$	0.41
	The following table sets forth the amount of restricted shares, stock options and performance units that have been excluded from the calculation of diluted earnings per share as their effect would have been antidilutive (in millions):
		Twelve months ended December 31,
		2014			2013			2012
	Restricted Shares	—			—			—
	Stock Options	—			0.6			0.9
	Performance Units	0.1			0.1			0.1

14_Earnings_Per_Unit_of_the_Op

14. Earnings Per Unit of the Operating Partnership	12 Months Ended
	Dec. 31, 2014
Earnings Per Unit [Abstract]
Earnings per unit of the Operating Partnership [Text Block]	Earnings Per Unit of the Operating Partnership
	The following table sets forth the reconciliation of basic and diluted average units outstanding used in the computation of earnings per unit:
		Twelve months ended December 31,
		2014	2013	2012
	Basic and Diluted Units Outstanding
	Weighted average common units – basic (includes redeemable partnership units and units of general and limited partners)	81,053,127	80,580,556	81,750,958
	Effect of dilutive securities	600,271	828,723	887,817
	Weighted average common units – diluted	81,653,398	81,409,279	82,638,775
	The following table sets forth the amount of restricted units, stock options and performance units that have been excluded from the calculation of diluted earnings per unit as their effect would have been antidilutive (in millions):
		Twelve months ended December 31,
		2014	2013	2012
	Restricted Units	—	—	—
	Stock Options	—	0.6	0.9
	Performance Units	0.1	0.1	0.1

15_Employee_Benefit_Plan_Notes

15. Employee Benefit Plan (Notes)	12 Months Ended
	Dec. 31, 2014
Compensation and Employee Benefit Plans [Text Block]	Employee Benefit Plan
	We have a tax qualified retirement plan (“401(k) Plan”) that provides employees with an opportunity to save for retirement on a tax advantaged basis. Employees participate in the 401(k) Plan on their first day of employment and are able to defer compensation up to the limits established by the Internal Revenue Service. We match 50% of the employees' contributions up to a maximum match contribution of 4% of the employee's eligible compensation. Our contributions vest immediately. During each of the years ended December 31, 2014, 2013 and 2012, we contributed $0.4 million to the 401(k) Plan.

16_Fair_Value

16. Fair Value	12 Months Ended
	Dec. 31, 2014
Fair Value Disclosures [Abstract]
Fair Value Disclosures [Text Block]	Fair Value
	Assets and Liabilities Measured at Fair Value
	We follow the authoritative guidance issued by the FASB relating to fair value measurements that defines fair value, establishes a framework for measuring fair value, and expands disclosures about fair value measurements. The guidance applies to reported balances that are required or permitted to be measured at fair value under existing accounting pronouncements; accordingly, the guidance does not require any new fair value measurements of reported balances. The guidance excludes the accounting for leases, as well as other authoritative guidance that address fair value measurements on lease classification and measurement. The authoritative guidance issued by the FASB 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.
	Level 1 inputs utilize quoted prices (unadjusted) in active markets for identical assets or liabilities that we have the ability to access. Level 2 inputs are inputs other than quoted prices included in Level 1 that are observable for the asset or liability, either directly or indirectly. Level 2 inputs may include quoted prices for similar assets and liabilities in active markets, as well as inputs that are observable for the asset or liability (other than quoted prices), such as interest rates, foreign exchange rates, and yield curves that are observable at commonly quoted intervals. Level 3 inputs are unobservable inputs for the asset or liability, which are typically based on an entity's own assumptions, as there is little, if any, related market activity. In instances where the determination of the fair value measurement is based on inputs from different levels of the fair value hierarchy, the level in the fair value hierarchy within which the entire fair value measurement falls is based on the lowest level input that is significant to the fair value measurement in its entirety. Our assessment of the significance of a particular input to the fair value measurement in its entirety requires judgment, and considers factors specific to the asset or liability. As of December 31, 2014 and 2013, we had no fair value measurements based on level 3 inputs.
	The authoritative guidance issued by the FASB requires disclosure of the fair value of financial instruments. Fair value estimates are subjective in nature and are dependent on a number of important assumptions, including estimates of future cash flows, risks, discount rates, and relevant comparable market information associated with each financial instrument. The use of different market assumptions and estimation methodologies may have a material effect on the reported estimated fair value amounts. Accordingly, the amounts are not necessarily indicative of the amounts we would realize in a current market exchange.
	The following methods and assumptions were used in estimating the fair value amounts and disclosures for financial instruments as of December 31, 2014 and 2013:
	•	Cash and cash equivalents: The carrying amount of cash and cash equivalents reported in the accompanying consolidated balance sheets approximates fair value because of the short maturity of these instruments (i.e., less than 90 days).
	•	Rents and other receivables, accounts payable and accrued liabilities, and prepaid rents: The carrying amount of these assets and liabilities reported in the accompanying consolidated balance sheets approximates fair value because of the short-term nature of these amounts.
	•	Debt: As of December 31, 2014, the combined balance of our Unsecured Notes due 2021, Unsecured Term Loan, Unsecured Credit Facility and ACC3 Term Loan was $1,025.0 million with a fair value of $1,037.8 million based on Level 2 data. The Unsecured Notes due 2021 were valued based on Level 2 data which consisted of a quoted price for the Unsecured Notes due 2021 from a third party financial market data provider. Because our ACC3 Term Loan, Unsecured Credit Facility and Unsecured Term Loan were refinanced in 2014, we believe that their carrying values approximate each of their fair values as of December 31, 2014. Each of these loans bear interest at LIBOR plus a spread that is consistent with current market conditions.
	As of December 31, 2013, the combined balance of our Unsecured Notes due 2021, Unsecured Term Loan and ACC3 Term Loan was $869.0 million with a fair value of $872.2 million based on Level 2 and Level 3 data. The Level 2 data was for the Unsecured Notes due 2021 and consisted of a quote from the market maker in the Unsecured Notes due 2021. The Level 3 data is for the ACC3 Loan and the Unsecured Term Loan and is based on discounted cash flows using the one-month LIBOR swap rate of 1.68% as of December 31, 2013 plus a spread that was consistent with current market conditions.

17_Quarterly_Financial_Informa

17. Quarterly Financial Information (Notes)	12 Months Ended
	Dec. 31, 2014
Quarterly Financial Information Disclosure [Abstract]
Quarterly Financial Information [Text Block]	Quarterly Financial Information (unaudited)
	The table below reflects the selected quarterly information for the years ended December 31, 2014 and 2013 (in thousands except share data):
		Three months ended
		December 31, 2014		September 30, 2014			June 30, 2014		March 31, 2014
	Total revenue	$	107,977	$	105,578		$	101,950	$	102,087
	Net income	29,737		30,272			32,958		31,644
	Net income attributable to common shares	18,536		18,960			21,121		20,045
	Net income attributable to common shares per common share-basic	0.28		0.29			0.32		0.3
	Net income attributable to common shares per common share-diluted (1)	0.28		0.29			0.32		0.3
		Three months ended
		December 31, 2013		September 30, 2013			June 30, 2013		March 31, 2013
	Total revenue	$	99,444	$	96,342		$	91,564	$	87,759
	Net income (loss)	21,089		(5,958		)	21,747		16,727
	Net income (loss) attributable to common shares	11,460		(10,228		)	11,971		7,943
	Net income (loss) attributable to common shares per common share-basic (2)	0.18		(0.16		)	0.19		0.12
	Net income (loss) attributable to common shares per common share-diluted	0.18		(0.16		)	0.18		0.12
	(1) Amounts do not equal full year results due to rounding in the second quarter of 2014.
	(2) Amounts do not equal full year results due to rounding and the impact of the loss in the third quarter of 2013.

18_Supplemental_Consolidating_

18. Supplemental Consolidating Financial Data for Subsidiary Guarantors of the Unsecured Notes	12 Months Ended
	Dec. 31, 2014
Supplemental Consolidating Financial Data for Subsidiary Guarantors of the Unsecured Notes [Abstract]
Additional Financial Information Disclosure [Text Block]	18. Supplemental Consolidating Financial Data for Subsidiary Guarantors of the Unsecured Notes
	On September 24, 2013, the Operating Partnership issued the Unsecured Notes due 2021 (See Note 6). The Unsecured Notes due 2021 are unconditionally guaranteed, jointly and severally on a senior unsecured basis by DFT and certain of our subsidiaries, including the subsidiaries that own the ACC2, ACC4, ACC5, ACC6, VA3, VA4, CH1, NJ1 and SC1 data centers and the SC2 land (collectively, the "Subsidiary Guarantors"), but excluding the subsidiaries that own the ACC3 and ACC7 data center facilities, the CH2 data center under development, the ACC8 land and the TRS collectively, the "Subsidiary Non-Guarantors"). The following consolidating financial information sets forth the financial position as of December 31, 2014 and December 31, 2013 and the results of operations and cash flows for the years ended December 31, 2014, 2013 and 2012 of the Operating Partnership, Subsidiary Guarantors and the Subsidiary Non-Guarantors.
	DUPONT FABROS TECHNOLOGY, L.P.
	SUPPLEMENTAL CONSOLIDATING BALANCE SHEETS
	(in thousands except share data)
		December 31, 2014
		Operating			Subsidiary			Subsidiary			Eliminations			Consolidated
		Partnership			Guarantors			Non-Guarantors						Total
	ASSETS
	Income producing property:
	Land	$	—		$	79,935		$	3,858		$	—		$	83,793
	Buildings and improvements	—			2,427,706			195,833			—			2,623,539
		—			2,507,641			199,691			—			2,707,332
	Less: accumulated depreciation	—			(473,203		)	(31,666		)	—			(504,869		)
	Net income producing property	—			2,034,438			168,025			—			2,202,463
	Construction in progress and land held for development	—			145,229			213,736			—			358,965
	Net real estate	—			2,179,667			381,761			—			2,561,428
	Cash and cash equivalents	21,806			—			3,574			—			25,380
	Rents and other receivables	1,775			5,513			825			—			8,113
	Deferred rent	—			139,542			2,823			—			142,365
	Lease contracts above market value, net	—			8,054			—			—			8,054
	Deferred costs, net	15,957			16,098			6,440			—			38,495
	Investment in affiliates	2,547,049			—			—			(2,547,049		)	—
	Prepaid expenses and other assets	2,865			43,866			1,564			—			48,295
	Total assets	$	2,589,452		$	2,392,740		$	396,987		$	(2,547,049	)	$	2,832,130
	LIABILITIES AND PARTNERS’ CAPITAL
	Liabilities:
	Line of credit	$	60,000		$	—		$	—		$	—		$	60,000
	Mortgage notes payable	—			—			115,000			—			115,000
	Unsecured term loan	250,000			—			—			—			250,000
	Unsecured notes payable	600,000			—			—			—			600,000
	Accounts payable and accrued liabilities	4,432			19,580			2,961			—			26,973
	Construction costs payable	—			4,312			28,637			—			32,949
	Accrued interest payable	10,754			—			5			—			10,759
	Distribution payable	39,981			—			—			—			39,981
	Lease contracts below market value, net	—			7,037			—			—			7,037
	Prepaid rents and other liabilities	28			61,728			3,418			—			65,174
	Total liabilities	965,195			92,657			150,021			—			1,207,873
	Redeemable partnership units	513,134			—			—			—			513,134
	Commitments and contingencies	—			—			—			—			—
	Limited Partners’ Capital:
	Series A cumulative redeemable perpetual preferred units, 7,400,000 issued and outstanding at December 31, 2014	185,000			—			—			—			185,000
	Series B cumulative redeemable perpetual preferred units, 6,650,000 issued and outstanding at December 31, 2014	166,250			—			—			—			166,250
	Common units, 65,189,792 issued and outstanding at December 31, 2014	752,254			2,300,083			246,966			(2,547,049		)	752,254
	General partner’s capital, 662,373 common units issued and outstanding at December 31, 2014	7,619			—			—			—			7,619
	Total partners’ capital	1,111,123			2,300,083			246,966			(2,547,049		)	1,111,123
	Total liabilities & partners’ capital	$	2,589,452		$	2,392,740		$	396,987		$	(2,547,049	)	$	2,832,130
	DUPONT FABROS TECHNOLOGY, L.P.
	SUPPLEMENTAL CONSOLIDATING BALANCE SHEETS
	(in thousands except share data)
		December 31, 2013
		Operating			Subsidiary			Subsidiary			Eliminations			Consolidated
		Partnership			Guarantors			Non-Guarantors						Total
	ASSETS
	Income producing property:
	Land	$	—		$	74,885		$	1,071		$	—		$	75,956
	Buildings and improvements	—			2,318,414			102,572			—			2,420,986
		—			2,393,299			103,643			—			2,496,942
	Less: accumulated depreciation	—			(386,796		)	(26,598		)	—			(413,394		)
	Net income producing property	—			2,006,503			77,045			—			2,083,548
	Construction in progress and land held for development	—			154,404			147,664			—			302,068
	Net real estate	—			2,160,907			224,709			—			2,385,616
	Cash and cash equivalents	32,903			—			1,611			—			34,514
	Rents and other receivables	4,226			3,981			4,467			—			12,674
Deferred rent	—			144,377			5,661			—			150,038
Lease contracts above market value, net	—			9,154			—			—			9,154
Deferred costs, net	17,318			16,971			5,577			—			39,866
Investment in affiliates	2,372,121			—			—			(2,372,121		)	—
Prepaid expenses and other assets	2,264			37,331			4,912			—			44,507
Total assets	$	2,428,832		$	2,372,721		$	246,937		$	(2,372,121	)	$	2,676,369
LIABILITIES AND PARTNERS’ CAPITAL
Liabilities:
Line of credit	$	—		$	—		$	—		$	—		$	—
Mortgage notes payable	—			—			115,000			—			115,000
Unsecured term loan	154,000			—			—			—			154,000
Unsecured notes payable	600,000			—			—			—			600,000
Accounts payable and accrued liabilities	3,547			14,582			5,437			—			23,566
Construction costs payable	—			22,670			22,774			—			45,444
Accrued interest payable	9,970			—			13			—			9,983
Distribution payable	25,971			—			—			—			25,971
Lease contracts below market value, net	—			10,530			—			—			10,530
Prepaid rents and other liabilities	45			49,915			6,616			—			56,576
Total liabilities	793,533			97,697			149,840			—			1,041,070
Redeemable partnership units	387,244			—			—			—			387,244
Commitments and contingencies	—			—			—			—			—
Limited Partners’ Capital:
Series A cumulative redeemable perpetual preferred units, 7,400,000 issued and outstanding at December 31, 2013	185,000			—			—			—			185,000
Series B cumulative redeemable perpetual preferred units, 6,650,000 issued and outstanding at December 31, 2013	166,250			—			—			—			166,250
Common units, 64,542,901 issued and outstanding at December 31, 2013	887,695			2,275,024			97,097			(2,372,121		)	887,695
General partner’s capital, 662,373 common units issued and outstanding at December 31, 2013	9,110			—			—			—			9,110
DUPONT FABROS TECHNOLOGY, L.P.
SUPPLEMENTAL CONSOLIDATING BALANCE SHEETS
(in thousands)
(Continued)
	December 31, 2013
	Operating			Subsidiary			Subsidiary			Eliminations			Consolidated
	Partnership			Guarantors			Non-Guarantors						Total
Total partners’ capital	1,248,055			2,275,024			97,097			(2,372,121		)	1,248,055
Total liabilities & partners’ capital	$	2,428,832		$	2,372,721		$	246,937		$	(2,372,121	)	$	2,676,369
	Year ended December 31, 2014
	Operating			Subsidiary			Subsidiary			Eliminations			Consolidated
	Partnership			Guarantors			Non-Guarantors						Total
Revenues:
Base rent	$	17,499		$	267,454		$	18,413		$	(17,650	)	$	285,716
Recoveries from tenants	—			115,185			9,668			—			124,853
Other revenues	—			1,657			5,489			(123		)	7,023
Total revenues	17,499			384,296			33,570			(17,773		)	417,592
Expenses:
Property operating costs	—			123,140			11,822			(17,623		)	117,339
Real estate taxes and insurance	—			13,323			872			—			14,195
Depreciation and amortization	63			90,770			5,947			—			96,780
General and administrative	16,159			82			940			—			17,181
Other expenses	3,508			1,526			4,338			(150		)	9,222
Total expenses	19,730			228,841			23,919			(17,773		)	254,717
Operating (loss) income	(2,231		)	155,455			9,651			—			162,875
Interest income	115			—			1			—			116
Interest:
Expense incurred	(41,222		)	4,323			3,200			—			(33,699		)
Amortization of deferred financing costs	(3,173		)	273			(80		)	—			(2,980		)
Loss on early extinguishment of debt	(1,701		)	—			—			—			(1,701		)
Equity in earnings	172,823			—			—			(172,823		)	—
Net income (loss)	124,611			160,051			12,772			(172,823		)	124,611
Preferred unit distributions	(27,245		)	—			—			—			(27,245		)
Net income (loss) attributable to common units	$	97,366		$	160,051		$	12,772		$	(172,823	)	$	97,366
	Year ended December 31, 2013
	Operating			Subsidiary			Subsidiary			Eliminations			Consolidated
	Partnership			Guarantors			Non-Guarantors						Total
Revenues:
Base rent	$	15,301		$	248,719		$	17,126		$	(15,451	)	$	265,695
Recoveries from tenants	—			94,794			9,477			—			104,271
Other revenues	—			1,668			3,613			(138		)	5,143
Total revenues	15,301			345,181			30,216			(15,589		)	375,109
Expenses:
Property operating costs	198			108,536			10,227			(15,439		)	103,522
Real estate taxes and insurance	—			13,931			449			—			14,380
Depreciation and amortization	81			88,556			4,421			—			93,058
General and administrative	15,605			97			559			—			16,261
Other expenses	778			304			2,718			(150		)	3,650
Total expenses	16,662			211,424			18,374			(15,589		)	230,871
Operating (loss) income	(1,361		)	133,757			11,842			—			144,238
Interest income	(148		)	20			—			265			137
Interest:
Expense incurred	(47,343		)	351			814			(265		)	(46,443		)
Amortization of deferred financing costs	(3,054		)	(167		)	(128		)	—			(3,349		)
Loss on early extinguishment of debt	(39,278		)	(1,700		)	—			—			(40,978		)
Equity in earnings	144,789			—			—			(144,789		)	—
Net income (loss)	53,605			132,261			12,528			(144,789		)	53,605
Preferred unit distributions	(27,245		)	—			—			—			(27,245		)
Net income (loss) attributable to common units	$	26,360		$	132,261		$	12,528		$	(144,789	)	$	26,360
	Year ended December 31, 2012
	Operating			Subsidiary			Subsidiary			Eliminations			Consolidated
	Partnership			Guarantors			Non-Guarantors						Total
Revenues:
Base rent	$	13,765		$	218,208		$	18,752		$	(13,915	)	$	236,810
Recoveries from tenants	—			80,387			10,662			—			91,049
Other revenues	—			1,378			3,335			(127		)	4,586
Total revenues	13,765			299,973			32,749			(14,042		)	332,445
Expenses:
Property operating costs	—			97,036			11,502			(13,892		)	94,646
Real estate taxes and insurance	—			12,167			522			—			12,689
Depreciation and amortization	117			83,902			5,222			—			89,241
General and administrative	14,531			128			2,365			—			17,024
Other expenses	1,437			3,031			2,601			(150		)	6,919
Total expenses	16,085			196,264			22,212			(14,042		)	220,519
Operating (loss) income	(2,320		)	103,709			10,537			—			111,926
Interest income	432			—			—			(264		)	168
Interest:
Expense incurred	(47,535		)	(420		)	(74		)	264			(47,765		)
Amortization of deferred financing costs	(2,748		)	(760		)	12			—			(3,496		)
Equity in earnings	113,004			—			—			(113,004		)	—
Net income (loss)	60,833			102,529			10,475			(113,004		)	60,833
Preferred unit distributions	(27,053		)	—			—			—			(27,053		)
Net income (loss) attributable to common units	$	33,780		$	102,529		$	10,475		$	(113,004	)	$	33,780
DUPONT FABROS TECHNOLOGY, L.P.
SUPPLEMENTAL CONSOLIDATING STATEMENTS OF CASH FLOWS
(in thousands)
	Year ended December 31, 2014
	Operating			Subsidiary			Subsidiary			Eliminations			Consolidated
	Partnership			Guarantors			Non-Guarantors						Total
Cash flow from operating activities
Net cash (used in) provided by operating activities	$	(40,234	)	$	264,409		$	20,339		$	—		$	244,514
Cash flow from investing activities
Investments in real estate – development	(404		)	(111,791		)	(153,179		)	—			(265,374		)
Land acquisition costs	—			—			—			—			—
Investments in affiliates	5,654			(146,188		)	140,534			—			—
Interest capitalized for real estate under development	(10		)	(4,323		)	(5,311		)	—			(9,644		)
Improvements to real estate	—			(1,850		)	(66		)	—			(1,916		)
Additions to non-real estate property	(20		)	(257		)	(39		)	—			(316		)
Net cash provided by (used in) investing activities	5,220			(264,409		)	(18,061		)	—			(277,250		)
Cash flow from financing activities
Line of credit:
Proceeds	60,000			—			—			—			60,000
Unsecured term loan:
Proceeds	96,000			—			—			—			96,000
Payments of financing costs	(3,514		)	—			(315		)	—			(3,829		)
Issuance of OP units for stock option exercises, net	4,363			—			—			—			4,363
Distributions	(132,932		)	—			—			—			(132,932		)
Net cash used in financing activities	23,917			—			(315		)	—			23,602
Net (decrease) increase in cash and cash equivalents	(11,097		)	—			1,963			—			(9,134		)
Cash and cash equivalents, beginning	32,903			—			1,611			—			34,514
Cash and cash equivalents, ending	$	21,806		$	—		$	3,574		$	—		$	25,380
DUPONT FABROS TECHNOLOGY, L.P.
SUPPLEMENTAL CONSOLIDATING STATEMENTS OF CASH FLOWS
(in thousands)
	Year ended December 31, 2013
	Operating			Subsidiary			Subsidiary			Eliminations			Consolidated
	Partnership			Guarantors			Non-Guarantors						Total
Cash flow from operating activities
Net cash (used in) provided by operating activities	$	(48,725	)	$	225,903		$	16,583		$	—		$	193,761
Cash flow from investing activities
Investments in real estate – development	(9		)	(50,827		)	(78,496		)	—			(129,332		)
Land acquisition costs	—			—			(14,186		)	—			(14,186		)
Investments in affiliates	62,508			(28,856		)	(33,652		)	—			—
Interest capitalized for real estate under development	—			(1,399		)	(2,375		)	—			(3,774		)
Improvements to real estate	—			(5,513		)	(244		)	—			(5,757		)
Additions to non-real estate property	(6		)	(65		)	—			—			(71		)
Net cash provided by (used in) investing activities	62,493			(86,660		)	(128,953		)	—			(153,120		)
Cash flow from financing activities
Line of credit:
Proceeds	102,000			—			—			—			102,000
Repayments	(120,000		)	—			—			—			(120,000		)
Mortgage notes payable:
Proceeds	—			—			115,000			—			115,000
Lump sum payoffs	—			(138,300		)	—			—			(138,300		)
Repayments	—			(1,300		)	—			—			(1,300		)
Unsecured term loan:
Proceeds	154,000			—			—			—			154,000
Unsecured notes payable:
Proceeds	600,000			—			—			—			600,000
Repayments	(550,000		)	—			—			—			(550,000		)
Payments of financing costs	(16,419		)	(4		)	(1,700		)	—			(18,123		)
Payments for early extinguishment of debt	(32,544		)	—			—			—			(32,544		)
Issuance of OP units for stock option exercises, net	1,711			—			—			—			1,711
Stock repurchases	(37,792		)	—			—			—			(37,792		)
Distributions	(100,061		)	—			—			—			(100,061		)
Net cash provided by (used in) financing activities	895			(139,604		)	113,300			—			(25,409		)
Net increase (decrease) in cash and cash equivalents	14,663			(361		)	930			—			15,232
Cash and cash equivalents, beginning	18,240			361			681			—			19,282
Cash and cash equivalents, ending	$	32,903		$	—		$	1,611		$	—		$	34,514
	Year ended December 31, 2012
	Operating			Subsidiary			Subsidiary			Eliminations			Consolidated
	Partnership			Guarantors			Non-Guarantors						Total
Cash flow from operating activities
Net cash (used in) provided by operating activities	$	(49,869	)	$	168,236		$	14,396		$	—		$	132,763
Cash flow from investing activities
Investments in real estate – development	(26		)	(84,877		)	(9,850		)	—			(94,753		)
Land Acquisition Costs	—			(3,830		)	—			—			(3,830		)
Investments in affiliates	69,833			(65,480		)	(4,353		)	—			—
Interest capitalized for real estate under development	—			(4,244		)	(190		)	—			(4,434		)
Improvements to real estate	—			(4,395		)	(31		)	—			(4,426		)
Additions to non-real estate property	(19		)	(20		)	(18		)	—			(57		)
Net cash used in investing activities	69,788			(162,846		)	(14,442		)	—			(107,500		)
Cash flow from financing activities
Line of credit:
Proceeds	48,000			—			—			—			48,000
Repayments	(50,000		)	—			—			—			(50,000		)
Mortgage notes payable:
Repayments	—			(5,200		)	—			—			(5,200		)
Payments of financing costs	(2,084		)	(25		)	—			—			(2,109		)
Issuance of preferred units, net of offering costs	62,694			—			—			—			62,694
Issuance of OP units for stock option exercises, net	868			—			—			—			868
Distributions	(70,331		)	—			—			—			(70,331		)
Net cash provided by (used in) financing activities	(10,853		)	(5,225		)	—			—			(16,078		)
Net (decrease) increase in cash and cash equivalents	9,066			165			(46		)	—			9,185
Cash and cash equivalents, beginning	9,174			196			727			—			10,097
Cash and cash equivalents, ending	$	18,240		$	361		$	681		$	—		$	19,282

Schedule_II_Consolidated_Allow

Schedule II - Consolidated Allowance for Doubtful Accounts (Notes)	12 Months Ended
	Dec. 31, 2014
Valuation and Qualifying Accounts Disclosure [Line Items]
Schedule of Valuation and Qualifying Accounts Disclosure [Text Block]
		Balance at Beginning of Period		Charges to Operations		Net Recovery (Deductions)			Balance at End of Period
	Allowance for doubtful accounts:
	Twelve months ended December 31, 2014	$	3,700	$	4,829	$	(9	)	$	8,520
	Twelve months ended December 31, 2013	2,961		739		—			3,700
	Twelve months ended December 31, 2012	—		2,961		—			2,961

Schedule_III_Consolidated_Real

Schedule III - Consolidated Real Estate and Accumulated Depreciation (Notes)	12 Months Ended
	Dec. 31, 2014
Real Estate and Accumulated Depreciation [Line Items]
SEC Schedule III, Real Estate and Accumulated Depreciation Disclosure [Text Block]
			Encum-brances			Initial Cost					Cost Capitalized				Gross Carry Amount at								Accumulated			Year	Year
											Subsequent to Acquisition				December 31, 2014								Depreciation at			Built/	Acquired
																							December 31,			Renovated
						Land			Buildings &		Land		Buildings &		Land			Buildings &			Total		2014
									Improvements				Improvements					Improvements
	Operating Properties
	ACC2 (1)		$	—		$	2,500		$	157,100	$	—	$	2,058	$	2,500		$	159,158		$	161,658	$	(50,035	)	2005	2001
	ACC3 (2)		115,000			1,071			—		—		95,926		1,071		1	95,926		1	96,997		(29,313		)	2006	2001
	ACC4 (1)		—			6,600			506,081		—		32,470		6,600		2	538,551		2	545,151		(137,876		)	2007	2006
	ACC5 (1)		—			6,443			43		—		298,478		6,443		3	298,521		3	304,964		(50,191		)	2009-2010	2007
	ACC6 (1)		—			5,518			214,294		—		2,403		5,518		4	216,697		4	222,215		(20,207		)	2009-2011	2007
	ACC7 Phase I		—			2,787					—		92,989		2,787		4	92,989		4	95,776		(1,315		)	2014	2011
	CH1 (1)		—			22,450			238,746		1,161		119,666		23,611		5	358,412		5	382,023		(57,891		)	2007-2008	2007
	NJ1 Phase I (1)		—			4,311			191,649		—		18,487		4,311		6	210,136		6	214,447		(29,064		)	2008-2010	2007
	SC1 Phase I and IIA (1)		—			15,152			—		—		325,537		15,152		7	325,537		7	340,689		(25,581		)	2008-2014	2007
	VA3 (1)		—			9,000			172,881		—		5,481		9,000		8	178,362		8	187,362		(58,261		)	2003-2004	2003
	VA4 (1)		—			6,800			140,575		—		8,675		6,800		9	149,250		9	156,050		(45,135		)	2005	2005
	Subtotal		115,000			82,632			1,621,369		1,161		1,002,170		83,793			2,623,539			2,707,332		(504,869		)
	Development Properties
	SC1 Phase IIB (1)		—			5,049			95,591		—		—		5,049		8	95,591		8	100,640		—				2007
	ACC7 Phase II to IV		—			6,966			85,384		—		—		6,966		9	85,384		9	92,350		—				2011
	CH2		—			14,393			102,703		—		—		14,393		10	102,703		10	117,096		—				2013
	NJ1 Phase II (1)		—			4,318			34,894		—		—		4,318		11	34,894		11	39,212		—				2007
	ACC8		—			3,785			505		—		—		3,785		12	505		12	4,290		—				2007
	SC2 (1)		—			5,377			—		—		—		5,377		13	—		13	5,377		—				2007
	Subtotal		—			39,888			319,077		—		—		39,888			319,077			358,965		—
	Grand Total (3)		$	115,000		$	122,520		$	1,940,446	$	1,161	$	1,002,170	$	123,681		$	2,942,616		$	3,066,297	$	(504,869	)
	(1) The subsidiaries that own these data centers and development properties are guarantors of the Company's Unsecured Notes and Unsecured Credit Facility.
	(2) The subsidiary that owns this data center is encumbered by the Company's ACC3 Term Loan.
	(3) The aggregate gross cost of the Company's properties for federal income tax purposes was $2,360 million (unaudited) as of December 31, 2014.
		2014			2013			2012
	Real estate assets
	Balance, beginning of period	$	2,799,010		$	2,607,630		$	2,507,381
	Additions - property acquisitions	—			14,186			3,830
	Additions - improvements	267,357			177,194			96,419
	Deductions - write offs	(70		)	—			—
	Balance, end of period	$	3,066,297		$	2,799,010		$	2,607,630
	Accumulated depreciation
	Balance, beginning of period	$	413,394		$	325,740		$	242,245
	Additions - depreciation	91,545			87,654			83,495
	Deductions - write offs	(70		)	—			—
	Balance, end of period	$	504,869		$	413,394		$	325,740

2_Significant_Accounting_Polic1

2. Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
Basis of Presentation [Text Block]	Basis of Presentation
	This report combines the annual reports on Form 10-K for the year ended December 31, 2014 of DuPont Fabros Technology, Inc. and DuPont Fabros Technology, L.P. References to “DFT” mean DuPont Fabros Technology, Inc. and its controlled subsidiaries; and references to the “Operating Partnership” or “OP” mean DuPont Fabros Technology, L.P. and its controlled subsidiaries.
	We believe combining the annual reports on Form 10-K of DFT and the Operating Partnership into this single report provides the following benefits:
	•	enhances investors’ understanding of DFT 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 in this report applies to both DFT and the Operating Partnership; and
	•	creates time and cost efficiencies through the preparation of one combined report instead of two separate reports.
	We operate DFT and the Operating Partnership as one business. The management of DFT consists of the same employees as the management of the Operating Partnership.
	We believe it is important for investors to understand the few differences between DFT and the Operating Partnership in the context of how DFT and the Operating Partnership operate as a consolidated company. DFT is a REIT, whose only material asset is its ownership of OP units of the Operating Partnership. As a result, DFT does not conduct business itself, other than acting as the sole general partner of the Operating Partnership, issuing public equity from time to time and guaranteeing unsecured debt of the Operating Partnership. DFT has not issued any indebtedness, but has guaranteed all of the unsecured debt of the Operating Partnership. The Operating Partnership holds all the real estate assets of the Company. Except for net proceeds from public equity issuances by DFT, which are contributed to the Operating Partnership in exchange for OP units or preferred units, the Operating Partnership generates all remaining capital required by our business. These sources include the Operating Partnership’s operations, its direct or indirect incurrence of indebtedness, and the issuance of partnership units.
	As general partner with control of the Operating Partnership, DFT consolidates the Operating Partnership for financial reporting purposes. The presentation of stockholders’ equity and partners’ capital are the main areas of difference between the consolidated financial statements of DFT and those of the Operating Partnership. The Operating Partnership’s capital includes preferred units and general and limited common units that are owned by DFT and the other partners. DFT’s stockholders’ equity includes preferred stock, common stock, additional paid in capital and retained earnings. The common limited partnership interests held by the limited partners (other than DFT) in the Operating Partnership are presented as “redeemable partnership units” in the Operating Partnership’s consolidated financial statements and as “redeemable noncontrolling interests-operating partnership” in DFT’s consolidated financial statements. The only difference between the assets and liabilities of DFT and the Operating Partnership as of December 31, 2014 is a $4.2 million bank account held by DFT that is not part of the Operating Partnership. Net income is the same for DFT and the Operating Partnership.
	The accompanying consolidated financial statements have been prepared in accordance with U.S. generally accepted accounting principles, or GAAP. All significant intercompany accounts and transactions have been eliminated in the consolidated financial statements.
	We have one reportable segment consisting of investments in data centers located in the United States. All of our properties generate similar types of revenues and expenses related to customer rent and reimbursements and operating expenses. The delivery of our products is consistent across all properties and although services are provided to a range of customers, the types of services provided to them are limited to a few core principles. As such, the properties in our portfolio have similar economic characteristics and the nature of the products and services provided to our customers and the method to distribute such services are consistent throughout the portfolio.
Use of Estimates [Policy Text Block]	Use of Estimates
	The preparation of financial statements in conformity with GAAP requires us to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosures of contingent assets and liabilities at the date of the financial statements, and the reported amounts of revenue and expenses during the reporting period. Actual results could differ from those estimates.
Property [Policy Text Block]	Property
	All capital improvements for the income-producing properties that extend their useful life are capitalized to individual building components, including interest and real estate taxes incurred during the period of development, and depreciated over their estimated useful lives. Interest is capitalized during the period of development based upon applying the property’s specific borrowing rate to the actual development costs expended up to specific borrowings and then applying our weighted-average borrowing rate to any residual development costs expended during the construction period. Interest is capitalized until the property has reached substantial completion and is ready for its intended use. Interest costs capitalized totaled $10.2 million, $4.0 million and $4.7 million for the years ended December 31, 2014, 2013 and 2012, respectively. We cease interest capitalization when a development is temporarily suspended or placed in service.
	We capitalize pre-development costs, including internal costs, incurred in pursuit of new development opportunities for which we currently believe future development is probable. Future development is dependent upon various factors, including zoning and regulatory approval, rental market conditions, construction costs and availability of capital. Pre-development costs incurred for which future development is not yet considered probable are expensed as incurred. In addition, if the status of such a pre-development opportunity changes, making future development no longer probable, any capitalized pre-development costs are written-off with a charge to expense. Furthermore, the revenue from incidental operations received from the current improvements in excess of any incremental costs are being recorded as a reduction of total capitalized costs of the development project and not as a part of net income. The capitalization of costs during the development of assets (including interest and related loan fees, property taxes and other direct and indirect costs) begins when development efforts commence and ends when the asset, or a portion of the asset, is substantially complete and ready for its intended use. For the years ended December 31, 2014, 2013 and 2012, we capitalized $4.5 million, $3.3 million and $3.1 million, respectively, of internal development and leasing costs on all of our data centers.
	The fair value of in-place leases consists of the following components, as applicable: (1) the estimated cost to replace the leases, including foregone rents during the period of finding a new customer, foregone recovery of customer pass-through, customer improvements, and other direct costs associated with obtaining a new customer (referred to as Tenant Origination Costs); (2) the estimated leasing commissions associated with obtaining a new customer (referred to as Leasing Commissions); and (3) the above/below market cash flow of the leases, determined by comparing the projected cash flows of the leases in place to projected cash flows of comparable market-rate leases (referred to as Lease Intangibles). Tenant Origination Costs are included in buildings and improvements in our accompanying consolidated balance sheets and are amortized as depreciation expense on a straight-line basis over the average remaining life of the underlying leases. Leasing Commissions are classified as deferred costs and are amortized as amortization expense on a straight-line basis over the remaining life of the underlying leases. Lease Intangible assets and liabilities are classified as lease contracts above and below market value, respectively, and amortized on a straight-line basis as decreases and increases, respectively, to rental revenue over the remaining life of the underlying leases. Should a customer terminate its lease, the unamortized portions of Leasing Commissions and Lease Intangibles associated with that lease are written off to amortization expense, or rental revenue, respectively.
	Depreciation on buildings is generally provided on a straight-line basis over 40 years from the date the buildings were placed in service. Building components are depreciated over the life of the respective improvement ranging from 10 to 40 years from the date the components were placed in service. Personal property is depreciated over three years to seven years. Depreciation expense was $92.3 million, $88.6 million and $84.6 million for the years ended December 31, 2014, 2013 and 2012, respectively. Included in these amounts is amortization expense related to tenant origination costs, which was $3.1 million for each of the years ended December 31, 2014, 2013 and 2012. Repairs and maintenance costs are expensed as incurred.
	We record impairment losses on long-lived assets used in operations or in development when events or changes in circumstances indicate that the assets might be impaired, and the estimated undiscounted cash flows to be generated by those assets are less than the carrying amounts. If circumstances indicating impairment of a long-lived asset are present, we would determine the fair value of that asset, and an impairment loss would be recognized in an amount equal to the excess of the carrying amount of the impaired asset over its fair value. We assess the recoverability of the carrying value of our assets on a property-by-property basis. No impairment losses were recorded during the three years ended December 31, 2014.
	We classify a data center property as held-for-sale when it meets the necessary criteria, which include when we commit to and actively embark on a plan to sell the asset, the sale is expected to be completed within one year under terms usual and customary for such sales, and actions required to complete the plan indicate that it is unlikely that significant changes to the plan will be made or that the plan will be withdrawn. Data center properties held-for-sale are carried at the lower of cost or fair value less costs to sell. As of December 31, 2014, there were no data center properties classified as held-for-sale.
Cash and Cash Equivalents, Policy [Policy Text Block]	Cash and Cash Equivalents
	We consider all demand deposits and money market accounts purchased with a maturity date of three months or less, at the date of purchase, to be cash equivalents. Our account balances at one or more institutions exceed the Federal Deposit Insurance Corporation (“FDIC”) insurance coverage and, as a result, there is a concentration of credit risk related to amounts on deposit in excess of FDIC insurance coverage. We have not experienced any losses and believe that the risk is not significant.
Deferred Costs [Policy Text Block]	Deferred Costs
	Deferred costs, net in our accompanying consolidated balance sheets include both financing and leasing costs.
	Financing costs, which represent fees and other costs incurred in obtaining debt, are amortized using the effective-interest rate method or a method that approximates the effective-interest method, over the term of the loan and are included in amortization of deferred financing costs. In May 2014, we amended our unsecured revolving credit facility ("Unsecured Credit
	Facility"), which, due to the change in composition of lenders comprising the Unsecured Credit Facility's bank group, resulted in the partial write-off of unamortized deferred financing costs totaling $0.3 million. In July 2014, we amended our unsecured term loan agreement ("Unsecured Term Loan"), which, due to the change in composition of lenders comprising the Unsecured Term Loan's bank group, resulted in a loss on early extinguishment of debt of $1.4 million, which included a partial write-off of unamortized deferred financing costs of $0.7 million. In March 2013, we paid off the $138.3 million balance of the ACC5 Term Loan which resulted in a write-off of $1.7 million of unamortized deferred financing costs. In September and October 2013, we paid off the Unsecured Notes due 2017, which resulted in a write off of $6.7 million of unamortized deferred financing costs. Balances, net of accumulated amortization, at December 31, 2014 and 2013 are as follows (in thousands):
		December 31,
		2014				2013
	Financing costs	$	24,110			$	22,756
	Accumulated amortization	(6,820		)		(4,013		)
	Financing costs, net	$	17,290			$	18,743
	Leasing costs, which are either external fees and costs incurred in the successful negotiations of leases, internal costs expended in the successful negotiations of leases or the estimated leasing commissions resulting from the allocation of the purchase price of ACC2, VA3, VA4 and ACC4, are deferred and amortized over the terms of the related leases on a straight-line basis. If an applicable lease terminates prior to the expiration of its initial term, the carrying amount of the costs are written off to amortization expense. Leasing costs incurred for the years ended December 31, 2014, 2013 and 2012 are as follows:
		Year ended December 31,
		2014				2013			2012
	Costs incurred for new leases	$	2			$	0.9		$	1.3
	Costs incurred for renewals	0.2				1.2			—
	Costs incurred for re-leases	2				—			—
	Total leasing costs incurred	$	4.2			$	2.1		$	1.3
	Amortization of deferred leasing costs totaled $4.1 million, $4.1 million and $4.3 million for the years ended December 31, 2014, 2013 and 2012, respectively. Balances, net of accumulated amortization, at December 31, 2014 and 2013 are as follows (in thousands):
		December 31,
		2014				2013
	Leasing costs	$	52,358			$	48,312
	Accumulated amortization	(31,153		)		(27,189		)
	Leasing costs, net	$	21,205			$	21,123
Inventory [Policy Text Block]	Inventory
	We maintain fuel inventory for our generators, which is recorded at the lower of cost (on a first-in, first-out basis) or market. As of December 31, 2014 and 2013, the fuel inventory was $4.3 million and $4.0 million, respectively, and is included in prepaid expenses and other assets in the accompanying consolidated balance sheets.
Prepaid Rents [Policy Text Block]	Prepaid Rents
	Prepaid rents, typically prepayment of the following month’s rent, consist of payments received from customers prior to the time the payments are earned and are recognized as revenue in subsequent periods when earned.
Rental Income [Policy Text Block]	Rental Income
	We, as a lessor, have retained substantially all the risks and benefits of ownership and account for our leases as operating leases. For lease agreements that provide for scheduled fixed and determinable 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 and critical power have been provided to the customer. If the lease contains an early termination clause with a penalty payment, we determine the lease termination date by evaluating whether the penalty reasonably assures that the lease will not be terminated early. Lease inducements, which include free rent or cash payments to customers, are amortized as a reduction of rental income over the non-cancellable lease term. Straight-line rents receivable are included in deferred rent, net in the accompanying consolidated balance sheets. Lease intangible assets and liabilities that have resulted from above-market and below-market leases that were acquired are amortized on a straight-line basis as decreases and increases, respectively, to rental revenue over the remaining non-cancellable term of the underlying leases. If a lease terminates prior to the expiration of its initial term, the unamortized portion of lease intangibles associated with that lease will be written off to rental revenue. Balances, net of accumulated amortization, at December 31, 2014 and 2013 are as follows (in thousands):
		December 31,
		2014				2013
	Lease contracts above market value	$	23,100			$	23,100
	Accumulated amortization	(15,046		)		(13,946		)
	Lease contracts above market value, net	$	8,054			$	9,154
	Lease contracts below market value	$	39,375			$	39,375
	Accumulated amortization	(32,338		)		(28,845		)
	Lease contracts below market value, net	$	7,037			$	10,530
	Our policy is to record a reserve for losses on accounts receivable equal to the estimated uncollectible accounts. The estimate is based on our historical experience and a review of the current status of our receivables. As of December 31, 2014 and 2013, we had reserves against rents and other receivables of $4.9 million and $1.6 million, respectively. We also establish an appropriate allowance for doubtful accounts for receivables arising from the straight-lining of rents. These receivables arise from revenue recognized in excess of amounts currently due under the lease and are recorded as deferred rent in the accompanying consolidated balance sheets. As of December 31, 2014 and 2013, we had reserves against deferred rent of $3.7 million and $2.1 million, respectively.
	The reserves described above were set up for one customer that restructured its lease obligations with us during 2013. Under this restructuring, this customer's outstanding accounts receivable and deferred rent receivable related to the space that was returned to us were converted into a note receivable, the terms of which require the payment of principal and interest through December 31, 2016. Principal payments on the note are calculated on a ten-year amortization schedule with a final principal payment of the remaining note balance due on December 31, 2016. Additionally, under this restructuring, this customer deferred two-thirds of its base rent payments due for its lease at our NJ1 facility through July 2014, which were added to the note. Since that restructuring, we received all rent obligations and note payments due from this customer through the end of 2014. In January 2015, this customer informed us that they would be halting base rent payments and would pay only its monthly operating expenses, direct electric charges and management fees and its quarterly note payments until its company is sold or new funding sources are obtained. In February 2015, this customer filed a voluntary petition for relief under chapter 11 of the United States Bankruptcy Code.
	Due to the uncertainty surrounding this customer's ability to repay its note on its December 31, 2016 maturity, we increased the provision for bad debts related to this note by $2.4 million. Furthermore, to date, we have applied the interest portion of all note payments received, totaling $1.0 million, to the note principal balance on our consolidated balance sheet. The note balance as of December 31, 2014 and 2013 was $6.6 million and $5.7 million, respectively, which is recorded within rents and other receivables, net in our accompanying consolidated balance sheets. The note receivable balance, net of reserves and interest applied to the principal, as of December 31, 2014 and 2013 was $1.7 million and $4.1 million, respectively.
	Due to the uncertainty surrounding this customer's ability to pay its contractual rent obligations, we also reserved an additional $1.5 million of this customer's deferred rent receivable balance, resulting in a total reserve of $3.7 million on its deferred rent receivable balance of $9.5 million as of December 31, 2014.
	Customer leases generally contain provisions under which the customers reimburse us for a portion of operating expenses and real estate taxes incurred by the property. Recoveries from tenants are included in revenue in the consolidated statements of operations in the period the applicable expenditures are incurred. Most of our leases also provide us with a property management fee based on a percentage of base rent collected and property-level operating expenses, other than charges for power used by customers to run their servers and cool their space. Property management fees are included in base rent in the accompanying consolidated statements of operations in the applicable period in which they are earned.
Other Revenue [Policy Text Block]	Other Revenue
	Other revenue primarily consists of services provided to customers on a non-recurring basis. This includes projects such as the purchase and installation of circuits, racks, breakers and other customer requested items. Revenue is recognized on a completed contract basis when the project is finished and ready for the customer's use. This method is consistently applied for all periods presented. Costs of providing these services are included in other expenses in the accompanying consolidated statements of operations.
Income Tax, Policy [Policy Text Block]	Income Taxes
	DFT elected to be taxed as a REIT under the Internal Revenue Code of 1986, as amended (the “Code”), commencing with the taxable year ended December 31, 2007. In general, a REIT that meets certain organizational and operational requirements and distributes at least 90 percent of its REIT taxable income to its shareholders in a year will not be subject to income tax to the extent of the income it distributes. We currently qualify and intend to continue to qualify as a REIT under the Code. As a result, no provision for federal income taxes on income from continuing operations is required, except for taxes on certain property sales and on income, if any, of DF Technical Services, LLC, our taxable REIT subsidiary (“TRS”). If we fail to qualify as a REIT in any taxable year, we will be subject to federal income tax (including any applicable alternative minimum tax) on our income at regular corporate tax rates for the year in which we do not qualify and the succeeding four years. Although we expect to qualify for taxation as a REIT, we may be subject to state and local income and franchise taxes and to federal income and excise taxes on any undistributed income.
	As of December 31, 2014 and 2013, we did not have any unrecognized tax benefits. We do not believe that there will be any material changes in our unrecognized tax positions over the next 12 months. We are subject to examination by the respective taxing authorities for the tax years 2011 through 2014.
	We account for income taxes using the asset and liability method under which 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. Valuation allowances are provided if based upon the weight of the available evidence, it is more likely than not that some or all of the deferred tax assets will not be realized.
	In general, a TRS may perform non-customary services for customers, hold assets that DFT cannot hold directly and generally may engage in any real estate or non-real estate related business. A TRS is subject to corporate federal and state income taxes on its taxable income at regular statutory tax rates. For the year ended December 31, 2014, we incurred $0.1 million of income taxes. For the years ended December 31, 2013 and 2012, we incurred no income taxes.
	As of December 31, 2014, the TRS had a deferred tax asset of $5.5 million, comprised entirely of its net operating loss carryforward, and a deferred tax liability of $6.1 million, primarily comprised of a temporary depreciation difference, resulting in a net deferred tax liability of $0.6 million. As of December 31, 2014, we recorded deferred income tax expense of $0.2 million related to this deferred tax liability. As of December 31, 2013, the TRS had a deferred tax asset of $2.5 million, comprised entirely of its net operating loss carryforward, and a deferred tax liability of $2.5 million, primarily comprised of a temporary depreciation difference, resulting in a net deferred tax liability of $0. As of December 31, 2014, the net operating loss carryforwards of the TRS totaled approximately $5.5 million, which will begin to expire in 2031 if not utilized by then.
Redeemable Noncontrolling Interests—Operating Partnership / Redeemable Partnership Units [Policy Text Block]	Redeemable Noncontrolling Interests – Operating Partnership / Redeemable Partnership Units
	Redeemable noncontrolling interests – operating partnership, as presented on DFT’s consolidated balance sheets, represent the limited partnership interests in the Operating Partnership (“OP units”) held by individuals and entities other than DFT. These interests are also presented on the Operating Partnership’s consolidated balance sheets, referred to as “redeemable partnership units.” Accordingly, the following discussion related to redeemable noncontrolling interests – operating partnership of DFT refers equally to redeemable partnership units of the Operating Partnership.
	Redeemable noncontrolling interests – operating partnership, which require cash payment, or allow settlement in shares, but with the ability to deliver the shares outside of the control of DFT, are reported outside of the permanent equity section of the consolidated balance sheets of DFT and the Operating Partnership. Redeemable noncontrolling interests – operating partnership are adjusted for income, losses and distributions allocated to OP units not held by DFT (normal noncontrolling interest accounting amount). Adjustments to redeemable noncontrolling interests – operating partnership are recorded to reflect increases or decreases in the ownership of the Operating Partnership by holders of OP units, including the redemptions of OP units for cash or in exchange for shares of DFT’s common stock. If such adjustments result in redeemable noncontrolling interests – operating partnership being recorded at less than the redemption value of the OP units, redeemable noncontrolling interests – operating partnership are further adjusted to their redemption value (see Note 9). Redeemable noncontrolling interests – operating partnership are recorded at the greater of the normal noncontrolling interest accounting amount or redemption value. The following is a summary of activity for redeemable noncontrolling interests – operating partnership for the years ended December 31, 2014, 2013 and 2012 (dollars in thousands):
		OP Units
		Number			Amount
	Balance at December 31, 2011	19,064,381			$	461,739
	Net income attributable to redeemable noncontrolling interests – operating partnership	—			7,803
	Distributions declared	—			(11,683		)
	Redemption of operating partnership units	(277,575	)		(6,800		)
	Adjustments to redeemable noncontrolling interests – operating partnership	—			2,830
	Balance at December 31, 2012	18,786,806			$	453,889
	Net income attributable to redeemable noncontrolling interests – operating partnership	—			5,214
	Distributions declared	—			(15,050		)
	Redemption of operating partnership units	(3,115,269	)		(75,600		)
	Adjustments to redeemable noncontrolling interests – operating partnership	—			18,791
	Balance at December 31, 2013	15,671,537			$	387,244
	Net income attributable to redeemable noncontrolling interests – operating partnership	—			18,704
	Distributions declared	—			(22,831		)
	Redemption of operating partnership units	(234,300	)		(6,100		)
	Adjustments to redeemable noncontrolling interests – operating partnership	—			136,117
	Balance at December 31, 2014	15,437,237			$	513,134
	The following is a summary of activity for redeemable partnership units for the years ended December 31, 2014, 2013 and 2012 (dollars in thousands):
		OP Units
		Number			Amount
	Balance at December 31, 2011	19,064,381			$	461,739
	Redemption of operating partnership units	(277,575	)		(6,800		)
	Adjustments to redeemable partnership units	—			(1,050		)
	Balance at December 31, 2012	18,786,806			$	453,889
	Redemption of operating partnership units	(3,115,269	)		(75,600		)
	Adjustments to redeemable partnership units	—			8,955
	Balance at December 31, 2013	15,671,537			$	387,244
	Redemption of operating partnership units	(234,300	)		(6,100		)
	Adjustments to redeemable partnership units	—			131,990
	Balance at December 31, 2014	15,437,237			$	513,134
	Net income is allocated to controlling interests and redeemable noncontrolling interests – operating partnership in accordance with the limited partnership agreement of the Operating Partnership. The following is a summary of net income attributable to controlling interests and transfers to redeemable noncontrolling interests – operating partnership for the years ended December 31, 2014, 2013 and 2012 (dollars in thousands):
		Year ended December 31,
		2014				2013			2012
	Net income attributable to controlling interests	$	105,907			$	48,391		$	53,030
	Transfers from noncontrolling interests:
	Net change in the Company’s common stock and additional paid in capital due to the redemption of OP units and other adjustments to redeemable noncontrolling interests – operating partnership	(130,017		)		56,809			3,970
		$	(24,110	)		$	105,200		$	57,000
Earnings Per Share of the REIT [Policy Text Block]	Earnings Per Share of DFT
	Basic earnings per share is calculated by dividing the net income attributable to common shares for the period by the weighted average number of common shares outstanding during the period using the two class method. Diluted earnings per share is calculated by dividing the net income attributable to common shares for the period by the weighted average number of common and dilutive securities outstanding during the period using the two class method.
Earnings Per Unit of the Operating Partnership [Policy Text Block]	Earnings Per Unit of the Operating Partnership
	Basic earnings per unit is calculated by dividing the net income attributable to common units for the period by the weighted average number of common units outstanding during the period using the two class method. Diluted earnings per unit is calculated by dividing the net income attributable to common units for the period by the weighted average number of common and dilutive securities outstanding during the period
Stock-based Compensation [Policy Text Block]	Stock-based Compensation
	We award stock-based compensation to employees and members of our Board of Directors in the form of common stock. For each stock award granted by DFT, the OP issues an equivalent common unit, which may be referred to herein as a common share, common stock, or a common unit. We estimate the fair value of the awards and recognize this value over the requisite service period. The fair value of restricted stock-based compensation is based on the market value of DFT’s common stock on the date of the grant. The fair value of options to purchase common stock is based on the Black-Scholes model. The fair value of performance units is based on a Monte Carlo simulation.
	Compensation paid with Company common shares, which is included in general and administrative expense on the consolidated statements of operations, totaled $6.2 million, $6.1 million and $7.0 million for the years ended December 31, 2014, 2013 and 2012, respectively. We capitalized $0.7 million, $0.6 million and $0.4 million of compensation paid with Company common shares to our data centers under development for the years ended December 31, 2014, 2013 and 2012, respectively.
New Accounting Pronouncements, Policy [Policy Text Block]	Recently Issued Accounting Pronouncements
	In May 2014, the Financial Accounting Standards Board issued a comprehensive new revenue recognition standard that will supersede nearly all existing revenue recognition guidance under GAAP. The standard’s core principle is that a company will recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which the company expects to be entitled in exchange for those goods or services. We will be required to apply the new standard in the first quarter of 2017 and are assessing whether the new standard will have a material effect on our financial position or results of operations.

2_Significant_Accounting_Polic2

2. Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2014
Accounting Policies [Abstract]
Schedule of Deferred Financing Costs [Table Text Block]	Balances, net of accumulated amortization, at December 31, 2014 and 2013 are as follows (in thousands):
		December 31,
		2014				2013
	Financing costs	$	24,110			$	22,756
	Accumulated amortization	(6,820		)		(4,013		)
	Financing costs, net	$	17,290			$	18,743
Schedule of Leasing Costs Incurred [Table Text Block]	Leasing costs incurred for the years ended December 31, 2014, 2013 and 2012 are as follows:
		Year ended December 31,
		2014				2013			2012
	Costs incurred for new leases	$	2			$	0.9		$	1.3
	Costs incurred for renewals	0.2				1.2			—
	Costs incurred for re-leases	2				—			—
	Total leasing costs incurred	$	4.2			$	2.1		$	1.3
Schedule of Deferred Leasing Costs [Table Text Block]	Balances, net of accumulated amortization, at December 31, 2014 and 2013 are as follows (in thousands):
		December 31,
		2014				2013
	Leasing costs	$	52,358			$	48,312
	Accumulated amortization	(31,153		)		(27,189		)
	Leasing costs, net	$	21,205			$	21,123
Schedule of Lease Intangibles Above and Below Market Value [Table Text Block]	Balances, net of accumulated amortization, at December 31, 2014 and 2013 are as follows (in thousands):
		December 31,
		2014				2013
	Lease contracts above market value	$	23,100			$	23,100
	Accumulated amortization	(15,046		)		(13,946		)
	Lease contracts above market value, net	$	8,054			$	9,154
	Lease contracts below market value	$	39,375			$	39,375
	Accumulated amortization	(32,338		)		(28,845		)
	Lease contracts below market value, net	$	7,037			$	10,530
Redeemable Noncontrolling Interest [Table Text Block]	The following is a summary of activity for redeemable noncontrolling interests – operating partnership for the years ended December 31, 2014, 2013 and 2012 (dollars in thousands):
		OP Units
		Number			Amount
	Balance at December 31, 2011	19,064,381			$	461,739
	Net income attributable to redeemable noncontrolling interests – operating partnership	—			7,803
	Distributions declared	—			(11,683		)
	Redemption of operating partnership units	(277,575	)		(6,800		)
	Adjustments to redeemable noncontrolling interests – operating partnership	—			2,830
	Balance at December 31, 2012	18,786,806			$	453,889
	Net income attributable to redeemable noncontrolling interests – operating partnership	—			5,214
	Distributions declared	—			(15,050		)
	Redemption of operating partnership units	(3,115,269	)		(75,600		)
	Adjustments to redeemable noncontrolling interests – operating partnership	—			18,791
	Balance at December 31, 2013	15,671,537			$	387,244
	Net income attributable to redeemable noncontrolling interests – operating partnership	—			18,704
	Distributions declared	—			(22,831		)
	Redemption of operating partnership units	(234,300	)		(6,100		)
	Adjustments to redeemable noncontrolling interests – operating partnership	—			136,117
	Balance at December 31, 2014	15,437,237			$	513,134
Redeemable Partnership Units [Table Text Block]	The following is a summary of activity for redeemable partnership units for the years ended December 31, 2014, 2013 and 2012 (dollars in thousands):
		OP Units
		Number			Amount
	Balance at December 31, 2011	19,064,381			$	461,739
	Redemption of operating partnership units	(277,575	)		(6,800		)
	Adjustments to redeemable partnership units	—			(1,050		)
	Balance at December 31, 2012	18,786,806			$	453,889
	Redemption of operating partnership units	(3,115,269	)		(75,600		)
	Adjustments to redeemable partnership units	—			8,955
	Balance at December 31, 2013	15,671,537			$	387,244
	Redemption of operating partnership units	(234,300	)		(6,100		)
	Adjustments to redeemable partnership units	—			131,990
	Balance at December 31, 2014	15,437,237			$	513,134
Schedule of Net Income Attributable to Controlling Interests and Transfers From Redeemable Noncontrolling Interests Operating Partnership [Table Text Block]	The following is a summary of net income attributable to controlling interests and transfers to redeemable noncontrolling interests – operating partnership for the years ended December 31, 2014, 2013 and 2012 (dollars in thousands):
		Year ended December 31,
		2014				2013			2012
	Net income attributable to controlling interests	$	105,907			$	48,391		$	53,030
	Transfers from noncontrolling interests:
	Net change in the Company’s common stock and additional paid in capital due to the redemption of OP units and other adjustments to redeemable noncontrolling interests – operating partnership	(130,017		)		56,809			3,970
		$	(24,110	)		$	105,200		$	57,000

3_Real_Estate_Assets_Tables

3. Real Estate Assets (Tables)	12 Months Ended
	Dec. 31, 2014
Real Estate [Abstract]
Schedule of Real Estate Properties [Table Text Block]	The following is a summary of our properties as of December 31, 2014 (dollars in thousands):
	Property	Location		Land		Buildings and		Construction		Total Cost
						Improvements		in Progress
								and Land Held
								for
								Development
	ACC2	Ashburn, VA		$	2,500	$	159,158			$	161,658
	ACC3	Ashburn, VA		1,071		95,926				96,997
	ACC4	Ashburn, VA		6,600		538,551				545,151
	ACC5	Ashburn, VA		6,443		298,521				304,964
	ACC6	Ashburn, VA		5,518		216,697				222,215
	ACC7 Phase I	Ashburn, VA		2,787		92,989				95,776
	VA3	Reston, VA		9,000		178,362				187,362
	VA4	Bristow, VA		6,800		149,250				156,050
	CH1	Elk Grove Village, IL		23,611		358,412				382,023
	NJ1 Phase I	Piscataway, NJ		4,311		210,136				214,447
	SC1 Phase I and IIA	Santa Clara, CA		15,152		325,537				340,689
				83,793		2,623,539		—		2,707,332
	Construction in progress and land held for development	(1	)					358,965		358,965
				$	83,793	$	2,623,539	$	358,965	$	3,066,297
	-1	Properties located in Ashburn, VA (ACC7 Phases II-IV and ACC8); Piscataway, NJ (NJ1 Phase II), Elk Grove Village, IL (CH2) and Santa Clara, CA (SC1 Phase IIB and SC2).
Major Components Of Properties And Useful Lives [Table Text Block]	The following presents the major components of our properties and the useful lives over which they are depreciated.
	Component		Component Life (years)
	Land		N/A
	Building improvements		40
	Electrical infrastructure—power distribution units		20
	Electrical infrastructure—uninterrupted power supply		25
	Electrical infrastructure—switchgear/transformers		30
	Fire protection		40
	Security systems		20
	Mechanical infrastructure—heating, ventilating and air conditioning		20
	Mechanical infrastructure—chiller pumps/building automation		25
	Mechanical infrastructure—chilled water storage and pipes		30

4_Intangible_Assets_and_Liabil1

4. Intangible Assets and Liabilities (Tables)	12 Months Ended
	Dec. 31, 2014
Leasing Costs [Member]
Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block]	As of December 31, 2014, these assets have a weighted average remaining life of 6.8 years with estimated future amortization as follows (in thousands):
	Year Ending December 31,
	2015	$	4,164
	2016	3,817
	2017	3,455
	2018	2,883
	2019	1,810
	2020 and thereafter	5,076
		$	21,205
Lease Contracts [Member]
Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block]	As of December 31, 2014, our net Lease Intangible liabilities have a weighted average remaining life of 8.2 years for above market leases and 3.2 years for below market leases with estimated net future amortization (as an increase (decrease) to rental income) as follows (in thousands):
	Year Ending December 31,
	2015	$	1,966
	2016	412
	2017	174
	2018	(72		)
	2019	(655		)
	2020 and thereafter	(2,842		)
		$	(1,017	)
Tenant Origination Costs [Member]
Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block]	As of December 31, 2014, these assets have a weighted average remaining life of 3.2 years with estimated future amortization as follows (in thousands):
	Year Ending December 31,
	2015	$	2,019
	2016	1,243
	2017	1,243
	2018	747
		$	5,252

5_Leases_Tables

5. Leases (Tables)	12 Months Ended
	Dec. 31, 2014
Leases [Abstract]
Schedule Of Customers Comprising More Than Ten Percent Of Consolidated Revenues [Table Text Block]	For the years ended December 31, 2014, 2013 and 2012, the following customers comprised more than 10.0% of our consolidated revenues:
		Microsoft		Facebook		Rackspace		Yahoo!
	Year ended December 31, 2014	21.6	%	17.4	%	12.4	%	10.9	%
	Year ended December 31, 2013	17.8	%	19.2	%	11.6	%	13	%
	Year ended December 31, 2012	14.9	%	20.7	%	9.3	%	15.5	%
Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block]	As of December 31, 2014, future minimum lease payments to be received under noncancelable operating leases are as follows for the years ending December 31 (in thousands):
	2015	$	288,332
	2016	279,422
	2017	275,328
	2018	246,795
	2019	179,956
	2020 and thereafter	515,883
		$	1,785,716

6_Debt_Tables

6. Debt (Tables)	12 Months Ended
	Dec. 31, 2014
Debt Instrument [Line Items]
Schedule of Debt [Table Text Block]	Debt Summary as of December 31, 2014 and December 31, 2013
	($ in thousands)
		December 31, 2014													December 31, 2013
		Amounts				% of Total			Rates			Maturities			Amounts
												(years)
	Secured	$	115,000			11	%		1.7	%		3.2			$	115,000
	Unsecured	910,000				89	%		4.4	%		5.9			754,000
	Total	$	1,025,000			100	%		4.1	%		5.6			$	869,000
	Fixed Rate Debt:
	Unsecured Notes due 2021	$	600,000			59	%		5.9	%		6.7			$	600,000
	Fixed Rate Debt	600,000				59	%		5.9	%		6.7			600,000
	Floating Rate Debt:
	Unsecured Credit Facility	60,000				6	%		1.7	%		3.4			—
	Unsecured Term Loan	250,000				24	%		1.7	%		4.6			154,000
	ACC3 Term Loan	115,000				11	%		1.7	%		3.2			115,000
	Floating Rate Debt	425,000				41	%		1.7	%		4			269,000
	Total	$	1,025,000			100	%		4.1	%		5.6			$	869,000
Schedule Of Interest Rate Margin Applicable By Indebtedness Level [Table Text Block]
					Applicable Margin
	Pricing Level		Ratio of Total Indebtedness to Gross Asset Value		LIBOR Rate Loans			Base Rate Loans
	Level 1		Less than or equal to 35%		1.85	%		0.85	%
	Level 2		Greater than 35% but less than or equal to 40%		2	%		1	%
	Level 3		Greater than 40% but less than or equal to 45%		2.15	%		1.15	%
	Level 4		Greater than 45% but less than or equal to 52.5%		2.3	%		1.3	%
	Level 5		Greater than 52.5%		2.5	%		1.5	%
Schedule Of Credit Rating Of Unsecured Notes [Table Text Block]
					Applicable Margin
	Credit Rating Level		Credit Rating		LIBOR Rate Loans			Base Rate Loans
	Level 1		Greater than or equal to A- by S&P or A3 by Moody’s		1.05	%		0.05	%
	Level 2		Greater than or equal to BBB+ by S&P or Baa1 by Moody’s		1.2	%		0.2	%
	Level 3		Greater than or equal to BBB by S&P or Baa2 by Moody’s		1.35	%		0.35	%
	Level 4		Greater than or equal to BBB- by S&P or Baa3 by Moody’s		1.5	%		0.5	%
	Level 5		Less than BBB- by S&P or Baa3 by Moody’s		2.1	%		1.1	%
Schedule of Maturities of Long-term Debt [Table Text Block]	A summary of the Company's debt maturity schedule as of December 31, 2014 is as follows:
	Debt Maturity as of December 31, 2014
	($ in thousands)
	Year		Fixed Rate					Floating Rate					Total				% of Total		Rates
	2015		$	—				—					$	—			—		—
	2016		—					3,750			-2		3,750				0.4	%	1.7	%
	2017		—					8,750			-2		8,750				0.8	%	1.7	%
	2018		—					162,500			(2)(3)		162,500				15.9	%	1.7	%
	2019		—					250,000			-4		250,000				24.4	%	1.7	%
	2020		—					—					—				—		—
	2021		600,000			-1		—					600,000				58.5	%	5.9	%
	Total		$	600,000				$	425,000				$	1,025,000			100	%	4.1	%
	-1	The 5.875% Unsecured Notes due 2021 mature on September 15, 2021.
	-2	The ACC3 Term Loan matures on March 27, 2018 with no extension option. Quarterly principal payments of $1.25 million begin on April 1, 2016, increase to $2.5 million on April 1, 2017 and continue through maturity.
	-3	The Unsecured Credit Facility matures on May 13, 2018 with a one-year extension option.
	-4	The Unsecured Term Loan matures on July 21, 2019 with no extension option.
Unsecured Notes due 2021 [Member]
Debt Instrument [Line Items]
Summary Of Maturities And Percentage Of Redemption Price Of Unsecured Notes [Table Text Block]
	Year	Redemption Price
	2016	104.406	%
	2017	102.938	%
	2018	101.469	%
	2019 and thereafter	100	%
Unsecured Term Loan [Member]
Debt Instrument [Line Items]
Schedule Of Term Loan Interest Rate Margin Applicable By Indebtedness Level [Table Text Block] [Table Text Block]
					Applicable Margin
	Pricing Level		Ratio of Total Indebtedness to Gross Asset Value		LIBOR Rate Loans			Base Rate Loans
	Level 1		Less than or equal to 35%		1.75	%		0.75	%
	Level 2		Greater than 35% but less than or equal to 40%		1.9	%		0.9	%
	Level 3		Greater than 40% but less than or equal to 45%		2.05	%		1.05	%
	Level 4		Greater than 45% but less than or equal to 52.5%		2.2	%		1.2	%
	Level 5		Greater than 52.5%		2.4	%		1.4	%
Schedule Of Credit Rating For Unsecured Term Loan [Table Text Block] [Table Text Block]
					Applicable Margin
	Credit Rating Level		Credit Rating		LIBOR Rate Loans			Base Rate Loans
	Level 1		Greater than or equal to A- by S&P or A3 by Moody’s		0.95	%		0	%
	Level 2		Greater than or equal to BBB+ by S&P or Baa1 by Moody’s		1.05	%		0.05	%
	Level 3		Greater than or equal to BBB by S&P or Baa2 by Moody’s		1.2	%		0.2	%
	Level 4		Greater than or equal to BBB- by S&P or Baa3 by Moody’s		1.5	%		0.5	%
	Level 5		Less than BBB- by S&P or Baa3 by Moody’s		1.95	%		0.95	%
Unsecured Term Loan [Member] | After First Amendment [Member]
Debt Instrument [Line Items]
Schedule Of Term Loan Interest Rate Margin Applicable By Indebtedness Level [Table Text Block] [Table Text Block]
					Applicable Margin
	Pricing Level		Ratio of Total Indebtedness to Gross Asset Value		LIBOR Rate Loans			Base Rate Loans
	Level 1		Less than or equal to 35%		1.5	%		0.5	%
	Level 2		Greater than 35% but less than or equal to 40%		1.6	%		0.6	%
	Level 3		Greater than 40% but less than or equal to 45%		1.75	%		0.75	%
	Level 4		Greater than 45% but less than or equal to 52.5%		1.9	%		0.9	%
	Level 5		Greater than 52.5%		2.1	%		1.1	%
Schedule Of Credit Rating For Unsecured Term Loan [Table Text Block] [Table Text Block]
					Applicable Margin
	Credit Rating Level		Credit Rating		LIBOR Rate Loans			Base Rate Loans
	Level 1		Greater than or equal to A- by S&P or A3 by Moody’s		0.825	%		0	%
	Level 2		Greater than or equal to BBB+ by S&P or Baa1 by Moody’s		0.875	%		0	%
	Level 3		Greater than or equal to BBB by S&P or Baa2 by Moody’s		1	%		0	%
	Level 4		Greater than or equal to BBB- by S&P or Baa3 by Moody’s		1.25	%		0.25	%
	Level 5		Less than BBB- by S&P or Baa3 by Moody’s		1.65	%		0.65	%
After Fifth Amendment [Member]
Debt Instrument [Line Items]
Schedule Of Interest Rate Margin Applicable By Indebtedness Level [Table Text Block]
					Applicable Margin
	Pricing Level		Ratio of Total Indebtedness to Gross Asset Value		LIBOR Rate Loans			Base Rate Loans
	Level 1		Less than or equal to 35%		1.55	%		0.55	%
	Level 2		Greater than 35% but less than or equal to 40%		1.65	%		0.65	%
	Level 3		Greater than 40% but less than or equal to 45%		1.8	%		0.8	%
	Level 4		Greater than 45% but less than or equal to 52.5%		1.95	%		0.95	%
	Level 5		Greater than 52.5%		2.15	%		1.15	%
Schedule Of Credit Rating Of Unsecured Notes [Table Text Block]
					Applicable Margin
	Credit Rating Level		Credit Rating		LIBOR Rate Loans			Base Rate Loans
	Level 1		Greater than or equal to A- by S&P or A3 by Moody’s		0.875	%		0	%
	Level 2		Greater than or equal to BBB+ by S&P or Baa1 by Moody’s		0.925	%		0	%
	Level 3		Greater than or equal to BBB by S&P or Baa2 by Moody’s		1.05	%		0.05	%
	Level 4		Greater than or equal to BBB- by S&P or Baa3 by Moody’s		1.3	%		0.3	%
	Level 5		Less than BBB- by S&P or Baa3 by Moody’s		1.7	%		0.7	%

10_Preferred_Stock_Tables

10. Preferred Stock (Tables)	12 Months Ended
	Dec. 31, 2014
Series A Preferred Stock [Member]
Preferred Stock Dividend [Line Items]
Schedule of Preferred Stock Dividend [Table Text Block]
	Record Date	Payment Date	Cash Dividend		Ordinary Taxable Dividend (Unaudited)		Nontaxable Return of Capital Distributions (Unaudited)
	4/5/12	4/16/12	$	0.4921875	$	0.4921875	$	0
	7/6/12	7/16/12	0.4921875		0.4921875		0
	10/5/12	10/15/12	0.4921875		0.4921875		0
	12/28/12	1/15/13	0.4921875		0.4921875		0
			$	1.96875	$	1.96875	$	0
	Record Date	Payment Date	Cash Dividend		Ordinary Taxable Dividend (Unaudited)		Nontaxable Return of Capital Distributions (Unaudited)
	4/5/13	4/15/13	$	0.4921875	$	0.4921875	$	0
	7/5/13	7/15/13	0.4921875		0.4921875		0
	10/4/13	10/15/13	0.4921875		0.4921875		0
	12/27/13	1/15/14	0.4921875		0.4921875		0
			$	1.96875	$	1.96875	$	0
	Record Date	Payment Date	Cash Dividend		Ordinary Taxable Dividend (Unaudited)		Nontaxable Return of Capital Distributions (Unaudited)
	4/4/14	4/15/14	$	0.4921875	$	0.4921875	$	0
	7/3/14	7/15/14	0.4921875		0.4921875		0
	10/3/14	10/15/14	0.4921875		0.4921875		0
	12/30/14	1/15/15	0.4921875		0.4921875		0
			$	1.96875	$	1.96875	$	0
Series B Preferred Stock [Member]
Preferred Stock Dividend [Line Items]
Schedule of Preferred Stock Dividend [Table Text Block]
	Record Date	Payment Date	Cash Dividend		Ordinary Taxable Dividend (Unaudited)		Nontaxable Return of Capital Distributions (Unaudited)
	4/5/12	4/16/12	$	0.4765625	$	0.4765625	$	0
	7/6/12	7/16/12	0.4765625		0.4765625		0
	10/5/12	10/15/12	0.4765625		0.4765625		0
	12/28/12	1/15/13	0.4765625		0.4765625		0
			$	1.90625	$	1.90625	$	0
	Record Date	Payment Date	Cash Dividend		Ordinary Taxable Dividend (Unaudited)		Nontaxable Return of Capital Distributions (Unaudited)
	4/4/14	4/15/14	$	0.4765625	$	0.4765625	$	0
	7/3/14	7/15/14	0.4765625		0.4765625		0
	10/3/14	10/15/14	0.4765625		0.4765625		0
	12/30/14	1/15/15	0.4765625		0.4765625		0
			$	1.90625	$	1.90625	$	0
	Record Date	Payment Date	Cash Dividend		Ordinary Taxable Dividend (Unaudited)		Nontaxable Return of Capital Distributions (Unaudited)
	4/5/13	4/15/13	$	0.4765625	$	0.4765625	$	0
	7/5/13	7/15/13	0.4765625		0.4765625		0
	10/4/13	10/15/13	0.4765625		0.4765625		0
	12/27/13	1/15/14	0.4765625		0.4765625		0
			$	1.90625	$	1.90625	$	0

11_Stockholders_Equity_of_the_1

11. Stockholders Equity of the REIT and Partners Capital of the OP (Tables)	12 Months Ended
	Dec. 31, 2014
Stockholders’ Equity of the REIT and Partners’ Capital of the OP [Abstract]
Schedule Of Common Stock Dividend [Table Text Block]
	Record Date	Payment Date	Cash Dividend		Ordinary Taxable Dividend (Unaudited)		Nontaxable Return of Capital Distributions (Unaudited)
	4/5/12	4/16/12	$	0.12	$	0.12	$	0
	7/6/12	7/16/12	0.15		0.15		0
	10/5/12	10/15/12	0.15		0.15		0
	12/28/12	1/15/13	0.2		0.15		0
			$	0.62	$	0.57	$	0
	Record Date	Payment Date	Cash Dividend		Ordinary Taxable Dividend (Unaudited)		Nontaxable Return of Capital Distributions (Unaudited)
	4/5/13	4/15/13	$	0.2	$	0.172	$	0.028
	7/5/13	7/15/13	0.25		0.214		0.036
	10/4/13	10/15/13	0.25		0.214		0.036
	12/27/13	1/15/14	0.25		0		0
			$	0.95	$	0.6	$	0.1
	Record Date	Payment Date	Cash Dividend		Ordinary Taxable Dividend (Unaudited)		Nontaxable Return of Capital Distributions (Unaudited)
	4/4/14	4/15/14	$	0.35	$	0.35	$	0
	7/3/14	7/15/14	0.35		0.35		0
	10/3/14	10/15/14	0.35		0.35		0
	12/30/14	1/15/15	0.42		0.39		0
			$	1.47	$	1.44	$	0

12_Equity_Compensation_Plan_Ta

12. Equity Compensation Plan (Tables)	12 Months Ended
	Dec. 31, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Schedule of Unvested Restricted Stock Units Roll Forward [Table Text Block]	The following table sets forth the number of unvested shares of restricted stock and the weighted average fair value of these shares at the date of grant:
		Shares of			Weighted Average
		Restricted Stock			Fair Value at
					Date of Grant
	Unvested balance at December 31, 2011	489,329			$	15.31
	Granted	143,191			$	22.66
	Vested	(314,571	)		$	11.6
	Forfeited	(20,030	)		$	22.38
	Unvested balance at December 31, 2012	297,919			$	22.31
	Granted	203,241			$	22.82
	Vested	(162,353	)		$	21.73
	Forfeited	(34,843	)		$	22.86
	Unvested balance at December 31, 2013	303,964			$	22.89
	Granted	149,608			$	25.63
	Vested	(125,798	)		$	23.02
	Forfeited	(3,785	)		$	23.98
	Unvested balance at December 31, 2014	323,989			$	24.1
Schedule of Share-based Compensation, Stock Options, Activity [Table Text Block]	A summary of our stock option activity under the applicable equity incentive plan for the years ended December 31, 2014, 2013 and 2012 is presented in the tables below.
		Number of			Weighted Average
		Options			Exercise Price
	Under option, December 31, 2011	1,902,843			$	13.6
	Granted	341,541			$	22.57
	Exercised	(113,955	)		$	7.62
	Forfeited	(53,648	)		$	22.6
	Under option, December 31, 2012	2,076,781			$	15.17
	Granted	374,214			$	22.62
	Exercised	(250,472	)		$	6.83
	Forfeited	(100,613	)		$	22.83
	Under option, December 31, 2013	2,099,910			$	17.13
	Granted	—			$	—
	Exercised	(507,056	)		$	10.95
	Forfeited	—			$	—
	Under option, December 31, 2014	1,592,854			$	19.09
		Shares Subject			Total Unearned				Weighted Average		Weighted Average
		to Option			Compensation				Vesting Period		Remaining
											Contractual Term
	As of December 31, 2012	2,076,781			$	3.2	million		0.8 years		7.3 years
	As of December 31, 2013	2,099,910			$	1.9	million		0.8 years		6.9 years
	As of December 31, 2014	1,592,854			$	0.7	million		0.5 years		6.2 years
Schedule of Stock Options Roll Forward [Table Text Block]	The following table sets forth the number of unvested options as of December 31, 2014, 2013 and 2012 and the weighted average fair value of these options at the grant date.
		Number of			Weighted Average
		Options			Fair Value
					at Date of Grant
	Unvested balance at December 31, 2011	1,256,478			$	5.63
	Granted	341,541			$	5.79
	Vested	(734,380	)		$	4.18
	Forfeited	(53,648	)		$	6.52
	Unvested balance at December 31, 2012	809,991			$	6.96
	Granted	374,214			$	4.75
	Vested	(399,481	)		$	7.34
	Forfeited	(100,613	)		$	5.55
	Unvested balance at December 31, 2013	684,111			$	5.73
	Granted	—			$	—
	Vested	(381,787	)		$	6.28
	Forfeited	—			$	—
	Unvested balance at December 31, 2014	302,324			$	5.05
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Exercisable [Table Text Block]	The following tables set forth the number of exercisable options as of December 31, 2014, 2013 and 2012 and the weighted average fair value and exercise price of these options at the grant date.
		Number of			Weighted Average
		Options			Fair Value
					at Date of Grant
	Options Exercisable at December 31, 2011	646,365			$	2.61
	Vested	734,380			$	4.18
	Exercised	(113,955	)		$	2.56
	Options Exercisable at December 31, 2012	1,266,790			$	3.52
	Vested	399,481			$	7.34
	Exercised	(250,472	)		$	2.35
	Options Exercisable at December 31, 2013	1,415,799			$	4.81
	Vested	381,787			$	6.28
	Exercised	(507,056	)		$	3.54
	Options Exercisable at December 31, 2014	1,290,530			$	5.74
		Exercisable			Intrinsic Value				Weighted Average				Weighted Average
		Options							Exercise Price				Remaining
													Contractual Term
	As of December 31, 2012	1,266,790			$	17.6	million		$	10.24			6.6 years
	As of December 31, 2013	1,415,799			$	14.7	million		$	14.33			6.1 years
	As of December 31, 2014	1,290,530			$	19.3	million		$	18.27			5.8 years
Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]	The following table summarizes the assumptions used to value the stock options granted and the fair value of these options granted during the years ended December 31, 2013 and 2012.
		2013				2012
	Number of options granted	374,214				341,541
	Exercise price	$	22.62			$	22.57
	Expected term (in years)	5				4
	Expected volatility	34		%		39		%
	Expected annual dividend	4		%		2		%
	Risk-free rate	0.83		%		0.64		%
	Fair value at date of grant	$1.8 million				$2.0 million
Schedule of Share-based Payment Award, Performance Units, Valuation Assumptions [Table Text Block]	The following table summarizes the assumptions used to value, and the resulting fair and maximum values of, the performance units granted during the years ended December 31, 2014, 2013 and 2012.
		2014				2013				2012
	Number of performance units granted	110,441				60,468				61,033
	Expected volatility	30		%		33		%		29		%
	Expected annual dividend	5		%		4		%		2		%
	Risk-free rate	0.74		%		0.4		%		0.43		%
	Performance unit fair value at date of grant	$	33.5			$	25.59			$	28.26
	Total grant fair value at date of grant	$3.7 million				$1.5 million				$1.7 million
	Maximum value of grant on vesting date based on closing price of DFT's stock at the date of grant	$8.5 million				$4.1 million				$4.1 million

13_Earnings_Per_Share_of_the_R1

13. Earnings Per Share of the REIT (Tables)	12 Months Ended
	Dec. 31, 2014
Earnings Per Share [Abstract]
Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]	The following table sets forth the reconciliation of basic and diluted average shares outstanding used in the computation of earnings per share of common stock (in thousands except for share and per share amounts):
		Twelve months ended December 31,
		2014				2013			2012
	Basic and Diluted Shares Outstanding
	Weighted average common shares – basic	65,486,108				64,645,316			62,866,189
	Effect of dilutive securities	600,271				828,723			887,817
	Weighted average common shares – diluted	66,086,379				65,474,039			63,754,006
	Calculation of Earnings per Share – Basic
	Net income attributable to common shares	$	78,662			$	21,146		$	25,977
	Net income allocated to unvested restricted shares	(484		)		(267		)	(188		)
	Net income attributable to common shares, adjusted	78,178				20,879			25,789
	Weighted average common shares – basic	65,486,108				64,645,316			62,866,189
	Earnings per common share – basic	$	1.19			$	0.32		$	0.41
	Calculation of Earnings per Share – Diluted
	Net income attributable to common shares	$	78,178			$	21,146		$	25,977
	Adjustments to redeemable noncontrolling interests	—				55			84
	Adjusted net income available to common shares	78,178				21,201			26,061
	Weighted average common shares – diluted	66,086,379				65,474,039			63,754,006
	Earnings per common share – diluted	$	1.18			$	0.32		$	0.41
Schedule of exclusions from diluted earnings per share/unit [Table Text Block]	The following table sets forth the amount of restricted shares, stock options and performance units that have been excluded from the calculation of diluted earnings per share as their effect would have been antidilutive (in millions):
		Twelve months ended December 31,
		2014			2013			2012
	Restricted Shares	—			—			—
	Stock Options	—			0.6			0.9
	Performance Units	0.1			0.1			0.1

14_Earnings_Per_Unit_of_the_Op1

14. Earnings Per Unit of the Operating Partnership (Tables)	12 Months Ended
	Dec. 31, 2014
Earnings per unit of the Operating Partnership [Line Items]
Schedule of basic and diluted units outstanding [Table Text Block]	The following table sets forth the reconciliation of basic and diluted average shares outstanding used in the computation of earnings per share of common stock (in thousands except for share and per share amounts):
		Twelve months ended December 31,
		2014				2013			2012
	Basic and Diluted Shares Outstanding
	Weighted average common shares – basic	65,486,108				64,645,316			62,866,189
	Effect of dilutive securities	600,271				828,723			887,817
	Weighted average common shares – diluted	66,086,379				65,474,039			63,754,006
	Calculation of Earnings per Share – Basic
	Net income attributable to common shares	$	78,662			$	21,146		$	25,977
	Net income allocated to unvested restricted shares	(484		)		(267		)	(188		)
	Net income attributable to common shares, adjusted	78,178				20,879			25,789
	Weighted average common shares – basic	65,486,108				64,645,316			62,866,189
	Earnings per common share – basic	$	1.19			$	0.32		$	0.41
	Calculation of Earnings per Share – Diluted
	Net income attributable to common shares	$	78,178			$	21,146		$	25,977
	Adjustments to redeemable noncontrolling interests	—				55			84
	Adjusted net income available to common shares	78,178				21,201			26,061
	Weighted average common shares – diluted	66,086,379				65,474,039			63,754,006
	Earnings per common share – diluted	$	1.18			$	0.32		$	0.41
Schedule of exclusions from diluted earnings per share/unit [Table Text Block]	The following table sets forth the amount of restricted shares, stock options and performance units that have been excluded from the calculation of diluted earnings per share as their effect would have been antidilutive (in millions):
		Twelve months ended December 31,
		2014			2013			2012
	Restricted Shares	—			—			—
	Stock Options	—			0.6			0.9
	Performance Units	0.1			0.1			0.1
DuPont Fabros Technology, L.P. [Member]
Earnings per unit of the Operating Partnership [Line Items]
Schedule of basic and diluted units outstanding [Table Text Block]	The following table sets forth the reconciliation of basic and diluted average units outstanding used in the computation of earnings per unit:
		Twelve months ended December 31,
		2014			2013			2012
	Basic and Diluted Units Outstanding
	Weighted average common units – basic (includes redeemable partnership units and units of general and limited partners)	81,053,127			80,580,556			81,750,958
	Effect of dilutive securities	600,271			828,723			887,817
	Weighted average common units – diluted	81,653,398			81,409,279			82,638,775
Schedule of exclusions from diluted earnings per share/unit [Table Text Block]	The following table sets forth the amount of restricted units, stock options and performance units that have been excluded from the calculation of diluted earnings per unit as their effect would have been antidilutive (in millions):
		Twelve months ended December 31,
		2014			2013			2012
	Restricted Units	—			—			—
	Stock Options	—			0.6			0.9
	Performance Units	0.1			0.1			0.1

17_Quarterly_Financial_Informa1

17. Quarterly Financial Information (Tables)	12 Months Ended
	Dec. 31, 2014
Quarterly Financial Information Disclosure [Abstract]
Schedule of Quarterly Financial Information [Table Text Block]
		Three months ended
		December 31, 2014		September 30, 2014			June 30, 2014		March 31, 2014
	Total revenue	$	107,977	$	105,578		$	101,950	$	102,087
	Net income	29,737		30,272			32,958		31,644
	Net income attributable to common shares	18,536		18,960			21,121		20,045
	Net income attributable to common shares per common share-basic	0.28		0.29			0.32		0.3
	Net income attributable to common shares per common share-diluted (1)	0.28		0.29			0.32		0.3
		Three months ended
		December 31, 2013		September 30, 2013			June 30, 2013		March 31, 2013
	Total revenue	$	99,444	$	96,342		$	91,564	$	87,759
	Net income (loss)	21,089		(5,958		)	21,747		16,727
	Net income (loss) attributable to common shares	11,460		(10,228		)	11,971		7,943
	Net income (loss) attributable to common shares per common share-basic (2)	0.18		(0.16		)	0.19		0.12
	Net income (loss) attributable to common shares per common share-diluted	0.18		(0.16		)	0.18		0.12
	(1) Amounts do not equal full year results due to rounding in the second quarter of 2014.
	(2) Amounts do not equal full year results due to rounding and the impact of the loss in the third quarter of 2013.

18_Supplemental_Consolidating_1

18. Supplemental Consolidating Financial Data for Subsidiary Guarantors of the Unsecured Notes (Tables)	12 Months Ended
	Dec. 31, 2014
Supplemental Consolidating Financial Data for Subsidiary Guarantors of the Unsecured Notes [Abstract]
Schedule of Supplemental Consolidating Balance Sheets [Table Text Block]	DUPONT FABROS TECHNOLOGY, L.P.
	SUPPLEMENTAL CONSOLIDATING BALANCE SHEETS
	(in thousands except share data)
		December 31, 2014
		Operating			Subsidiary			Subsidiary			Eliminations			Consolidated
		Partnership			Guarantors			Non-Guarantors						Total
	ASSETS
	Income producing property:
	Land	$	—		$	79,935		$	3,858		$	—		$	83,793
	Buildings and improvements	—			2,427,706			195,833			—			2,623,539
		—			2,507,641			199,691			—			2,707,332
	Less: accumulated depreciation	—			(473,203		)	(31,666		)	—			(504,869		)
	Net income producing property	—			2,034,438			168,025			—			2,202,463
	Construction in progress and land held for development	—			145,229			213,736			—			358,965
	Net real estate	—			2,179,667			381,761			—			2,561,428
	Cash and cash equivalents	21,806			—			3,574			—			25,380
	Rents and other receivables	1,775			5,513			825			—			8,113
	Deferred rent	—			139,542			2,823			—			142,365
	Lease contracts above market value, net	—			8,054			—			—			8,054
	Deferred costs, net	15,957			16,098			6,440			—			38,495
	Investment in affiliates	2,547,049			—			—			(2,547,049		)	—
	Prepaid expenses and other assets	2,865			43,866			1,564			—			48,295
	Total assets	$	2,589,452		$	2,392,740		$	396,987		$	(2,547,049	)	$	2,832,130
	LIABILITIES AND PARTNERS’ CAPITAL
	Liabilities:
	Line of credit	$	60,000		$	—		$	—		$	—		$	60,000
	Mortgage notes payable	—			—			115,000			—			115,000
	Unsecured term loan	250,000			—			—			—			250,000
	Unsecured notes payable	600,000			—			—			—			600,000
	Accounts payable and accrued liabilities	4,432			19,580			2,961			—			26,973
	Construction costs payable	—			4,312			28,637			—			32,949
	Accrued interest payable	10,754			—			5			—			10,759
	Distribution payable	39,981			—			—			—			39,981
	Lease contracts below market value, net	—			7,037			—			—			7,037
	Prepaid rents and other liabilities	28			61,728			3,418			—			65,174
	Total liabilities	965,195			92,657			150,021			—			1,207,873
	Redeemable partnership units	513,134			—			—			—			513,134
	Commitments and contingencies	—			—			—			—			—
	Limited Partners’ Capital:
	Series A cumulative redeemable perpetual preferred units, 7,400,000 issued and outstanding at December 31, 2014	185,000			—			—			—			185,000
	Series B cumulative redeemable perpetual preferred units, 6,650,000 issued and outstanding at December 31, 2014	166,250			—			—			—			166,250
	Common units, 65,189,792 issued and outstanding at December 31, 2014	752,254			2,300,083			246,966			(2,547,049		)	752,254
	General partner’s capital, 662,373 common units issued and outstanding at December 31, 2014	7,619			—			—			—			7,619
	Total partners’ capital	1,111,123			2,300,083			246,966			(2,547,049		)	1,111,123
	Total liabilities & partners’ capital	$	2,589,452		$	2,392,740		$	396,987		$	(2,547,049	)	$	2,832,130
	DUPONT FABROS TECHNOLOGY, L.P.
	SUPPLEMENTAL CONSOLIDATING BALANCE SHEETS
	(in thousands except share data)
		December 31, 2013
		Operating			Subsidiary			Subsidiary			Eliminations			Consolidated
		Partnership			Guarantors			Non-Guarantors						Total
	ASSETS
	Income producing property:
	Land	$	—		$	74,885		$	1,071		$	—		$	75,956
	Buildings and improvements	—			2,318,414			102,572			—			2,420,986
		—			2,393,299			103,643			—			2,496,942
	Less: accumulated depreciation	—			(386,796		)	(26,598		)	—			(413,394		)
	Net income producing property	—			2,006,503			77,045			—			2,083,548
	Construction in progress and land held for development	—			154,404			147,664			—			302,068
	Net real estate	—			2,160,907			224,709			—			2,385,616
	Cash and cash equivalents	32,903			—			1,611			—			34,514
	Rents and other receivables	4,226			3,981			4,467			—			12,674
	Deferred rent	—			144,377			5,661			—			150,038
	Lease contracts above market value, net	—			9,154			—			—			9,154
Deferred costs, net	17,318			16,971			5,577			—			39,866
Investment in affiliates	2,372,121			—			—			(2,372,121		)	—
Prepaid expenses and other assets	2,264			37,331			4,912			—			44,507
Total assets	$	2,428,832		$	2,372,721		$	246,937		$	(2,372,121	)	$	2,676,369
LIABILITIES AND PARTNERS’ CAPITAL
Liabilities:
Line of credit	$	—		$	—		$	—		$	—		$	—
Mortgage notes payable	—			—			115,000			—			115,000
Unsecured term loan	154,000			—			—			—			154,000
Unsecured notes payable	600,000			—			—			—			600,000
Accounts payable and accrued liabilities	3,547			14,582			5,437			—			23,566
Construction costs payable	—			22,670			22,774			—			45,444
Accrued interest payable	9,970			—			13			—			9,983
Distribution payable	25,971			—			—			—			25,971
Lease contracts below market value, net	—			10,530			—			—			10,530
Prepaid rents and other liabilities	45			49,915			6,616			—			56,576
Total liabilities	793,533			97,697			149,840			—			1,041,070
Redeemable partnership units	387,244			—			—			—			387,244
Commitments and contingencies	—			—			—			—			—
Limited Partners’ Capital:
Series A cumulative redeemable perpetual preferred units, 7,400,000 issued and outstanding at December 31, 2013	185,000			—			—			—			185,000
Series B cumulative redeemable perpetual preferred units, 6,650,000 issued and outstanding at December 31, 2013	166,250			—			—			—			166,250
Common units, 64,542,901 issued and outstanding at December 31, 2013	887,695			2,275,024			97,097			(2,372,121		)	887,695
General partner’s capital, 662,373 common units issued and outstanding at December 31, 2013	9,110			—			—			—			9,110
DUPONT FABROS TECHNOLOGY, L.P.
SUPPLEMENTAL CONSOLIDATING BALANCE SHEETS
(in thousands)
(Continued)
	December 31, 2013
	Operating			Subsidiary			Subsidiary			Eliminations			Consolidated
	Partnership			Guarantors			Non-Guarantors						Total
Total partners’ capital	1,248,055			2,275,024			97,097			(2,372,121		)	1,248,055
Total liabilities & partners’ capital	$	2,428,832		$	2,372,721		$	246,937		$	(2,372,121	)	$	2,676,369
Schedule of Supplemental Consolidating Statements of Operations [Table Text Block]
		Year ended December 31, 2014
		Operating			Subsidiary			Subsidiary			Eliminations			Consolidated
		Partnership			Guarantors			Non-Guarantors						Total
	Revenues:
	Base rent	$	17,499		$	267,454		$	18,413		$	(17,650	)	$	285,716
	Recoveries from tenants	—			115,185			9,668			—			124,853
	Other revenues	—			1,657			5,489			(123		)	7,023
	Total revenues	17,499			384,296			33,570			(17,773		)	417,592
	Expenses:
	Property operating costs	—			123,140			11,822			(17,623		)	117,339
	Real estate taxes and insurance	—			13,323			872			—			14,195
	Depreciation and amortization	63			90,770			5,947			—			96,780
	General and administrative	16,159			82			940			—			17,181
	Other expenses	3,508			1,526			4,338			(150		)	9,222
	Total expenses	19,730			228,841			23,919			(17,773		)	254,717
	Operating (loss) income	(2,231		)	155,455			9,651			—			162,875
	Interest income	115			—			1			—			116
	Interest:
	Expense incurred	(41,222		)	4,323			3,200			—			(33,699		)
	Amortization of deferred financing costs	(3,173		)	273			(80		)	—			(2,980		)
	Loss on early extinguishment of debt	(1,701		)	—			—			—			(1,701		)
	Equity in earnings	172,823			—			—			(172,823		)	—
	Net income (loss)	124,611			160,051			12,772			(172,823		)	124,611
	Preferred unit distributions	(27,245		)	—			—			—			(27,245		)
	Net income (loss) attributable to common units	$	97,366		$	160,051		$	12,772		$	(172,823	)	$	97,366
		Year ended December 31, 2013
		Operating			Subsidiary			Subsidiary			Eliminations			Consolidated
		Partnership			Guarantors			Non-Guarantors						Total
	Revenues:
	Base rent	$	15,301		$	248,719		$	17,126		$	(15,451	)	$	265,695
	Recoveries from tenants	—			94,794			9,477			—			104,271
	Other revenues	—			1,668			3,613			(138		)	5,143
	Total revenues	15,301			345,181			30,216			(15,589		)	375,109
	Expenses:
	Property operating costs	198			108,536			10,227			(15,439		)	103,522
	Real estate taxes and insurance	—			13,931			449			—			14,380
	Depreciation and amortization	81			88,556			4,421			—			93,058
	General and administrative	15,605			97			559			—			16,261
	Other expenses	778			304			2,718			(150		)	3,650
	Total expenses	16,662			211,424			18,374			(15,589		)	230,871
	Operating (loss) income	(1,361		)	133,757			11,842			—			144,238
	Interest income	(148		)	20			—			265			137
	Interest:
	Expense incurred	(47,343		)	351			814			(265		)	(46,443		)
	Amortization of deferred financing costs	(3,054		)	(167		)	(128		)	—			(3,349		)
	Loss on early extinguishment of debt	(39,278		)	(1,700		)	—			—			(40,978		)
	Equity in earnings	144,789			—			—			(144,789		)	—
	Net income (loss)	53,605			132,261			12,528			(144,789		)	53,605
	Preferred unit distributions	(27,245		)	—			—			—			(27,245		)
	Net income (loss) attributable to common units	$	26,360		$	132,261		$	12,528		$	(144,789	)	$	26,360
		Year ended December 31, 2012
		Operating			Subsidiary			Subsidiary			Eliminations			Consolidated
		Partnership			Guarantors			Non-Guarantors						Total
	Revenues:
	Base rent	$	13,765		$	218,208		$	18,752		$	(13,915	)	$	236,810
	Recoveries from tenants	—			80,387			10,662			—			91,049
	Other revenues	—			1,378			3,335			(127		)	4,586
	Total revenues	13,765			299,973			32,749			(14,042		)	332,445
	Expenses:
	Property operating costs	—			97,036			11,502			(13,892		)	94,646
	Real estate taxes and insurance	—			12,167			522			—			12,689
	Depreciation and amortization	117			83,902			5,222			—			89,241
	General and administrative	14,531			128			2,365			—			17,024
Other expenses	1,437			3,031			2,601			(150		)	6,919
Total expenses	16,085			196,264			22,212			(14,042		)	220,519
Operating (loss) income	(2,320		)	103,709			10,537			—			111,926
Interest income	432			—			—			(264		)	168
Interest:
Expense incurred	(47,535		)	(420		)	(74		)	264			(47,765		)
Amortization of deferred financing costs	(2,748		)	(760		)	12			—			(3,496		)
Equity in earnings	113,004			—			—			(113,004		)	—
Net income (loss)	60,833			102,529			10,475			(113,004		)	60,833
Preferred unit distributions	(27,053		)	—			—			—			(27,053		)
Net income (loss) attributable to common units	$	33,780		$	102,529		$	10,475		$	(113,004	)	$	33,780
Schedule of Supplemental Consolidating Statements Of Cash Flows [Table Text Block]	DUPONT FABROS TECHNOLOGY, L.P.
	SUPPLEMENTAL CONSOLIDATING STATEMENTS OF CASH FLOWS
	(in thousands)
		Year ended December 31, 2014
		Operating			Subsidiary			Subsidiary			Eliminations			Consolidated
		Partnership			Guarantors			Non-Guarantors						Total
	Cash flow from operating activities
	Net cash (used in) provided by operating activities	$	(40,234	)	$	264,409		$	20,339		$	—		$	244,514
	Cash flow from investing activities
	Investments in real estate – development	(404		)	(111,791		)	(153,179		)	—			(265,374		)
	Land acquisition costs	—			—			—			—			—
	Investments in affiliates	5,654			(146,188		)	140,534			—			—
	Interest capitalized for real estate under development	(10		)	(4,323		)	(5,311		)	—			(9,644		)
	Improvements to real estate	—			(1,850		)	(66		)	—			(1,916		)
	Additions to non-real estate property	(20		)	(257		)	(39		)	—			(316		)
	Net cash provided by (used in) investing activities	5,220			(264,409		)	(18,061		)	—			(277,250		)
	Cash flow from financing activities
	Line of credit:
	Proceeds	60,000			—			—			—			60,000
	Unsecured term loan:
	Proceeds	96,000			—			—			—			96,000
	Payments of financing costs	(3,514		)	—			(315		)	—			(3,829		)
	Issuance of OP units for stock option exercises, net	4,363			—			—			—			4,363
	Distributions	(132,932		)	—			—			—			(132,932		)
	Net cash used in financing activities	23,917			—			(315		)	—			23,602
	Net (decrease) increase in cash and cash equivalents	(11,097		)	—			1,963			—			(9,134		)
	Cash and cash equivalents, beginning	32,903			—			1,611			—			34,514
	Cash and cash equivalents, ending	$	21,806		$	—		$	3,574		$	—		$	25,380
	DUPONT FABROS TECHNOLOGY, L.P.
	SUPPLEMENTAL CONSOLIDATING STATEMENTS OF CASH FLOWS
	(in thousands)
		Year ended December 31, 2013
		Operating			Subsidiary			Subsidiary			Eliminations			Consolidated
		Partnership			Guarantors			Non-Guarantors						Total
	Cash flow from operating activities
	Net cash (used in) provided by operating activities	$	(48,725	)	$	225,903		$	16,583		$	—		$	193,761
	Cash flow from investing activities
	Investments in real estate – development	(9		)	(50,827		)	(78,496		)	—			(129,332		)
	Land acquisition costs	—			—			(14,186		)	—			(14,186		)
	Investments in affiliates	62,508			(28,856		)	(33,652		)	—			—
	Interest capitalized for real estate under development	—			(1,399		)	(2,375		)	—			(3,774		)
	Improvements to real estate	—			(5,513		)	(244		)	—			(5,757		)
	Additions to non-real estate property	(6		)	(65		)	—			—			(71		)
	Net cash provided by (used in) investing activities	62,493			(86,660		)	(128,953		)	—			(153,120		)
	Cash flow from financing activities
	Line of credit:
	Proceeds	102,000			—			—			—			102,000
	Repayments	(120,000		)	—			—			—			(120,000		)
	Mortgage notes payable:
	Proceeds	—			—			115,000			—			115,000
	Lump sum payoffs	—			(138,300		)	—			—			(138,300		)
	Repayments	—			(1,300		)	—			—			(1,300		)
	Unsecured term loan:
	Proceeds	154,000			—			—			—			154,000
	Unsecured notes payable:
	Proceeds	600,000			—			—			—			600,000
	Repayments	(550,000		)	—			—			—			(550,000		)
	Payments of financing costs	(16,419		)	(4		)	(1,700		)	—			(18,123		)
	Payments for early extinguishment of debt	(32,544		)	—			—			—			(32,544		)
	Issuance of OP units for stock option exercises, net	1,711			—			—			—			1,711
	Stock repurchases	(37,792		)	—			—			—			(37,792		)
	Distributions	(100,061		)	—			—			—			(100,061		)
	Net cash provided by (used in) financing activities	895			(139,604		)	113,300			—			(25,409		)
	Net increase (decrease) in cash and cash equivalents	14,663			(361		)	930			—			15,232
Cash and cash equivalents, beginning	18,240			361			681			—			19,282
Cash and cash equivalents, ending	$	32,903		$	—		$	1,611		$	—		$	34,514
	Year ended December 31, 2012
	Operating			Subsidiary			Subsidiary			Eliminations			Consolidated
	Partnership			Guarantors			Non-Guarantors						Total
Cash flow from operating activities
Net cash (used in) provided by operating activities	$	(49,869	)	$	168,236		$	14,396		$	—		$	132,763
Cash flow from investing activities
Investments in real estate – development	(26		)	(84,877		)	(9,850		)	—			(94,753		)
Land Acquisition Costs	—			(3,830		)	—			—			(3,830		)
Investments in affiliates	69,833			(65,480		)	(4,353		)	—			—
Interest capitalized for real estate under development	—			(4,244		)	(190		)	—			(4,434		)
Improvements to real estate	—			(4,395		)	(31		)	—			(4,426		)
Additions to non-real estate property	(19		)	(20		)	(18		)	—			(57		)
Net cash used in investing activities	69,788			(162,846		)	(14,442		)	—			(107,500		)
Cash flow from financing activities
Line of credit:
Proceeds	48,000			—			—			—			48,000
Repayments	(50,000		)	—			—			—			(50,000		)
Mortgage notes payable:
Repayments	—			(5,200		)	—			—			(5,200		)
Payments of financing costs	(2,084		)	(25		)	—			—			(2,109		)
Issuance of preferred units, net of offering costs	62,694			—			—			—			62,694
Issuance of OP units for stock option exercises, net	868			—			—			—			868
Distributions	(70,331		)	—			—			—			(70,331		)
Net cash provided by (used in) financing activities	(10,853		)	(5,225		)	—			—			(16,078		)
Net (decrease) increase in cash and cash equivalents	9,066			165			(46		)	—			9,185
Cash and cash equivalents, beginning	9,174			196			727			—			10,097
Cash and cash equivalents, ending	$	18,240		$	361		$	681		$	—		$	19,282

Schedule_II_Consolidated_Allow1

Schedule II - Consolidated Allowance for Doubtful Accounts (Tables)	12 Months Ended
	Dec. 31, 2014
Valuation and Qualifying Accounts Disclosure [Line Items]
Schedule of Valuation and Qualifying Accounts Disclosure [Text Block]
		Balance at Beginning of Period		Charges to Operations		Net Recovery (Deductions)			Balance at End of Period
	Allowance for doubtful accounts:
	Twelve months ended December 31, 2014	$	3,700	$	4,829	$	(9	)	$	8,520
	Twelve months ended December 31, 2013	2,961		739		—			3,700
	Twelve months ended December 31, 2012	—		2,961		—			2,961
Allowance for Doubtful Accounts [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Schedule of Valuation and Qualifying Accounts Disclosure [Text Block]
		Balance at Beginning of Period		Charges to Operations		Net Recovery (Deductions)			Balance at End of Period
	Allowance for doubtful accounts:
	Twelve months ended December 31, 2014	$	3,700	$	4,829	$	(9	)	$	8,520
	Twelve months ended December 31, 2013	2,961		739		—			3,700
	Twelve months ended December 31, 2012	—		2,961		—			2,961

Schedule_III_Consolidated_Real1

Schedule III - Consolidated Real Estate and Accumulated Depreciation (Tables)	12 Months Ended
	Dec. 31, 2014
Real Estate and Accumulated Depreciation [Line Items]
Schedule Of Real Estate And Accumulated Depreciation [Table Text Block]
			Encum-brances			Initial Cost					Cost Capitalized				Gross Carry Amount at								Accumulated			Year	Year
											Subsequent to Acquisition				December 31, 2014								Depreciation at			Built/	Acquired
																							December 31,			Renovated
						Land			Buildings &		Land		Buildings &		Land			Buildings &			Total		2014
									Improvements				Improvements					Improvements
	Operating Properties
	ACC2 (1)		$	—		$	2,500		$	157,100	$	—	$	2,058	$	2,500		$	159,158		$	161,658	$	(50,035	)	2005	2001
	ACC3 (2)		115,000			1,071			—		—		95,926		1,071		1	95,926		1	96,997		(29,313		)	2006	2001
	ACC4 (1)		—			6,600			506,081		—		32,470		6,600		2	538,551		2	545,151		(137,876		)	2007	2006
	ACC5 (1)		—			6,443			43		—		298,478		6,443		3	298,521		3	304,964		(50,191		)	2009-2010	2007
	ACC6 (1)		—			5,518			214,294		—		2,403		5,518		4	216,697		4	222,215		(20,207		)	2009-2011	2007
	ACC7 Phase I		—			2,787					—		92,989		2,787		4	92,989		4	95,776		(1,315		)	2014	2011
	CH1 (1)		—			22,450			238,746		1,161		119,666		23,611		5	358,412		5	382,023		(57,891		)	2007-2008	2007
	NJ1 Phase I (1)		—			4,311			191,649		—		18,487		4,311		6	210,136		6	214,447		(29,064		)	2008-2010	2007
	SC1 Phase I and IIA (1)		—			15,152			—		—		325,537		15,152		7	325,537		7	340,689		(25,581		)	2008-2014	2007
	VA3 (1)		—			9,000			172,881		—		5,481		9,000		8	178,362		8	187,362		(58,261		)	2003-2004	2003
	VA4 (1)		—			6,800			140,575		—		8,675		6,800		9	149,250		9	156,050		(45,135		)	2005	2005
	Subtotal		115,000			82,632			1,621,369		1,161		1,002,170		83,793			2,623,539			2,707,332		(504,869		)
	Development Properties
	SC1 Phase IIB (1)		—			5,049			95,591		—		—		5,049		8	95,591		8	100,640		—				2007
	ACC7 Phase II to IV		—			6,966			85,384		—		—		6,966		9	85,384		9	92,350		—				2011
	CH2		—			14,393			102,703		—		—		14,393		10	102,703		10	117,096		—				2013
	NJ1 Phase II (1)		—			4,318			34,894		—		—		4,318		11	34,894		11	39,212		—				2007
	ACC8		—			3,785			505		—		—		3,785		12	505		12	4,290		—				2007
	SC2 (1)		—			5,377			—		—		—		5,377		13	—		13	5,377		—				2007
	Subtotal		—			39,888			319,077		—		—		39,888			319,077			358,965		—
	Grand Total (3)		$	115,000		$	122,520		$	1,940,446	$	1,161	$	1,002,170	$	123,681		$	2,942,616		$	3,066,297	$	(504,869	)
	(1) The subsidiaries that own these data centers and development properties are guarantors of the Company's Unsecured Notes and Unsecured Credit Facility.
	(2) The subsidiary that owns this data center is encumbered by the Company's ACC3 Term Loan.
	(3) The aggregate gross cost of the Company's properties for federal income tax purposes was $2,360 million (unaudited) as of December 31, 2014.
Schedule of Reconciliation Of Real Estate Assets and Accumulated Depreciation [Table Text Block]
		2014			2013			2012
	Real estate assets
	Balance, beginning of period	$	2,799,010		$	2,607,630		$	2,507,381
	Additions - property acquisitions	—			14,186			3,830
	Additions - improvements	267,357			177,194			96,419
	Deductions - write offs	(70		)	—			—
	Balance, end of period	$	3,066,297		$	2,799,010		$	2,607,630
	Accumulated depreciation
	Balance, beginning of period	$	413,394		$	325,740		$	242,245
	Additions - depreciation	91,545			87,654			83,495
	Deductions - write offs	(70		)	—			—
	Balance, end of period	$	504,869		$	413,394		$	325,740

1_Description_of_Business_Deta

1. Description of Business (Details)	12 Months Ended
	Dec. 31, 2014
Subsidiary or Equity Method Investee [Line Items]
Limited Liability Company (LLC) or Limited Partnership (LP), Members or Limited Partners, Ownership Interest	81.10%
Limited Liability Company (LLC) or Limited Partnership (LP), Managing Member or General Partner, Ownership Interest	1.00%

2_Significant_Accounting_Polic3

2. Significant Accounting Policies Narrative (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Significant Accounting Policies [Line Items]
Capitalized Interest and Deferred Financing Cost Amortization	$10,200,000	$4,000,000	$4,700,000
Capitalized Internal Leasing And Development Costs	4,500,000	3,300,000	3,100,000
Cash at Bank Held by Parent Company not Part of Operating Partnership	4,200,000
Depreciation	92,300,000	88,600,000	84,600,000
Tenant Origination Cost Amortization	3,100,000	3,100,000	3,100,000
Asset impairment charges	0	0	0
Number of Data Center Properties Held for Sale	0
Repayments of Notes Payable	0	138,300,000	0
Write off of Deferred Debt Issuance Cost	1,701,000	40,978,000	0
Payments for Leasing Costs	4,200,000	2,100,000	1,300,000
Amortization of Deferred Leasing Fees	4,100,000	4,100,000	4,300,000
Fuel Inventory	4,300,000	4,000,000
Account receivable reserve	4,900,000	1,600,000
Deferred Rent Reserve	3,700,000	2,100,000
Increase (Decrease) in Notes Receivables	-1,000,000
Notes Receivable, Gross	6,600,000	5,700,000
Notes Receivable, Net	1,700,000	4,100,000
Income Tax Expense (Benefit)	100,000	0	0
Deferred Tax Assets, Gross	5,500,000	2,500,000
Deferred Tax Liabilities, Gross	6,100,000	2,500,000
Deferred Tax Liabilities, Net	600,000	0
Deferred Income Tax Expense (Benefit)	200,000
Operating Loss Carryforwards	5,500,000
Allocated Share-based Compensation Expense	6,200,000	6,100,000	7,000,000
Employee Service Share-based Compensation, Allocation of Recognized Period Costs, Capitalized Amount	700,000	600,000	400,000
Building and Building Improvements [Member]
Significant Accounting Policies [Line Items]
Property, Plant and Equipment, Useful Life	40 years
Minimum [Member] | Building and Building Improvements [Member]
Significant Accounting Policies [Line Items]
Property, Plant and Equipment, Useful Life	10 years
Minimum [Member] | Personal Property [Member]
Significant Accounting Policies [Line Items]
Property, Plant and Equipment, Useful Life	3 years
Maximum [Member] | Building and Building Improvements [Member]
Significant Accounting Policies [Line Items]
Property, Plant and Equipment, Useful Life	40 years
Maximum [Member] | Personal Property [Member]
Significant Accounting Policies [Line Items]
Property, Plant and Equipment, Useful Life	7 years
Revolving Credit Facility [Member]
Significant Accounting Policies [Line Items]
Write off of Deferred Debt Issuance Cost	300,000
Unsecured Term Loan [Member]
Significant Accounting Policies [Line Items]
Write off of Deferred Debt Issuance Cost	1,400,000
Write Off Of Unamortized Debt Issuance Cost	700,000
Acc Five Term Loan [Member]
Significant Accounting Policies [Line Items]
Repayments of Notes Payable		138,300,000
Write off of Deferred Debt Issuance Cost		1,700,000
Unsecured Notes due 2017 [Member]
Significant Accounting Policies [Line Items]
Write off of Deferred Debt Issuance Cost		6,700,000
Notes Receivable [Member]
Significant Accounting Policies [Line Items]
Provision for Doubtful Accounts	2,400,000
Deferred Rent Receivable [Member]
Significant Accounting Policies [Line Items]
Provision for Doubtful Accounts	1,500,000
Deferred Rent Receivable, Gross	$9,500,000

2_Significant_Accounting_Polic4

2. Significant Accounting Policies Schedule of Deferred Financing Costs (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Significant Accounting Policies [Line Items]
Financing costs	$24,110	$22,756
Accumulated amortization	-6,820	-4,013
Financing costs, net	$17,290	$18,743

2_Significant_Accounting_Polic5

2. Significant Accounting Policies Schedule of Leasing Costs Incurred (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Schedule of Leasing Costs Incurred [Line Items]
Payments for Leasing Costs	$4.20	$2.10	$1.30
Costs incurred for new leases
Schedule of Leasing Costs Incurred [Line Items]
Payments for Leasing Costs	2	0.9	1.3
Costs incurred for renewals
Schedule of Leasing Costs Incurred [Line Items]
Payments for Leasing Costs	0.2	1.2	0
Costs incurred for re-leases
Schedule of Leasing Costs Incurred [Line Items]
Payments for Leasing Costs	$2	$0	$0

2_Significant_Accounting_Polic6

2. Significant Accounting Policies Schedule of Deferred Leasing Costs (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Accounting Policies [Abstract]
Leasing costs	$52,358	$48,312
Accumulated amortization	-31,153	-27,189
Total	$21,205	$21,123

2_Significant_Accounting_Polic7

2. Significant Accounting Policies Schedule of Above and Below Market Lease Intangibles (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Accounting Policies [Abstract]
Lease contracts above market value	$23,100	$23,100
Accumulated amortization	-15,046	-13,946
Lease contracts above market value, net	8,054	9,154
Lease contracts below market value	39,375	39,375
Accumulated amortization	-32,338	-28,845
Lease contracts below market value, net	$7,037	$10,530

2_Significant_Accounting_Polic8

2. Significant Accounting Policies Schedule of Redeemable Noncontrolling Interests - Operating Partnership (Details) (USD $)	12 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Accounting Policies [Abstract]
Beginning Balance, units	15,671,537	18,786,806	19,064,381
Beginning Balance	$387,244	$453,889	$461,739
Net income attributable to redeemable noncontrolling interests - operating partnership	18,704	5,214	7,803
Distributions declared	-22,831	-15,050	-11,683
Redemption of operating partnership units, shares	-234,300	-3,115,269	-277,575
Redemption of operating partnership units	-6,100	-75,600	-6,800
Adjustments to redeemable noncontrolling interests – operating partnership	136,117	18,791	2,830
Ending Balance, units	15,437,237	15,671,537	18,786,806
Ending Balance	$513,134	$387,244	$453,889

2_Significant_Accounting_Polic9

2. Significant Accounting Policies Schedule of Redeemable Partnership Units (Details) (USD $)	12 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Significant Accounting Policies [Line Items]
Beginning Balance, units	15,671,537	18,786,806	19,064,381
Beginning Balance	$387,244	$453,889	$461,739
Redemption of operating partnership units, shares	-234,300	-3,115,269	-277,575
Redemption of operating partnership units	-6,100	-75,600	-6,800
Ending Balance, units	15,437,237	15,671,537	18,786,806
Ending Balance	513,134	387,244	453,889
DuPont Fabros Technology, L.P. [Member]
Significant Accounting Policies [Line Items]
Beginning Balance, units	15,671,537	18,786,806	19,064,381
Beginning Balance	387,244	453,889	461,739
Redemption of operating partnership units, shares	-234,300	-3,115,269	-277,575
Redemption of operating partnership units	-6,100	-75,600	-6,800
Adjustments to redeemable partnership units	131,990	8,955	-1,050
Ending Balance, units	15,437,237	15,671,537	18,786,806
Ending Balance	$513,134	$387,244	$453,889

Recovered_Sheet1

2. Significant Accounting Policies Schedule of Net Income Attributable to Controlling Interests and Transfers to Redeemable Noncontrolling Interests – Operating Partnership (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Accounting Policies [Abstract]
Net income attributable to controlling interests	$105,907	$48,391	$53,030
Net change in the Company’s common stock and additional paid in capital due to the redemption of OP units and other adjustments to redeemable noncontrolling interests – operating partnership	-130,017	56,809	3,970
Net Income Attributable to Controlling Interests and Transfers from Redeemable Noncontrolling Interests Operating Partnership	($24,110)	$105,200	$57,000

3_Real_Estate_Assets_Summary_o

3. Real Estate Assets Summary of Properties (Details) (USD $)	Dec. 31, 2014		Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
In Thousands, unless otherwise specified
Real Estate Assets [Line Items]
Land	$83,793		$75,956
Buildings and improvements	2,623,539		2,420,986
Construction in progress and land held for development	358,965	[1]	302,068
Income producing property	2,707,332		2,496,942
Real Estate, Gross	3,066,297		2,799,010	2,607,630	2,507,381
ACC2 [Member]
Real Estate Assets [Line Items]
Land	2,500
Buildings and improvements	159,158
Construction in progress and land held for development
Income producing property	161,658
ACC3 [Member]
Real Estate Assets [Line Items]
Land	1,071
Buildings and improvements	95,926
Construction in progress and land held for development
Income producing property	96,997
ACC4 [Member]
Real Estate Assets [Line Items]
Land	6,600
Buildings and improvements	538,551
Construction in progress and land held for development
Income producing property	545,151
ACC5 [Member]
Real Estate Assets [Line Items]
Land	6,443
Buildings and improvements	298,521
Construction in progress and land held for development
Income producing property	304,964
ACC6 [Member]
Real Estate Assets [Line Items]
Land	5,518
Buildings and improvements	216,697
Construction in progress and land held for development
Income producing property	222,215
ACC7 Phase I [Member]
Real Estate Assets [Line Items]
Land	2,787
Buildings and improvements	92,989
Construction in progress and land held for development
Income producing property	95,776
VA3 [Member]
Real Estate Assets [Line Items]
Land	9,000
Buildings and improvements	178,362
Construction in progress and land held for development
Income producing property	187,362
VA4 [Member]
Real Estate Assets [Line Items]
Land	6,800
Buildings and improvements	149,250
Construction in progress and land held for development
Income producing property	156,050
CH1 [Member]
Real Estate Assets [Line Items]
Land	23,611
Buildings and improvements	358,412
Construction in progress and land held for development
Income producing property	382,023
NJ1 Phase I [Member]
Real Estate Assets [Line Items]
Land	4,311
Buildings and improvements	210,136
Construction in progress and land held for development
Income producing property	214,447
SC1 Phase I and IIA [Member]
Real Estate Assets [Line Items]
Land	15,152
Buildings and improvements	325,537
Construction in progress and land held for development
Income producing property	$340,689
[1]	(1)Properties located in Ashburn, VA (ACC7 Phases II-IV and ACC8); Piscataway, NJ (NJ1 Phase II), Elk Grove Village, IL (CH2) and Santa Clara, CA (SC1 Phase IIB and SC2).

3_Real_Estate_Assets_Schedule_

3. Real Estate Assets Schedule of Major Components of Properties and Useful Lives (Details)	12 Months Ended
	Dec. 31, 2014
Building Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	40 years
Electrical Structure Power Distribution Units [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	20 years
Electrical Structure Uninterrupted Power Supply [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	25 years
Electrical Structure Switchgear Or Transformers [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	30 years
Fire Protection [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	40 years
Security Systems [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	20 years
Mechanical Structure Heating Ventilating And Air Conditioning [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	20 years
Mechanical Structure Chiller Pumps Or Building Automation [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	25 years
Mechanical Structure Chilled Water Storage And Pipes [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	30 years

4_Intangible_Assets_and_Liabil2

4. Intangible Assets and Liabilities (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Finite-Lived Intangible Assets [Line Items]
Total	$21,205	$21,123
Leasing Costs [Member]
Finite-Lived Intangible Assets [Line Items]
Weighted Average Remaining Life	6 years 292 days
2015	4,164
2016	3,817
2017	3,455
2018	2,883
2019	1,810
2020 and thereafter	5,076
Total	21,205
Lease Contracts
Finite-Lived Intangible Assets [Line Items]
2015	1,966
2016	412
2017	174
2018	-72
2019	-655
2020 and thereafter	-2,842
Total	-1,017
Tenant Origination Costs [Member]
Finite-Lived Intangible Assets [Line Items]
Weighted Average Remaining Life	3 years 73 days
2015	2,019
2016	1,243
2017	1,243
2018	747
Total	$5,252
Above Market Leases [Member]
Finite-Lived Intangible Assets [Line Items]
Weighted Average Remaining Life	8 years 73 days
Below Market Leases [Member]
Finite-Lived Intangible Assets [Line Items]
Weighted Average Remaining Life	3 years 73 days

5_Leases_Details

5. Leases (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
Capital Leased Assets [Line Items]
Deferred rent, net	$142,365,000	$150,038,000
Facebook [Member]
Capital Leased Assets [Line Items]
Deferred rent, net	43,600,000	45,600,000
Prepaid rents	6,400,000	0
Yahoo [Member]
Capital Leased Assets [Line Items]
Deferred rent, net	10,800,000	13,500,000
Prepaid rents	3,800,000	4,000,000
Microsoft [Member]
Capital Leased Assets [Line Items]
Deferred rent, net	-300,000	5,500,000
Prepaid rents	8,300,000	7,100,000
Rackspace [Member]
Capital Leased Assets [Line Items]
Deferred rent, net	35,400,000	30,400,000
Prepaid rents	$0	$3,400,000

5_Leases_Schedule_of_Customers

5. Leases Schedule of Customers Comprising More Than 10% Of Consolidated Revenues (Details)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Facebook [Member]
Property Subject to or Available for Operating Lease [Line Items]
Customers Comprising More Than Ten Percentage Of Consolidated Revenues	0.174	0.192	0.207
Yahoo [Member]
Property Subject to or Available for Operating Lease [Line Items]
Customers Comprising More Than Ten Percentage Of Consolidated Revenues	0.109	0.13	0.155
Microsoft [Member]
Property Subject to or Available for Operating Lease [Line Items]
Customers Comprising More Than Ten Percentage Of Consolidated Revenues	0.216	0.178	0.149
Rackspace [Member]
Property Subject to or Available for Operating Lease [Line Items]
Customers Comprising More Than Ten Percentage Of Consolidated Revenues	0.124	0.116	0.093
Minimum [Member]
Property Subject to or Available for Operating Lease [Line Items]
Customers Comprising More Than Ten Percentage Of Consolidated Revenues		0.1

5_Leases_Schedule_of_Operating

5. Leases Schedule of Operating Lease Future Minimum Lease Payments (Details) (USD $)	Dec. 31, 2014
In Thousands, unless otherwise specified
Schedule of Operating Lease Future Minimum Lease Payments [Line Items]
2015	$288,332
2016	279,422
2017	275,328
2018	246,795
2019	179,956
2020 and thereafter	515,883
Total	$1,785,716

6_Debt_Summary_Details

6. Debt Summary (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Debt Instrument [Line Items]
Mortgage notes payable	$115,000	$115,000
Unsecured Term Loan	250,000	154,000
Long-term Debt	1,025,000	869,000
Unsecured notes payable	600,000	600,000
Line of credit	60,000	0
Total Debt in Percentage	100.00%
Debt, Weighted Average Interest Rate	4.10%
Long Term Debt, Weighted Average Maturity in Years	5.6
Fixed Rate Debt [Member]
Debt Instrument [Line Items]
Long-term Debt, Percentage Bearing Fixed Interest, Amount	600,000	600,000
Percentage of Total Debt	59.00%
Long-term Debt, Percentage Bearing Fixed Interest, Percentage Rate	5.90%
FixedInterestDebtMaturityInYears	6.7
Unsecured Notes due 2021 [Member]
Debt Instrument [Line Items]
Unsecured notes payable	600,000	600,000
Percentage of Total Debt	59.00%
Long-term Debt, Percentage Bearing Fixed Interest, Percentage Rate	5.88%
Unsecured Debt Maturity, in Years	6.7
Floating Rate Debt [Member]
Debt Instrument [Line Items]
Long-term Debt, Percentage Bearing Variable Interest, Amount	425,000	269,000
Percentage of Total Debt	41.00%
Long-term Debt, Percentage Bearing Variable Interest, Percentage Rate	1.70%
VariableInterestDebtMaturityInYears	4
Unsecured Credit Facility [Member]
Debt Instrument [Line Items]
Line of credit	60,000	0
Percentage of Total Debt	6.00%
Long-term Debt, Percentage Bearing Variable Interest, Percentage Rate	1.70%
Unsecured Debt Maturity, in Years	3.4
Unsecured Term Loan [Member]
Debt Instrument [Line Items]
Unsecured Term Loan	250,000	154,000
Percentage of Total Debt	24.00%
Long-term Debt, Percentage Bearing Variable Interest, Percentage Rate	1.70%
Unsecured Debt Maturity, in Years	4.6
AccThreeTermLoan [Member]
Debt Instrument [Line Items]
Term Loan	115,000	115,000
Percentage of Total Debt	11.00%
Long-term Debt, Percentage Bearing Variable Interest, Percentage Rate	1.70%
Secured Debt Maturity, in Years	3.2
Secured Debt [Member]
Debt Instrument [Line Items]
Mortgage notes payable	115,000	115,000
Percentage of Total Debt	11.00%
Long-Term Debt, Secured Interest Rate	1.70%
Secured Debt Maturity, in Years	3.2
Unsecured Debt [Member]
Debt Instrument [Line Items]
Unsecured Term Loan	$910,000	$754,000
Percentage of Total Debt	89.00%
Long-Term Debt, Unsecured Interest Rate	4.40%
Unsecured Debt Maturity, in Years	5.9

6_Debt_ACC3_Term_Loan_Details

6. Debt ACC3 Term Loan (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Debt Instrument [Line Items]
Mortgage notes payable	$115,000,000	$115,000,000
AccThreeTermLoan [Member]
Debt Instrument [Line Items]
Debt Instrument, Issuance Date	27-Mar-13
Debt Instrument Amendment Date	9-May-14
Mortgage notes payable	115,000,000
AccThreeTermLoan [Member] | Libor Rate Loans [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.55%
AccThreeTermLoan [Member] | Base Rate Loans [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	0.55%
Maximum [Member] | AccThreeTermLoan [Member]
Debt Instrument [Line Items]
Ratio of Total Indebtedness To Gross Assets Value	60.00%
Minimum [Member] | AccThreeTermLoan [Member]
Debt Instrument [Line Items]
Fixed Charge Coverage Ratio	1.7
Tangible Net Worth Amount	$1,300,000,000
Percentage Of Equity Offerings And Interests In Operating Partnerships To Be Added To Tangible Net Worth Threshold	80.00%
Debt Service Coverage Ratio	1.5
Prior to First Amendment [Member] | AccThreeTermLoan [Member] | Libor Rate Loans [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.85%
Prior to First Amendment [Member] | AccThreeTermLoan [Member] | Base Rate Loans [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	0.85%
AccThreeTermLoan [Member]
Debt Instrument [Line Items]
Debt Instrument, Maturity Date	27-Mar-18

6_Debt_Unsecured_Term_Loan_Det

6. Debt Unsecured Term Loan (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Debt Instrument [Line Items]
Unsecured Term Loan	$250,000,000	$154,000,000
Write off of Deferred Debt Issuance Cost	1,701,000	40,978,000	0
Unsecured Term Loan [Member]
Debt Instrument [Line Items]
Debt Instrument, Issuance Date	13-Sep-13
Unsecured Term Loan	195,000,000	154,000,000
Debt Instrument, Maturity Date	15-Feb-19
Delayed Draw Deadline	10-Jan-14
Unsecured Term Loan Accordion Increase Amount	55,000,000
Accordion Exercise Date	18-Oct-13
Unsecured Term Loan with Accordion	250,000,000
Unsecured Term Loan Remaining Balance To Be Drawn Including Accordion	96,000,000
Write off of Deferred Debt Issuance Cost	1,400,000
Write Off Of Unamortized Debt Issuance Cost	700,000
Unsecured Term Loan [Member] | After First Amendment [Member]
Debt Instrument [Line Items]
Debt Instrument, Maturity Date	21-Jul-19
Maximum [Member] | Unsecured Term Loan [Member]
Debt Instrument [Line Items]
Unsecured Debt To Unencumbered Assets	60.00%
Ratio of Total Indebtedness To Gross Assets Value	60.00%
Minimum [Member] | Unsecured Term Loan [Member]
Debt Instrument [Line Items]
Income from Unencumbered Assets To Unsecured Debt	12.50%
Fixed Charge Coverage Ratio	1.7
Tangible Net Worth Amount	$1,300,000,000
Percentage Of Equity Offerings And Interests In Operating Partnerships To Be Added To Tangible Net Worth Threshold	80.00%

6_Debt_Applicable_Margin_of_Un

6. Debt Applicable Margin of Unsecured Term Loan (Details) (Unsecured Term Loan [Member])	12 Months Ended
	Dec. 31, 2014
Pricing Level 1 [Member] | Libor Rate Loans [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.75%
Pricing Level 1 [Member] | Libor Rate Loans [Member] | After First Amendment [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.50%
Pricing Level 1 [Member] | Base Rate Loans [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	0.75%
Pricing Level 1 [Member] | Base Rate Loans [Member] | After First Amendment [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	0.50%
Pricing Level 2 [Member] | Libor Rate Loans [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.90%
Pricing Level 2 [Member] | Libor Rate Loans [Member] | After First Amendment [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.60%
Pricing Level 2 [Member] | Base Rate Loans [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	0.90%
Pricing Level 2 [Member] | Base Rate Loans [Member] | After First Amendment [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	0.60%
Pricing Level 3 [Member] | Libor Rate Loans [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	2.05%
Pricing Level 3 [Member] | Libor Rate Loans [Member] | After First Amendment [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.75%
Pricing Level 3 [Member] | Base Rate Loans [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.05%
Pricing Level 3 [Member] | Base Rate Loans [Member] | After First Amendment [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	0.75%
Pricing Level 4 [Member] | Libor Rate Loans [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	2.20%
Pricing Level 4 [Member] | Libor Rate Loans [Member] | After First Amendment [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.90%
Pricing Level 4 [Member] | Base Rate Loans [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.20%
Pricing Level 4 [Member] | Base Rate Loans [Member] | After First Amendment [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	0.90%
Pricing Level 5 [Member] | Libor Rate Loans [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	2.40%
Pricing Level 5 [Member] | Libor Rate Loans [Member] | After First Amendment [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	2.10%
Pricing Level 5 [Member] | Base Rate Loans [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.40%
Pricing Level 5 [Member] | Base Rate Loans [Member] | After First Amendment [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.10%
Maximum [Member]
Debt Instrument [Line Items]
Ratio of Total Indebtedness To Gross Assets Value	60.00%
Maximum [Member] | Pricing Level 1 [Member]
Debt Instrument [Line Items]
Ratio of Total Indebtedness To Gross Assets Value	35.00%
Maximum [Member] | Pricing Level 1 [Member] | After First Amendment [Member]
Debt Instrument [Line Items]
Ratio of Total Indebtedness To Gross Assets Value	35.00%
Maximum [Member] | Pricing Level 2 [Member]
Debt Instrument [Line Items]
Ratio of Total Indebtedness To Gross Assets Value	40.00%
Maximum [Member] | Pricing Level 2 [Member] | After First Amendment [Member]
Debt Instrument [Line Items]
Ratio of Total Indebtedness To Gross Assets Value	40.00%
Maximum [Member] | Pricing Level 3 [Member]
Debt Instrument [Line Items]
Ratio of Total Indebtedness To Gross Assets Value	45.00%
Maximum [Member] | Pricing Level 3 [Member] | After First Amendment [Member]
Debt Instrument [Line Items]
Ratio of Total Indebtedness To Gross Assets Value	45.00%
Maximum [Member] | Pricing Level 4 [Member]
Debt Instrument [Line Items]
Ratio of Total Indebtedness To Gross Assets Value	52.50%
Maximum [Member] | Pricing Level 4 [Member] | After First Amendment [Member]
Debt Instrument [Line Items]
Ratio of Total Indebtedness To Gross Assets Value	52.50%
Minimum [Member] | Pricing Level 2 [Member]
Debt Instrument [Line Items]
Ratio of Total Indebtedness To Gross Assets Value	35.00%
Minimum [Member] | Pricing Level 2 [Member] | After First Amendment [Member]
Debt Instrument [Line Items]
Ratio of Total Indebtedness To Gross Assets Value	35.00%
Minimum [Member] | Pricing Level 3 [Member]
Debt Instrument [Line Items]
Ratio of Total Indebtedness To Gross Assets Value	40.00%
Minimum [Member] | Pricing Level 3 [Member] | After First Amendment [Member]
Debt Instrument [Line Items]
Ratio of Total Indebtedness To Gross Assets Value	40.00%
Minimum [Member] | Pricing Level 4 [Member]
Debt Instrument [Line Items]
Ratio of Total Indebtedness To Gross Assets Value	45.00%
Minimum [Member] | Pricing Level 4 [Member] | After First Amendment [Member]
Debt Instrument [Line Items]
Ratio of Total Indebtedness To Gross Assets Value	45.00%
Minimum [Member] | Pricing Level 5 [Member]
Debt Instrument [Line Items]
Ratio of Total Indebtedness To Gross Assets Value	52.50%
Minimum [Member] | Pricing Level 5 [Member] | After First Amendment [Member]
Debt Instrument [Line Items]
Ratio of Total Indebtedness To Gross Assets Value	52.50%

6_Debt_Credit_Rating_for_Unsec

6. Debt Credit Rating for Unsecured Term Loan (Details) (Unsecured Term Loan [Member])	12 Months Ended
	Dec. 31, 2014
Credit Rating Level 1 [Member] | Greaten than A- S&P, Moody's A3 Rating [Member] | Libor Rate Loans [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	0.95%
Credit Rating Level 1 [Member] | Greaten than A- S&P, Moody's A3 Rating [Member] | Libor Rate Loans [Member] | After First Amendment [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	0.83%
Credit Rating Level 1 [Member] | Greaten than A- S&P, Moody's A3 Rating [Member] | Base Rate Loans [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	0.00%
Credit Rating Level 1 [Member] | Greaten than A- S&P, Moody's A3 Rating [Member] | Base Rate Loans [Member] | After First Amendment [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	0.00%
Credit Rating Level 2 [Member] | Greater than BBB plus S&P, Moody's Baa1 Rating [Member] | Libor Rate Loans [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.05%
Credit Rating Level 2 [Member] | Greater than BBB plus S&P, Moody's Baa1 Rating [Member] | Libor Rate Loans [Member] | After First Amendment [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	0.88%
Credit Rating Level 2 [Member] | Greater than BBB plus S&P, Moody's Baa1 Rating [Member] | Base Rate Loans [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	0.05%
Credit Rating Level 2 [Member] | Greater than BBB plus S&P, Moody's Baa1 Rating [Member] | Base Rate Loans [Member] | After First Amendment [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	0.00%
Credit Rating Level 3 [Member] | Greater than BBB S&P, Moody's Baa2 Rating [Member] | Libor Rate Loans [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.20%
Credit Rating Level 3 [Member] | Greater than BBB S&P, Moody's Baa2 Rating [Member] | Libor Rate Loans [Member] | After First Amendment [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.00%
Credit Rating Level 3 [Member] | Greater than BBB S&P, Moody's Baa2 Rating [Member] | Base Rate Loans [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	0.20%
Credit Rating Level 3 [Member] | Greater than BBB S&P, Moody's Baa2 Rating [Member] | Base Rate Loans [Member] | After First Amendment [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	0.00%
Credit Rating Level 4 [Member] | Greater than BBB- S&P, Moody's Baa3 Rating [Member] | Libor Rate Loans [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.50%
Credit Rating Level 4 [Member] | Greater than BBB- S&P, Moody's Baa3 Rating [Member] | Libor Rate Loans [Member] | After First Amendment [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.25%
Credit Rating Level 4 [Member] | Greater than BBB- S&P, Moody's Baa3 Rating [Member] | Base Rate Loans [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	0.50%
Credit Rating Level 4 [Member] | Greater than BBB- S&P, Moody's Baa3 Rating [Member] | Base Rate Loans [Member] | After First Amendment [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	0.25%
Credit Rating Level 5 [Member] | Less than BBB- S&P, Moody's Baa3 Rating [Member] | Libor Rate Loans [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.95%
Credit Rating Level 5 [Member] | Less than BBB- S&P, Moody's Baa3 Rating [Member] | Libor Rate Loans [Member] | After First Amendment [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.65%
Credit Rating Level 5 [Member] | Less than BBB- S&P, Moody's Baa3 Rating [Member] | Base Rate Loans [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	0.95%
Credit Rating Level 5 [Member] | Less than BBB- S&P, Moody's Baa3 Rating [Member] | Base Rate Loans [Member] | After First Amendment [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	0.65%

6_Debt_Unsecured_Notes_due_202

6. Debt Unsecured Notes due 2021 (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Debt Instrument [Line Items]
Unsecured notes payable	$600,000	$600,000
Unsecured Notes due 2021 [Member]
Debt Instrument [Line Items]
Debt Instrument, Issuance Date	24-Sep-13
Unsecured notes payable	$600,000	$600,000
Long-term Debt, Percentage Bearing Fixed Interest, Percentage Rate	5.88%
Debt Instrument, Maturity Date	15-Sep-21
First Semiannual Interest Payment Term	March 15th
Second Semiannual Interest Payment Term	September 15th
Unencumbered Assets to Unsecured Debt	150.00%
Unsecured Notes due 2021 [Member] | Prior to September Fifteen Two Thousand Sixteen [Member]
Debt Instrument [Line Items]
Percentage Of Principal Amount At Which Unsecured Notes May Be Redeemed	100.00%
Unsecured Notes due 2021 [Member] | Change in control [Member]
Debt Instrument [Line Items]
Percentage Of Principal Amount At Which Unsecured Notes May Be Redeemed	101.00%
Unsecured Notes due 2021 [Member] | Asset Sales [Member]
Debt Instrument [Line Items]
Percentage Of Principal Amount At Which Unsecured Notes May Be Redeemed	100.00%

6_Debt_Summary_Of_Maturities_A

6. Debt Summary Of Maturities And Percentage Of Redemption Price Of Unsecured Notes (Details) (Unsecured Notes due 2021 [Member])	Dec. 31, 2014
2016
Debt Instrument [Line Items]
Redemption Price	104.41%
2017
Debt Instrument [Line Items]
Redemption Price	102.94%
2018
Debt Instrument [Line Items]
Redemption Price	101.47%
2019 and thereafter
Debt Instrument [Line Items]
Redemption Price	100.00%

6_Debt_Unsecured_Credit_Facili

6. Debt Unsecured Credit Facility (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Feb. 25, 2015
Debt Instrument [Line Items]
Write off of Deferred Debt Issuance Cost	$1,701,000	$40,978,000	$0
Line of credit	60,000,000	0
Unsecured Credit Facility [Member]
Debt Instrument [Line Items]
Line Of Credit Capacity Prior To Fifth Amendment	400,000,000
Debt Instrument Maturity Date Prior to Fifth Amendment	21-Mar-16
Extension Option On Debt Maturity Years	1
Basis Points Extension Fee On Total Commitment	25
Line Of Credit Commitment If Increased	600,000,000
After Fifth Amendment [Member] | Unsecured Credit Facility [Member]
Debt Instrument [Line Items]
Debt Instrument Amendment Date	13-May-14
Line of Credit Facility, Maximum Borrowing Capacity	560,000,000
Debt Instrument, Maturity Date	13-May-18
Extension Option On Debt Maturity Years	1
Basis Points Extension Fee On Total Commitment	15
Write off of Deferred Debt Issuance Cost	-300,000
Line Of Credit Commitment If Increased	800,000,000
Facility amount available for Letters of Credit	35,000,000
Letters of Credit Outstanding, Amount	100,000
Line of credit	60,000,000
After Fifth Amendment [Member] | Maximum [Member] | Unsecured Credit Facility [Member]
Debt Instrument [Line Items]
Unsecured Debt To Unencumbered Assets	60.00%
Ratio of Total Indebtedness To Gross Assets Value	60.00%
After Fifth Amendment [Member] | Minimum [Member] | Unsecured Credit Facility [Member]
Debt Instrument [Line Items]
Income from Unencumbered Assets To Unsecured Debt	12.50%
Fixed Charge Coverage Ratio	1.7
Tangible Net Worth Amount	1,300,000,000
Percentage Of Equity Offerings And Interests In Operating Partnerships To Be Added To Tangible Net Worth Threshold	80.00%
Subsequent Event [Member] | After Fifth Amendment [Member] | Unsecured Credit Facility [Member]
Debt Instrument [Line Items]
Line of credit				$120,000,000

6_Debt_Applicable_Margin_of_Un1

6. Debt Applicable Margin of Unsecured Credit Facility (Details) (Unsecured Credit Facility [Member])	12 Months Ended
	Dec. 31, 2014
Pricing Level 1 [Member] | Libor Rate Loans [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.85%
Pricing Level 1 [Member] | Base Rate Loans [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	0.85%
Pricing Level 1 [Member] | Maximum [Member]
Debt Instrument [Line Items]
Ratio of Total Indebtedness To Gross Assets Value	35.00%
Pricing Level 2 [Member] | Libor Rate Loans [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	2.00%
Pricing Level 2 [Member] | Base Rate Loans [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.00%
Pricing Level 2 [Member] | Maximum [Member]
Debt Instrument [Line Items]
Ratio of Total Indebtedness To Gross Assets Value	40.00%
Pricing Level 2 [Member] | Minimum [Member]
Debt Instrument [Line Items]
Ratio of Total Indebtedness To Gross Assets Value	35.00%
Pricing Level 3 [Member] | Libor Rate Loans [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	2.15%
Pricing Level 3 [Member] | Base Rate Loans [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.15%
Pricing Level 3 [Member] | Maximum [Member]
Debt Instrument [Line Items]
Ratio of Total Indebtedness To Gross Assets Value	45.00%
Pricing Level 3 [Member] | Minimum [Member]
Debt Instrument [Line Items]
Ratio of Total Indebtedness To Gross Assets Value	40.00%
Pricing Level 4 [Member] | Libor Rate Loans [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	2.30%
Pricing Level 4 [Member] | Base Rate Loans [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.30%
Pricing Level 4 [Member] | Maximum [Member]
Debt Instrument [Line Items]
Ratio of Total Indebtedness To Gross Assets Value	52.50%
Pricing Level 4 [Member] | Minimum [Member]
Debt Instrument [Line Items]
Ratio of Total Indebtedness To Gross Assets Value	45.00%
Pricing Level 5 [Member] | Libor Rate Loans [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	2.50%
Pricing Level 5 [Member] | Base Rate Loans [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.50%
Pricing Level 5 [Member] | Minimum [Member]
Debt Instrument [Line Items]
Ratio of Total Indebtedness To Gross Assets Value	52.50%
After Fifth Amendment [Member] | Maximum [Member]
Debt Instrument [Line Items]
Ratio of Total Indebtedness To Gross Assets Value	60.00%
After Fifth Amendment [Member] | Pricing Level 1 [Member] | Libor Rate Loans [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.55%
After Fifth Amendment [Member] | Pricing Level 1 [Member] | Base Rate Loans [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	0.55%
After Fifth Amendment [Member] | Pricing Level 1 [Member] | Maximum [Member]
Debt Instrument [Line Items]
Ratio of Total Indebtedness To Gross Assets Value	35.00%
After Fifth Amendment [Member] | Pricing Level 2 [Member] | Libor Rate Loans [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.65%
After Fifth Amendment [Member] | Pricing Level 2 [Member] | Base Rate Loans [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	0.65%
After Fifth Amendment [Member] | Pricing Level 2 [Member] | Maximum [Member]
Debt Instrument [Line Items]
Ratio of Total Indebtedness To Gross Assets Value	40.00%
After Fifth Amendment [Member] | Pricing Level 2 [Member] | Minimum [Member]
Debt Instrument [Line Items]
Ratio of Total Indebtedness To Gross Assets Value	35.00%
After Fifth Amendment [Member] | Pricing Level 3 [Member] | Libor Rate Loans [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.80%
After Fifth Amendment [Member] | Pricing Level 3 [Member] | Base Rate Loans [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	0.80%
After Fifth Amendment [Member] | Pricing Level 3 [Member] | Maximum [Member]
Debt Instrument [Line Items]
Ratio of Total Indebtedness To Gross Assets Value	45.00%
After Fifth Amendment [Member] | Pricing Level 3 [Member] | Minimum [Member]
Debt Instrument [Line Items]
Ratio of Total Indebtedness To Gross Assets Value	40.00%
After Fifth Amendment [Member] | Pricing Level 4 [Member] | Libor Rate Loans [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.95%
After Fifth Amendment [Member] | Pricing Level 4 [Member] | Base Rate Loans [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	0.95%
After Fifth Amendment [Member] | Pricing Level 4 [Member] | Maximum [Member]
Debt Instrument [Line Items]
Ratio of Total Indebtedness To Gross Assets Value	52.50%
After Fifth Amendment [Member] | Pricing Level 4 [Member] | Minimum [Member]
Debt Instrument [Line Items]
Ratio of Total Indebtedness To Gross Assets Value	45.00%
After Fifth Amendment [Member] | Pricing Level 5 [Member] | Libor Rate Loans [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	2.15%
After Fifth Amendment [Member] | Pricing Level 5 [Member] | Base Rate Loans [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.15%
After Fifth Amendment [Member] | Pricing Level 5 [Member] | Minimum [Member]
Debt Instrument [Line Items]
Ratio of Total Indebtedness To Gross Assets Value	52.50%

6_Debt_Credit_Rating_for_Unsec1

6. Debt Credit Rating for Unsecured Credit Facility (Details) (Unsecured Credit Facility [Member])	12 Months Ended
	Dec. 31, 2014
Credit Rating Level 1 [Member] | Greaten than A- S&P, Moody's A3 Rating [Member] | Libor Rate Loans [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.05%
Credit Rating Level 1 [Member] | Greaten than A- S&P, Moody's A3 Rating [Member] | Base Rate Loans [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	0.05%
Credit Rating Level 2 [Member] | Greater than BBB plus S&P, Moody's Baa1 Rating [Member] | Libor Rate Loans [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.20%
Credit Rating Level 2 [Member] | Greater than BBB plus S&P, Moody's Baa1 Rating [Member] | Base Rate Loans [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	0.20%
Credit Rating Level 3 [Member] | Greater than BBB S&P, Moody's Baa2 Rating [Member] | Libor Rate Loans [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.35%
Credit Rating Level 3 [Member] | Greater than BBB S&P, Moody's Baa2 Rating [Member] | Base Rate Loans [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	0.35%
Credit Rating Level 4 [Member] | Greater than BBB- S&P, Moody's Baa3 Rating [Member] | Libor Rate Loans [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.50%
Credit Rating Level 4 [Member] | Greater than BBB- S&P, Moody's Baa3 Rating [Member] | Base Rate Loans [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	0.50%
Credit Rating Level 5 [Member] | Less than BBB- S&P, Moody's Baa3 Rating [Member] | Libor Rate Loans [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	2.10%
Credit Rating Level 5 [Member] | Less than BBB- S&P, Moody's Baa3 Rating [Member] | Base Rate Loans [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.10%
After Fifth Amendment [Member] | Credit Rating Level 1 [Member] | Greaten than A- S&P, Moody's A3 Rating [Member] | Libor Rate Loans [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	0.88%
After Fifth Amendment [Member] | Credit Rating Level 1 [Member] | Greaten than A- S&P, Moody's A3 Rating [Member] | Base Rate Loans [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	0.00%
After Fifth Amendment [Member] | Credit Rating Level 2 [Member] | Greater than BBB plus S&P, Moody's Baa1 Rating [Member] | Libor Rate Loans [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	0.93%
After Fifth Amendment [Member] | Credit Rating Level 2 [Member] | Greater than BBB plus S&P, Moody's Baa1 Rating [Member] | Base Rate Loans [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	0.00%
After Fifth Amendment [Member] | Credit Rating Level 3 [Member] | Greater than BBB S&P, Moody's Baa2 Rating [Member] | Libor Rate Loans [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.05%
After Fifth Amendment [Member] | Credit Rating Level 3 [Member] | Greater than BBB S&P, Moody's Baa2 Rating [Member] | Base Rate Loans [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	0.05%
After Fifth Amendment [Member] | Credit Rating Level 4 [Member] | Greater than BBB- S&P, Moody's Baa3 Rating [Member] | Libor Rate Loans [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.30%
After Fifth Amendment [Member] | Credit Rating Level 4 [Member] | Greater than BBB- S&P, Moody's Baa3 Rating [Member] | Base Rate Loans [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	0.30%
After Fifth Amendment [Member] | Credit Rating Level 5 [Member] | Less than BBB- S&P, Moody's Baa3 Rating [Member] | Libor Rate Loans [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.70%
After Fifth Amendment [Member] | Credit Rating Level 5 [Member] | Less than BBB- S&P, Moody's Baa3 Rating [Member] | Base Rate Loans [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	0.70%

6_Debt_Maturity_Summary_Detail

6. Debt Maturity Summary (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013
Debt Instrument [Line Items]
Long-term Debt	1,025,000		$869,000
Total Debt in Percentage	100.00%
Debt, Weighted Average Interest Rate	4.10%
Unsecured Term Loan [Member]
Debt Instrument [Line Items]
Debt Instrument, Maturity Date	15-Feb-19
2015 [Member]
Debt Instrument [Line Items]
Debt Instrument, Periodic Payment, Principal	0
Percentage of Total Debt	0.00%
Debt, Weighted Average Interest Rate	0.00%
2016 [Member]
Debt Instrument [Line Items]
Debt Instrument, Periodic Payment, Principal	3,750
Percentage of Total Debt	0.40%
Debt, Weighted Average Interest Rate	1.70%
2017 [Member]
Debt Instrument [Line Items]
Debt Instrument, Periodic Payment, Principal	8,750
Percentage of Total Debt	0.80%
Debt, Weighted Average Interest Rate	1.70%
2018 [Member]
Debt Instrument [Line Items]
Debt Instrument, Periodic Payment, Principal	162,500
Percentage of Total Debt	15.90%
Debt, Weighted Average Interest Rate	1.70%
2019 [Member]
Debt Instrument [Line Items]
Debt Instrument, Periodic Payment, Principal	250,000
Percentage of Total Debt	24.40%
Debt, Weighted Average Interest Rate	1.70%
2020 [Member]
Debt Instrument [Line Items]
Debt Instrument, Periodic Payment, Principal	0
Percentage of Total Debt	0.00%
Debt, Weighted Average Interest Rate	0.00%
2021 [Member]
Debt Instrument [Line Items]
Debt Instrument, Periodic Payment, Principal	600,000
Percentage of Total Debt	58.50%
Debt, Weighted Average Interest Rate	5.90%
Unsecured Notes due 2021 [Member]
Debt Instrument [Line Items]
Long-term Debt, Percentage Bearing Fixed Interest, Percentage Rate	5.88%
Percentage of Total Debt	59.00%
Debt Instrument, Maturity Date	15-Sep-21
Fixed Rate Debt [Member]
Debt Instrument [Line Items]
Long-term Debt, Percentage Bearing Fixed Interest, Percentage Rate	5.90%
Long-term Debt, Percentage Bearing Fixed Interest, Amount	600,000		600,000
Percentage of Total Debt	59.00%
Fixed Rate Debt [Member] | 2015 [Member]
Debt Instrument [Line Items]
Debt Instrument, Periodic Payment, Principal	0
Fixed Rate Debt [Member] | 2016 [Member]
Debt Instrument [Line Items]
Debt Instrument, Periodic Payment, Principal	0
Fixed Rate Debt [Member] | 2017 [Member]
Debt Instrument [Line Items]
Debt Instrument, Periodic Payment, Principal	0
Fixed Rate Debt [Member] | 2018 [Member]
Debt Instrument [Line Items]
Debt Instrument, Periodic Payment, Principal	0
Fixed Rate Debt [Member] | 2019 [Member]
Debt Instrument [Line Items]
Debt Instrument, Periodic Payment, Principal	0
Fixed Rate Debt [Member] | 2020 [Member]
Debt Instrument [Line Items]
Debt Instrument, Periodic Payment, Principal	0
Fixed Rate Debt [Member] | 2021 [Member]
Debt Instrument [Line Items]
Debt Instrument, Periodic Payment, Principal	600,000	[1]
Floating Rate Debt [Member]
Debt Instrument [Line Items]
Long-term Debt, Percentage Bearing Variable Interest, Amount	425,000		269,000
Percentage of Total Debt	41.00%
Floating Rate Debt [Member] | 2015 [Member]
Debt Instrument [Line Items]
Debt Instrument, Periodic Payment, Principal	0
Floating Rate Debt [Member] | 2016 [Member]
Debt Instrument [Line Items]
Debt Instrument, Periodic Payment, Principal	3,750	[2]
Floating Rate Debt [Member] | 2017 [Member]
Debt Instrument [Line Items]
Debt Instrument, Periodic Payment, Principal	8,750	[2]
Floating Rate Debt [Member] | 2018 [Member]
Debt Instrument [Line Items]
Debt Instrument, Periodic Payment, Principal	162,500	[2],[3]
Floating Rate Debt [Member] | 2019 [Member]
Debt Instrument [Line Items]
Debt Instrument, Periodic Payment, Principal	250,000	[4]
Floating Rate Debt [Member] | 2020 [Member]
Debt Instrument [Line Items]
Debt Instrument, Periodic Payment, Principal	0
Floating Rate Debt [Member] | 2021 [Member]
Debt Instrument [Line Items]
Debt Instrument, Periodic Payment, Principal	0
After Fifth Amendment [Member] | Unsecured Credit Facility [Member]
Debt Instrument [Line Items]
Debt Instrument, Maturity Date	13-May-18
AccThreeTermLoan [Member]
Debt Instrument [Line Items]
Debt Instrument, Maturity Date	27-Mar-18
Debt Instrument, Frequency of Periodic Payment	Quarterly
AccThreeTermLoan [Member] | BeginningAprilOneTwoThousandSixteen [Member]
Debt Instrument [Line Items]
Debt Instrument, Periodic Payment, Principal	1,250
Debt Instrument, Date of First Required Payment	1-Apr-16
AccThreeTermLoan [Member] | BeginningAprilOneTwoThousandSeventeen [Member]
Debt Instrument [Line Items]
Debt Instrument, Periodic Payment, Principal	2,500
Debt Instrument, Date of Increased Required Payment	1-Apr-17
After First Amendment [Member] | Unsecured Term Loan [Member]
Debt Instrument [Line Items]
Debt Instrument, Maturity Date	21-Jul-19
[1]	The 5.875% Unsecured Notes due 2021 mature on September 15, 2021.
[2]	The ACC3 Term Loan matures on March 27, 2018 with no extension option. Quarterly principal payments of $1.25 million begin on April 1, 2016, increase to $2.5 million on April 1, 2017 and continue through maturity.
[3]	The Unsecured Credit Facility matures on May 13, 2018 with a one-year extension option.
[4]	The Unsecured Term Loan matures on July 21, 2019 with no extension option.

7_Related_Party_Transactions_D

7. Related Party Transactions (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Related Party Transaction [Line Items]
Related Party Transaction, Expenses from Transactions with Related Party	$0.10	$0.30	$0.20
Aircraft Charter In lieu of salary	0	0.1	0.5
Related Party Transaction Rental Expenses From Transactions With Related Party	0.4	0.4	0.4
Limited Liability Company (LLC) or Limited Partnership (LP), Members or Limited Partners, Ownership Interest	81.10%
Adjacent to Ashburn Corporate Center [Member]
Related Party Transaction [Line Items]
Purchase Of Undeveloped Parcel Of Land In Acres	34.8
Purchase Price of Undeveloped Land Parcel	15.5
Adjacent to Ashburn Corporate Center [Member] | Board of Directors Chairman [Member]
Related Party Transaction [Line Items]
Limited Liability Company (LLC) or Limited Partnership (LP), Members or Limited Partners, Ownership Interest	7.00%
Adjacent to Ashburn Corporate Center [Member] | Board of Directors Vice-Chairman [Member]
Related Party Transaction [Line Items]
Limited Liability Company (LLC) or Limited Partnership (LP), Members or Limited Partners, Ownership Interest	1.00%
Part of Ashburn Corporate Center [Member]
Related Party Transaction [Line Items]
Purchase Of Undeveloped Parcel Of Land In Acres	8.7
Purchase Price of Undeveloped Land Parcel	$4.60
Part of Ashburn Corporate Center [Member] | Board of Directors Chairman [Member]
Related Party Transaction [Line Items]
Limited Liability Company (LLC) or Limited Partnership (LP), Members or Limited Partners, Ownership Interest	23.00%
Part of Ashburn Corporate Center [Member] | Board of Directors Vice-Chairman [Member]
Related Party Transaction [Line Items]
Limited Liability Company (LLC) or Limited Partnership (LP), Members or Limited Partners, Ownership Interest	18.00%
Part of Ashburn Corporate Center [Member] | Director [Member]
Related Party Transaction [Line Items]
Limited Liability Company (LLC) or Limited Partnership (LP), Members or Limited Partners, Ownership Interest	4.00%

8_Commitments_and_Contingencie1

8. Commitments and Contingencies (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014
Long-term Purchase Commitment [Line Items]
Percentage Of Built In Gain That Can Be Recognized Without Triggering Tax Protection Provisions	80.00%
Initial Built In Gain	$667
Amount of Built In Gain That Can Be Recognized Without Triggering Tax Protection Provisions	534
Increase in Percentage of Built In Gain That Can Be Recognized Each Year Without Triggering Tax Protection Provisions	10.00%
Percentage Of Built In Gain That Can Be Recognized In Two Thousand Seventeen Without Triggering Tax Protection Provisions	100.00%
Built In Gain Amount Tax Protected	12
Built in Gain Amount Tax Protected, No Guarantee on Secured Loan	97
Percentage of Disinterested Members of Board for Approving Sales Resulting in Payments to Executives or Directors	75.00%
SC1 Phase IIB [Member]
Long-term Purchase Commitment [Line Items]
Estimated Control Cost	55.2
Amount of Control Estimate Incurred	43
Total Commitments For Purchase of Equipment And Labor Related to Development	3.6
CH2 [Member]
Long-term Purchase Commitment [Line Items]
Estimated Control Cost	168.9
Amount of Control Estimate Incurred	91.7
Total Commitments For Purchase of Equipment And Labor Related to Development	36.8
Adjacent to Ashburn Corporate Center [Member]
Long-term Purchase Commitment [Line Items]
Purchase Of Undeveloped Parcel Of Land In Acres	34.8
Purchase Price of Undeveloped Land Parcel	15.5
Part of Ashburn Corporate Center [Member]
Long-term Purchase Commitment [Line Items]
Purchase Of Undeveloped Parcel Of Land In Acres	8.7
Purchase Price of Undeveloped Land Parcel	$4.60

9_Redeemable_noncontrolling_in1

9. Redeemable noncontrolling interests operating partnership / Redeemable partnership units (Details) (USD $)	12 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Redeemable noncontrolling interests – operating partnership / Redeemable partnership units [Line Items]
Redeemable noncontrolling interests - operating partnership	$513,134	$387,244	$453,889	$461,739
Share Price	$33.24	$24.71
Redemption of operating partnership units, shares	234,300	3,115,269	277,575

10_Preferred_Stock_Preferred_S

10. Preferred Stock Preferred Stock Narrative (Details) (USD $)	12 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Series A cumulative redeemable perpetual preferred stock [Member]
Preferred Stock [Line Items]
Preferred stock, shares issued	7,400,000	7,400,000
Preferred Stock, Dividend Rate, Percentage	7.88%
Preferred stock, $.001 par value, 50,000,000 shares authorized	$185,000	$185,000
Preferred Stock, Liquidation Preference Per Share	$25
Preferred Stock, Redemption Price Per Share	$25
Preferred Stock, Increased Dividend Rate, Percentage	11.88%
Preferred Stock Redemption Period After Change in Control	90 days
Series B cumulative redeemable perpetual preferred stock [Member]
Preferred Stock [Line Items]
Preferred stock, shares issued	6,650,000	6,650,000
Preferred Stock, Dividend Rate, Percentage	7.63%
Preferred stock, $.001 par value, 50,000,000 shares authorized	$166,250	$166,250
Preferred Stock, Liquidation Preference Per Share	$25
Preferred Stock, Redemption Price Per Share	$25
Preferred Stock Redemption Period After Change in Control	120 days
Share Cap to Determine Redemption Price in Change in Control	2.105

10_Preferred_Stock_Preferred_S1

10. Preferred Stock Preferred Stock Schedule of Preferred Stock Dividend (Details) (USD $)	3 Months Ended												12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Series A Preferred Stock [Member]
Preferred Stock Dividend [Line Items]
Record Date	30-Dec-14	3-Oct-14	3-Jul-14	4-Apr-14	27-Dec-13	4-Oct-13	5-Jul-13	5-Apr-13	28-Dec-12	5-Oct-12	6-Jul-12	5-Apr-12
Payment Date	15-Jan-15	15-Oct-14	15-Jul-14	15-Apr-14	15-Jan-14	15-Oct-13	15-Jul-13	15-Apr-13	15-Jan-13	15-Oct-12	16-Jul-12	16-Apr-12
Cash Dividend	$0.49	$0.49	$0.49	$0.49	$0.49	$0.49	$0.49	$0.49	$0.49	$0.49	$0.49	$0.49	$1.97	$1.97	$1.97
Ordinary Taxable Dividend	$0.49	$0.49	$0.49	$0.49	$0.49	$0.49	$0.49	$0.49	$0.49	$0.49	$0.49	$0.49	$1.97	$1.97	$1.97
Nontaxable Return of Capital Distributions	$0	$0	$0	$0	$0	$0	$0	$0	$0	$0	$0	$0	$0	$0	$0
Series B Preferred Stock [Member]
Preferred Stock Dividend [Line Items]
Record Date	30-Dec-14	3-Oct-14	3-Jul-14	4-Apr-14	27-Dec-13	4-Oct-13	5-Jul-13	5-Apr-13	28-Dec-12	5-Oct-12	6-Jul-12	5-Apr-12
Payment Date	15-Jan-15	15-Oct-14	15-Jul-14	15-Apr-14	15-Jan-14	15-Oct-13	15-Jul-13	15-Apr-13	15-Jan-13	15-Oct-12	16-Jul-12	16-Apr-12
Cash Dividend	$0.48	$0.48	$0.48	$0.48	$0.48	$0.48	$0.48	$0.48	$0.48	$0.48	$0.48	$0.48	$1.91	$1.91	$1.91
Ordinary Taxable Dividend	$0.48	$0.48	$0.48	$0.48	$0.48	$0.48	$0.48	$0.48	$0.48	$0.48	$0.48	$0.48	$1.91	$1.91	$1.91
Nontaxable Return of Capital Distributions	$0	$0	$0	$0	$0	$0	$0	$0	$0	$0	$0	$0	$0	$0	$0

11_Stockholders_Equity_of_the_2

11. Stockholders Equity of the REIT and Partners Capital of the OP Stockholders Equity of the REIT and Partners Capital of the OP Narrative (Details) (USD $)	12 Months Ended			3 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012
Stockholders’ Equity of the REIT and Partners’ Capital of the OP [Line Items]
Issuance of stock awards, shares	163,187	216,209	157,025
Redemption of operating partnership units, shares	234,300	3,115,269	277,575
Stock Repurchase Program, Authorized Amount	$120,000,000	$122,200,000	$80,000,000	$120,000,000				$122,200,000				$80,000,000
Common stock repurchase, shares	0	-1,632,673
Common stock repurchases		$37,792,000
Common Stock [Member]
Stockholders’ Equity of the REIT and Partners’ Capital of the OP [Line Items]
Cash Dividend		$0.95	$0.62	$0.42	$0.35	$0.35	$0.35	$0.25	$0.25	$0.25	$0.20	$0.20	$0.15	$0.15	$0.12
Ordinary Taxable Dividend		$0.60	$0.57	$0.39	$0.35	$0.35	$0.35	$0	$0.21	$0.21	$0.17	$0.15	$0.15	$0.15	$0.12
January Two Zero One Five [Member] | Common Stock [Member]
Stockholders’ Equity of the REIT and Partners’ Capital of the OP [Line Items]
Ordinary Taxable Dividend	$0.03
January Two Zero One Four [Member] | Common Stock [Member]
Stockholders’ Equity of the REIT and Partners’ Capital of the OP [Line Items]
Ordinary Taxable Dividend	$0.25
January Two Zero One Three [Member] | Common Stock [Member]
Stockholders’ Equity of the REIT and Partners’ Capital of the OP [Line Items]
Ordinary Taxable Dividend	$0.05

11_Stockholders_Equity_of_the_3

11. Stockholders Equity of the REIT and Partners Capital of the OP Stockholders Equity of the REIT and Partners Capital of the OP Schedule of Common Stock Dividend (Details) (Common Stock [Member], USD $)	3 Months Ended												12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012
Common Stock [Member]
Class of Stock [Line Items]
Record Date	30-Dec-14	3-Oct-14	3-Jul-14	4-Apr-14	27-Dec-13	4-Oct-13	5-Jul-13	5-Apr-13	28-Dec-12	5-Oct-12	6-Jul-12	5-Apr-12
Payment Date	15-Jan-15	15-Oct-14	15-Jul-14	15-Apr-14	15-Jan-14	15-Oct-13	15-Jul-13	15-Apr-13	15-Jan-13	15-Oct-12	16-Jul-12	16-Apr-12
Cash Dividend	$0.42	$0.35	$0.35	$0.35	$0.25	$0.25	$0.25	$0.20	$0.20	$0.15	$0.15	$0.12	$0.95	$0.62
Ordinary Taxable Dividend	$0.39	$0.35	$0.35	$0.35	$0	$0.21	$0.21	$0.17	$0.15	$0.15	$0.15	$0.12	$0.60	$0.57
Nontaxable Return of Capital Distributions	$0	$0	$0	$0	$0	$0.04	$0.04	$0.03	$0	$0	$0	$0	$0.10	$0

12_Equity_Compensation_Plan_Na

12. Equity Compensation Plan Narrative (Details) (USD $)	12 Months Ended
In Millions, except Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Equity Compensation Plan [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercised, Intrinsic Value	$7.70	$4.50	$1.90
Maximum Number of Share Equivalents Authorized	6,300,000
Share equivalent ratio, other than stock options and SARs	2.36
Cumulative Share Equivalents Issued From The Plan	2,203,970
Share Equivalents Remaining Available	4,096,030
Shares of restricted stock, Granted	149,608	203,241	143,191
Value of Restricted Stock Awarded during period	3.8	4.6	3.2
Shares of restricted stock, Vested	125,798	162,353	314,571
Value of Restricted Stock on Vesting Date	3.4	3.8	7.2
Unearned Compensation on Restricted Stock	5
Performance units, forfeited	3,785	34,843	20,030
Weighted Average Fair Value, performance units forfeited	$23.98	$22.86	$22.38
Restricted Stock [Member]
Equity Compensation Plan [Line Items]
Weighted Average Vesting Period	1 year 0 months 37 days
Stock Options [Member]
Equity Compensation Plan [Line Items]
Weighted Average Vesting Period	0 years 0 months 183 days	0 years 0 months 292 days	0 years 0 months 292 days
Performance Shares [Member]
Equity Compensation Plan [Line Items]
Unearned Compensation on Restricted Stock	$3.20
Performance units, forfeited	0	22,091
Weighted Average Fair Value, performance units forfeited		$26.93
Minimum [Member]
Equity Compensation Plan [Line Items]
Potential Number Of Shares Issued At Vesting Of Performance Units	0.00%
Maximum [Member]
Equity Compensation Plan [Line Items]
Potential Number Of Shares Issued At Vesting Of Performance Units	300.00%

12_Equity_Compensation_Plan_Su

12. Equity Compensation Plan Summary of Restricted Stock (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Equity Compensation Plan [Line Items]
Shares of restricted stock, Unvested balance at beginning balance	303,964	297,919	489,329
Shares of restricted stock, Granted	149,608	203,241	143,191
Shares of restricted stock, Vested	-125,798	-162,353	-314,571
Shares of restricted stock, Forfeited	-3,785	-34,843	-20,030
Shares of restricted stock, Unvested balance at ending balance	323,989	303,964	297,919
Weighted Average Grant Date Fair Value, Unvested balance at beginning balance	$22.89	$22.31	$15.31
Weighted Average Grant Date Fair Value, Granted	$25.63	$22.82	$22.66
Weighted Average Grant Date Fair Value, Vested	$23.02	$21.73	$11.60
Weighted Average Grant Date Fair Value, Forfeited	$23.98	$22.86	$22.38
Weighted Average Grant Date Fair Value, Unvested balance at ending balance	$24.10	$22.89	$22.31

12_Equity_Compensation_Plan_Su1

12. Equity Compensation Plan Summary of Stock Options (Details) (USD $)	12 Months Ended
In Millions, except Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Equity Compensation Plan [Line Items]
Under option, beginning balance	2,099,910	2,076,781	1,902,843
Granted	0	374,214	341,541
Exercised	-507,056	-250,472	-113,955
Forfeited	0	-100,613	-53,648
Under option, ending balance	1,592,854	2,099,910	2,076,781
Weighted Average Exercise Price, Under Option, Beginning balance	$17.13	$15.17	$13.60
Weighted Average Exercise Price, Granted	$0	$22.62	$22.57
Weighted Average Exercise Price, Exercised	$10.95	$6.83	$7.62
Weighted Average Exercise Price, Forfeited	$0	$22.83	$22.60
Weighted Average Exercise Price, Under Option, Ending balance	$19.09	$17.13	$15.17
Total Unearned Compensation	$0.70	$1.90	$3.20
Weighted Average Remaining Contractual Term	6 years 0 months 73 days	6 years 0 months 329 days	7 years 0 months 110 days
Stock Options [Member]
Equity Compensation Plan [Line Items]
Weighted Average Vesting Period	0 years 0 months 183 days	0 years 0 months 292 days	0 years 0 months 292 days

12_Equity_Compensation_Plan_Su2

12. Equity Compensation Plan Summary of Unvested Stock Options (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Equity Compensation Plan [Line Items]
Unvested balance, beginning balance	684,111	809,991	1,256,478
Granted	0	374,214	341,541
Vested	-381,787	-399,481	-734,380
Forfeited	0	-100,613	-53,648
Unvested balance, ending balance	302,324	684,111	809,991
Weighted Average Grant Date Fair Value, Unvested at beginning balance	$5.73	$6.96	$5.63
Weighted Average Grant Date Fair Value, Granted	$0	$4.75	$5.79
Weighted Average Grant Date Fair Value, Vested	$6.28	$7.34	$4.18
Weighted Average Grant Date Fair Value, Forfeited	$0	$5.55
Weighted Average Grant Date Fair Value, Unvested at ending balance	$5.05	$5.73	$6.96

12_Equity_Compensation_Plan_Su3

12. Equity Compensation Plan Summary of Exercisable Stock Options (Details) (USD $)	12 Months Ended
In Millions, except Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Equity Compensation Plan [Line Items]
Options Exercisable, beginning balance	1,415,799	1,266,790	646,365
Vested	381,787	399,481	734,380
Exercised	-507,056	-250,472	-113,955
Options Exercisable, ending balance	1,290,530	1,415,799	1,266,790
Weighted Average Grant Date Fair Value, Exercisable at beginning balance	$4.81	$3.52	$2.61
Weighted Average Grant Date Fair Value, Vested	$6.28	$7.34	$4.18
Weighted Average Grant Date Fair Value, Exercised	$3.54	$2.35	$2.56
Weighted Average Grant Date Fair Value, Exercisable at ending balance	$5.74	$4.81	$3.52
Intrinsic Value	$19.30	$14.70	$17.60
Weighted Average Exercise Price	$18.27	$14.33	$10.24
Weighted Average Remaining Contractual Term	5 years 0 months 292 days	6 years 0 months 37 days	6 years 0 months 219 days

12_Equity_Compensation_Plan_Su4

12. Equity Compensation Plan Summary of Assumptions for Stock Options Granted (Details) (USD $)	12 Months Ended
In Millions, except Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Equity Compensation Plan [Line Items]
Number of Options Granted	0	374,214	341,541
Exercise Price	$0	$22.62	$22.57
Expected term (years)		5 years 0 months 0 days	4 years 0 months 0 days
Expected volatility		34.00%	39.00%
Expected annual dividend		4.00%	2.00%
Risk-free rate		0.83%	0.64%
Total grant fair value at date of grant (millions)		$1.80	$2

12_Equity_Compensation_Plan_Su5

12. Equity Compensation Plan Summary of Assumptions Used for Performance Units Granted (Details) (USD $)	12 Months Ended
In Millions, except Share data, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Equity Compensation Plan [Line Items]
Expected volatility		34.00%	39.00%
Expected annual dividend		4.00%	2.00%
Risk-free rate		0.83%	0.64%
Total grant fair value at date of grant (millions)		$1.80	$2
Performance Shares [Member]
Equity Compensation Plan [Line Items]
Performance Units Granted In Period	110,441	60,468	61,033
Expected volatility	30.00%	33.00%	29.00%
Expected annual dividend	5.00%	4.00%	2.00%
Risk-free rate	0.74%	0.40%	0.43%
Performance unit fair value at date of grant	$33.50	$25.59	$28.26
Total grant fair value at date of grant (millions)	3.7	1.5	1.7
Maximum value of grant on vesting date based on closing price of the Company's stock at the date of grant	$8.50	$4.10	$4.10

13_Earnings_Per_Share_of_the_R2

13. Earnings Per Share of the REIT (Details) (USD $)	3 Months Ended																12 Months Ended
In Thousands, except Share data, unless otherwise specified	Dec. 31, 2014		Sep. 30, 2014		Jun. 30, 2014		Mar. 31, 2014		Dec. 31, 2013		Sep. 30, 2013		Jun. 30, 2013		Mar. 31, 2013		Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Earnings per share of the REIT [Line Items]
Weighted average common shares – basic																	65,486,108	64,645,316	62,866,189
Effect of dilutive securities																	600,271	828,723	887,817
Weighted average common shares – diluted																	66,086,379	65,474,039	63,754,006
Net income attributable to common shares	$18,536		$18,960		$21,121		$20,045		$11,460		($10,228)		$11,971		$7,943		$78,662	$21,146	$25,977
Net income allocated to unvested restricted shares																	-484	-267	-188
Net income attributable to common shares, adjusted																	78,178	20,879	25,789
Earnings per common share – basic	$0.28		$0.29		$0.32		$0.30		$0.18	[1]	($0.16)	[1]	$0.19	[1]	$0.12	[1]	$1.19	$0.32	$0.41
Net income attributable to common shares																	78,178	21,146	25,977
Adjustments to redeemable noncontrolling interests																	0	55	84
Adjusted net income available to common shares																	$78,178	$21,201	$26,061
Earnings per common share – diluted	$0.28	[1]	$0.29	[1]	$0.32	[1]	$0.30	[1]	$0.18		($0.16)		$0.18		$0.12		$1.18	$0.32	$0.41
Restricted Shares																	0	0	0
Stock Options																	0	600,000	900,000
Performance Units																	100,000	100,000	100,000
[1]	Amounts do not equal full year results due to rounding in the second quarter of 2014.

14_Earnings_Per_Unit_of_the_Op2

14. Earnings Per Unit of the Operating Partnership (Details)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Earnings per unit of the Operating Partnership [Line Items]
Weighted average common units – basic (includes redeemable partnership units and units of general and limited partners)	81,053,127	80,580,556	81,750,958
Effect of dilutive securities	600,271	828,723	887,817
Weighted average common units – diluted	81,653,398	81,409,279	82,638,775
Restricted Units	0	0	0
Stock Options	0	600,000	900,000
Performance Units	100,000	100,000	100,000

15_Employee_Benefit_Plan_Detai

15. Employee Benefit Plan (Details) (USD $)	12 Months Ended
In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Employee Benefit Plan [Abstract]
Defined Benefit Plan, Contributions by Employer	$0.40	$0.40	$0.40
Percentage Of Employees Contribution Contributed By Employer	50.00%
Percentage Of Employee's Salary Contributed By Employer	4.00%

16_Fair_Value_Details

16. Fair Value (Details) (USD $)	Dec. 31, 2014	Dec. 31, 2013
Fair Value Disclosures [Abstract]
Long-term Debt	$1,025,000,000	$869,000,000
Long-term Debt, Fair Value	$1,037,800,000	$872,200,000
Derivative, Forward Interest Rate		1.68%

17_Quarterly_Financial_Informa2

17. Quarterly Financial Information (Details) (USD $)	3 Months Ended																12 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2014		Sep. 30, 2014		Jun. 30, 2014		Mar. 31, 2014		Dec. 31, 2013		Sep. 30, 2013		Jun. 30, 2013		Mar. 31, 2013		Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Quarterly Financial Information Disclosure [Abstract]
Total revenues	$107,977		$105,578		$101,950		$102,087		$99,444		$96,342		$91,564		$87,759		$417,592	$375,109	$332,445
Net income	29,737		30,272		32,958		31,644		21,089		-5,958		21,747		16,727		124,611	53,605	60,833
Net income attributable to common shares	$18,536		$18,960		$21,121		$20,045		$11,460		($10,228)		$11,971		$7,943		$78,662	$21,146	$25,977
Net income attributable to common shares	$0.28		$0.29		$0.32		$0.30		$0.18	[1]	($0.16)	[1]	$0.19	[1]	$0.12	[1]	$1.19	$0.32	$0.41
Net income attributable to common shares	$0.28	[1]	$0.29	[1]	$0.32	[1]	$0.30	[1]	$0.18		($0.16)		$0.18		$0.12		$1.18	$0.32	$0.41
[1]	Amounts do not equal full year results due to rounding in the second quarter of 2014.

18_Supplemental_Consolidating_2

18. Supplemental Consolidating Financial Data for Subsidiary Guarantors of the Unsecured Notes Supplemental Consolidating Balance Sheets (Details) (USD $)	Dec. 31, 2014		Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
In Thousands, unless otherwise specified
Supplemental Consolidating Statements Of Balance Sheets [Line Items]
Land	$83,793		$75,956
Buildings and improvements	2,623,539		2,420,986
Income producing property	2,707,332		2,496,942
Less: accumulated depreciation	-504,869		-413,394	-325,740	-242,245
Net income producing property	2,202,463		2,083,548
Construction in progress and land held for development	358,965	[1]	302,068
Net real estate	2,561,428		2,385,616
Cash and cash equivalents	29,598		38,733	23,578	14,402
Rents and other receivables	8,113		12,674
Deferred rent, net	142,365		150,038
Lease contracts above market value, net	8,054		9,154
Deferred costs, net	38,495		39,866
Prepaid expenses and other assets	48,295		44,507
Total assets	2,836,348		2,680,588
Mortgage notes payable	115,000		115,000
Unsecured Term Loan	250,000		154,000
Unsecured notes payable	600,000		600,000
Accounts payable and accrued liabilities	26,973		23,566
Construction costs payable	32,949		45,444
Accrued interest payable	10,759		9,983
Distribution payable	39,981		25,971
Lease contracts below market value, net	7,037		10,530
Prepaid rents and other liabilities	65,174		56,576
Total liabilities	1,207,873		1,041,070
Commitments and contingencies	0		0
Total liabilities and stockholders’ equity	2,836,348		2,680,588
Operating Partnership [Member]
Supplemental Consolidating Statements Of Balance Sheets [Line Items]
Income producing property			0
Net income producing property			0
Net real estate			0
Total assets			2,428,832
Total liabilities			793,533
Total partners’ capital			1,248,055
Total liabilities and stockholders’ equity			2,428,832
Subsidiary Guarantors [Member]
Supplemental Consolidating Statements Of Balance Sheets [Line Items]
Income producing property			2,393,299
Net income producing property			2,006,503
Net real estate			2,160,907
Total assets			2,372,721
Total liabilities			97,697
Total partners’ capital			2,275,024
Total liabilities and stockholders’ equity			2,372,721
Subsidiary Non-Guarantors [Member]
Supplemental Consolidating Statements Of Balance Sheets [Line Items]
Income producing property			103,643
Net income producing property			77,045
Net real estate			224,709
Total assets			246,937
Total liabilities			149,840
Total partners’ capital			97,097
Total liabilities and stockholders’ equity			246,937
Eliminations [Member]
Supplemental Consolidating Statements Of Balance Sheets [Line Items]
Income producing property			0
Net income producing property			0
Net real estate			0
Total assets			-2,372,121
Total liabilities			0
Total partners’ capital			-2,372,121
Total liabilities and stockholders’ equity			-2,372,121
DuPont Fabros Technology, L.P. [Member]
Supplemental Consolidating Statements Of Balance Sheets [Line Items]
Land	83,793		75,956
Buildings and improvements	2,623,539		2,420,986
Income producing property	2,707,332		2,496,942
Less: accumulated depreciation	-504,869		-413,394
Net income producing property	2,202,463		2,083,548
Construction in progress and land held for development	358,965		302,068
Net real estate	2,561,428		2,385,616
Cash and cash equivalents	25,380		34,514	19,282	10,097
Rents and other receivables	8,113		12,674
Deferred rent, net	142,365		150,038
Lease contracts above market value, net	8,054		9,154
Deferred costs, net	38,495		39,866
Investment in affiliates	0		0
Prepaid expenses and other assets	48,295		44,507
Total assets	2,832,130		2,676,369
Line of credit	60,000		0
Mortgage notes payable	115,000		115,000
Unsecured Term Loan	250,000		154,000
Unsecured notes payable	600,000		600,000
Accounts payable and accrued liabilities	26,973		23,566
Construction costs payable	32,949		45,444
Accrued interest payable	10,759		9,983
Distribution payable	39,981		25,971
Lease contracts below market value, net	7,037		10,530
Prepaid rents and other liabilities	65,174		56,576
Total liabilities	1,207,873		1,041,070
Redeemable partnership units	513,134		387,244
Commitments and contingencies	0		0
General Partners' Capital	7,619		9,110
Total partners’ capital	1,111,123		1,248,055	1,262,136	1,202,830
Total liabilities and stockholders’ equity	2,832,130		2,676,369
DuPont Fabros Technology, L.P. [Member] | Operating Partnership [Member]
Supplemental Consolidating Statements Of Balance Sheets [Line Items]
Land	0		0
Buildings and improvements	0		0
Income producing property	0
Less: accumulated depreciation	0		0
Net income producing property	0
Construction in progress and land held for development	0		0
Net real estate	0
Cash and cash equivalents	21,806		32,903	18,240	9,174
Rents and other receivables	1,775		4,226
Deferred rent, net	0		0
Lease contracts above market value, net	0		0
Deferred costs, net	15,957		17,318
Investment in affiliates	2,547,049		2,372,121
Prepaid expenses and other assets	2,865		2,264
Total assets	2,589,452
Line of credit	60,000		0
Mortgage notes payable	0		0
Unsecured Term Loan	250,000		154,000
Unsecured notes payable	600,000		600,000
Accounts payable and accrued liabilities	4,432		3,547
Construction costs payable	0		0
Accrued interest payable	10,754		9,970
Distribution payable	39,981		25,971
Lease contracts below market value, net	0		0
Prepaid rents and other liabilities	28		45
Total liabilities	965,195
Redeemable partnership units	513,134		387,244
Commitments and contingencies	0		0
General Partners' Capital	7,619		9,110
Total partners’ capital	1,111,123
Total liabilities and stockholders’ equity	2,589,452
DuPont Fabros Technology, L.P. [Member] | Subsidiary Guarantors [Member]
Supplemental Consolidating Statements Of Balance Sheets [Line Items]
Land	79,935		74,885
Buildings and improvements	2,427,706		2,318,414
Income producing property	2,507,641
Less: accumulated depreciation	-473,203		-386,796
Net income producing property	2,034,438
Construction in progress and land held for development	145,229		154,404
Net real estate	2,179,667
Cash and cash equivalents	0		0	361	196
Rents and other receivables	5,513		3,981
Deferred rent, net	139,542		144,377
Lease contracts above market value, net	8,054		9,154
Deferred costs, net	16,098		16,971
Investment in affiliates	0		0
Prepaid expenses and other assets	43,866		37,331
Total assets	2,392,740
Line of credit	0		0
Mortgage notes payable	0		0
Unsecured Term Loan	0		0
Unsecured notes payable	0		0
Accounts payable and accrued liabilities	19,580		14,582
Construction costs payable	4,312		22,670
Accrued interest payable	0		0
Distribution payable	0		0
Lease contracts below market value, net	7,037		10,530
Prepaid rents and other liabilities	61,728		49,915
Total liabilities	92,657
Redeemable partnership units	0		0
Commitments and contingencies	0		0
General Partners' Capital	0		0
Total partners’ capital	2,300,083
Total liabilities and stockholders’ equity	2,392,740
DuPont Fabros Technology, L.P. [Member] | Subsidiary Non-Guarantors [Member]
Supplemental Consolidating Statements Of Balance Sheets [Line Items]
Land	3,858		1,071
Buildings and improvements	195,833		102,572
Income producing property	199,691
Less: accumulated depreciation	-31,666		-26,598
Net income producing property	168,025
Construction in progress and land held for development	213,736		147,664
Net real estate	381,761
Cash and cash equivalents	3,574		1,611	681	727
Rents and other receivables	825		4,467
Deferred rent, net	2,823		5,661
Lease contracts above market value, net	0		0
Deferred costs, net	6,440		5,577
Investment in affiliates	0		0
Prepaid expenses and other assets	1,564		4,912
Total assets	396,987
Line of credit	0		0
Mortgage notes payable	115,000		115,000
Unsecured Term Loan	0		0
Unsecured notes payable	0		0
Accounts payable and accrued liabilities	2,961		5,437
Construction costs payable	28,637		22,774
Accrued interest payable	5		13
Distribution payable	0		0
Lease contracts below market value, net	0		0
Prepaid rents and other liabilities	3,418		6,616
Total liabilities	150,021
Redeemable partnership units	0		0
Commitments and contingencies	0		0
General Partners' Capital	0		0
Total partners’ capital	246,966
Total liabilities and stockholders’ equity	396,987
DuPont Fabros Technology, L.P. [Member] | Eliminations [Member]
Supplemental Consolidating Statements Of Balance Sheets [Line Items]
Land	0		0
Buildings and improvements	0		0
Income producing property	0
Less: accumulated depreciation	0		0
Net income producing property	0
Construction in progress and land held for development	0		0
Net real estate	0
Cash and cash equivalents	0		0	0	0
Rents and other receivables	0		0
Deferred rent, net	0		0
Lease contracts above market value, net	0		0
Deferred costs, net	0		0
Investment in affiliates	-2,547,049		-2,372,121
Prepaid expenses and other assets	0		0
Total assets	-2,547,049
Line of credit	0		0
Mortgage notes payable	0		0
Unsecured Term Loan	0		0
Unsecured notes payable	0		0
Accounts payable and accrued liabilities	0		0
Construction costs payable	0		0
Accrued interest payable	0		0
Distribution payable	0		0
Lease contracts below market value, net	0		0
Prepaid rents and other liabilities	0		0
Total liabilities	0
Redeemable partnership units	0		0
Commitments and contingencies	0		0
General Partners' Capital	0		0
Total partners’ capital	-2,547,049
Total liabilities and stockholders’ equity	-2,547,049
DuPont Fabros Technology, L.P. [Member] | Series A Preferred Stock [Member]
Supplemental Consolidating Statements Of Balance Sheets [Line Items]
Limited Partners' Capital	185,000		185,000
DuPont Fabros Technology, L.P. [Member] | Series A Preferred Stock [Member] | Operating Partnership [Member]
Supplemental Consolidating Statements Of Balance Sheets [Line Items]
Limited Partners' Capital	185,000		185,000
DuPont Fabros Technology, L.P. [Member] | Series A Preferred Stock [Member] | Subsidiary Guarantors [Member]
Supplemental Consolidating Statements Of Balance Sheets [Line Items]
Limited Partners' Capital	0		0
DuPont Fabros Technology, L.P. [Member] | Series A Preferred Stock [Member] | Subsidiary Non-Guarantors [Member]
Supplemental Consolidating Statements Of Balance Sheets [Line Items]
Limited Partners' Capital	0		0
DuPont Fabros Technology, L.P. [Member] | Series A Preferred Stock [Member] | Eliminations [Member]
Supplemental Consolidating Statements Of Balance Sheets [Line Items]
Limited Partners' Capital	0		0
DuPont Fabros Technology, L.P. [Member] | Series B Preferred Stock [Member]
Supplemental Consolidating Statements Of Balance Sheets [Line Items]
Limited Partners' Capital	166,250		166,250
DuPont Fabros Technology, L.P. [Member] | Series B Preferred Stock [Member] | Operating Partnership [Member]
Supplemental Consolidating Statements Of Balance Sheets [Line Items]
Limited Partners' Capital	166,250		166,250
DuPont Fabros Technology, L.P. [Member] | Series B Preferred Stock [Member] | Subsidiary Guarantors [Member]
Supplemental Consolidating Statements Of Balance Sheets [Line Items]
Limited Partners' Capital	0		0
DuPont Fabros Technology, L.P. [Member] | Series B Preferred Stock [Member] | Subsidiary Non-Guarantors [Member]
Supplemental Consolidating Statements Of Balance Sheets [Line Items]
Limited Partners' Capital	0		0
DuPont Fabros Technology, L.P. [Member] | Series B Preferred Stock [Member] | Eliminations [Member]
Supplemental Consolidating Statements Of Balance Sheets [Line Items]
Limited Partners' Capital	0		0
DuPont Fabros Technology, L.P. [Member] | Limited partners' common units [Member]
Supplemental Consolidating Statements Of Balance Sheets [Line Items]
Limited Partners' Capital	752,254		887,695
DuPont Fabros Technology, L.P. [Member] | Limited partners' common units [Member] | Operating Partnership [Member]
Supplemental Consolidating Statements Of Balance Sheets [Line Items]
Limited Partners' Capital	752,254		887,695
DuPont Fabros Technology, L.P. [Member] | Limited partners' common units [Member] | Subsidiary Guarantors [Member]
Supplemental Consolidating Statements Of Balance Sheets [Line Items]
Limited Partners' Capital	2,300,083		2,275,024
DuPont Fabros Technology, L.P. [Member] | Limited partners' common units [Member] | Subsidiary Non-Guarantors [Member]
Supplemental Consolidating Statements Of Balance Sheets [Line Items]
Limited Partners' Capital	246,966		97,097
DuPont Fabros Technology, L.P. [Member] | Limited partners' common units [Member] | Eliminations [Member]
Supplemental Consolidating Statements Of Balance Sheets [Line Items]
Limited Partners' Capital	($2,547,049)		($2,372,121)
[1]	(1)Properties located in Ashburn, VA (ACC7 Phases II-IV and ACC8); Piscataway, NJ (NJ1 Phase II), Elk Grove Village, IL (CH2) and Santa Clara, CA (SC1 Phase IIB and SC2).

18_Supplemental_Consolidating_3

18. Supplemental Consolidating Financial Data for Subsidiary Guarantors of the Unsecured Notes Supplemental Consolidating Statements of Operations (Details) (USD $)	3 Months Ended								12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Revenues:
Base rent									$285,716	$265,695	$236,810
Recoveries from tenants									124,853	104,271	91,049
Other revenues									7,023	5,143	4,586
Total revenues	107,977	105,578	101,950	102,087	99,444	96,342	91,564	87,759	417,592	375,109	332,445
Expenses:
Property operating costs									117,339	103,522	94,646
Real estate taxes and insurance									14,195	14,380	12,689
Depreciation and amortization									96,780	93,058	89,241
General and administrative									17,181	16,261	17,024
Other expenses									9,222	3,650	6,919
Total expenses									254,717	230,871	220,519
Operating income									162,875	144,238	111,926
Interest income									116	137	168
Interest:
Expense incurred									-33,699	-46,443	-47,765
Amortization of deferred financing costs									-2,980	-3,349	-3,496
Loss on early extinguishment of debt									-1,701	-40,978	0
Net income	29,737	30,272	32,958	31,644	21,089	-5,958	21,747	16,727	124,611	53,605	60,833
Preferred stock dividends									-27,245	-27,245	-27,053
DuPont Fabros Technology, L.P. [Member]
Revenues:
Base rent									285,716	265,695	236,810
Recoveries from tenants									124,853	104,271	91,049
Other revenues									7,023	5,143	4,586
Total revenues									417,592	375,109	332,445
Expenses:
Property operating costs									117,339	103,522	94,646
Real estate taxes and insurance									14,195	14,380	12,689
Depreciation and amortization									96,780	93,058	89,241
General and administrative									17,181	16,261	17,024
Other expenses									9,222	3,650	6,919
Total expenses									254,717	230,871	220,519
Operating income									162,875	144,238	111,926
Interest income									116	137	168
Interest:
Expense incurred									-33,699	-46,443	-47,765
Amortization of deferred financing costs									-2,980	-3,349	-3,496
Loss on early extinguishment of debt									-1,701	-40,978	0
Equity in earnings									0	0	0
Net income									124,611	53,605	60,833
Preferred stock dividends									-27,245	-27,245	-27,053
Net Income Loss Available To Common Unit holders Basic									97,366	26,360	33,780
DuPont Fabros Technology, L.P. [Member] | Operating Partnership [Member]
Revenues:
Base rent									17,499	15,301	13,765
Recoveries from tenants									0	0	0
Other revenues									0	0	0
Total revenues									17,499	15,301	13,765
Expenses:
Property operating costs									0	198	0
Real estate taxes and insurance									0	0	0
Depreciation and amortization									63	81	117
General and administrative									16,159	15,605	14,531
Other expenses									3,508	778	1,437
Total expenses									19,730	16,662	16,085
Operating income									-2,231	-1,361	-2,320
Interest income									115	-148	432
Interest:
Expense incurred									-41,222	-47,343	-47,535
Amortization of deferred financing costs									-3,173	-3,054	-2,748
Loss on early extinguishment of debt									-1,701	-39,278
Equity in earnings									172,823	144,789	113,004
Net income									124,611	53,605	60,833
Preferred stock dividends									-27,245	-27,245	-27,053
Net Income Loss Available To Common Unit holders Basic									97,366	26,360	33,780
DuPont Fabros Technology, L.P. [Member] | Subsidiary Guarantors [Member]
Revenues:
Base rent									267,454	248,719	218,208
Recoveries from tenants									115,185	94,794	80,387
Other revenues									1,657	1,668	1,378
Total revenues									384,296	345,181	299,973
Expenses:
Property operating costs									123,140	108,536	97,036
Real estate taxes and insurance									13,323	13,931	12,167
Depreciation and amortization									90,770	88,556	83,902
General and administrative									82	97	128
Other expenses									1,526	304	3,031
Total expenses									228,841	211,424	196,264
Operating income									155,455	133,757	103,709
Interest income									0	20	0
Interest:
Expense incurred									4,323	351	-420
Amortization of deferred financing costs									273	-167	-760
Loss on early extinguishment of debt									0	-1,700
Equity in earnings									0	0	0
Net income									160,051	132,261	102,529
Preferred stock dividends									0	0	0
Net Income Loss Available To Common Unit holders Basic									160,051	132,261	102,529
DuPont Fabros Technology, L.P. [Member] | Subsidiary Non-Guarantors [Member]
Revenues:
Base rent									18,413	17,126	18,752
Recoveries from tenants									9,668	9,477	10,662
Other revenues									5,489	3,613	3,335
Total revenues									33,570	30,216	32,749
Expenses:
Property operating costs									11,822	10,227	11,502
Real estate taxes and insurance									872	449	522
Depreciation and amortization									5,947	4,421	5,222
General and administrative									940	559	2,365
Other expenses									4,338	2,718	2,601
Total expenses									23,919	18,374	22,212
Operating income									9,651	11,842	10,537
Interest income									1	0	0
Interest:
Expense incurred									3,200	814	-74
Amortization of deferred financing costs									-80	-128	12
Loss on early extinguishment of debt									0	0
Equity in earnings									0	0	0
Net income									12,772	12,528	10,475
Preferred stock dividends									0	0	0
Net Income Loss Available To Common Unit holders Basic									12,772	12,528	10,475
DuPont Fabros Technology, L.P. [Member] | Eliminations [Member]
Revenues:
Base rent									-17,650	-15,451	-13,915
Recoveries from tenants									0	0	0
Other revenues									-123	-138	-127
Total revenues									-17,773	-15,589	-14,042
Expenses:
Property operating costs									-17,623	-15,439	-13,892
Real estate taxes and insurance									0	0	0
Depreciation and amortization									0	0	0
General and administrative									0	0	0
Other expenses									-150	-150	-150
Total expenses									-17,773	-15,589	-14,042
Operating income									0	0	0
Interest income									0	265	-264
Interest:
Expense incurred									0	-265	264
Amortization of deferred financing costs									0	0	0
Loss on early extinguishment of debt									0	0
Equity in earnings									-172,823	-144,789	-113,004
Net income									-172,823	-144,789	-113,004
Preferred stock dividends									0	0	0
Net Income Loss Available To Common Unit holders Basic									($172,823)	($144,789)	($113,004)

18_Supplemental_Consolidating_4

18. Supplemental Consolidating Financial Data for Subsidiary Guarantors of the Unsecured Notes Supplemental Consodlidating Statements of Cash Flows (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Supplemental Consolidating Statements Of Cash Flows [Line Items]
Net Cash Provided by (Used in) Operating Activities	$244,513	$193,761	$132,763
Investments in real estate – development	-265,374	-129,332	-94,753
Payments to Acquire Land	0	-14,186	-3,830
Interest capitalized for real estate under development	-9,644	-3,774	-4,434
Improvements to real estate	-1,916	-5,757	-4,426
Additions to non-real estate property	-316	-71	-57
Net cash used in investing activities	-277,250	-153,120	-107,500
Proceeds from line of credit	60,000	102,000	48,000
Repayments	0	-120,000	-50,000
Proceeds	0	115,000	0
Lump sum payoffs	0	-138,300	0
Repayments of Secured Debt	0	-1,300	-5,200
Proceeds	96,000	154,000	0
Proceeds	0	600,000	0
Repayments	0	-550,000	0
Payments of financing costs	-3,829	-18,200	-2,109
Payments for early extinguishment of debt	0	-32,544	0
Issuance of OP units for stock options exercises, net	4,363	1,711	868
Common stock repurchases	0	-37,792	0
Net Cash Provided by (Used in) Financing Activities	23,602	-25,486	-16,087
Cash and Cash Equivalents, Period Increase (Decrease)	-9,135	15,155	9,176
Cash and cash equivalents, ending	29,598	38,733	23,578
DuPont Fabros Technology, L.P. [Member]
Supplemental Consolidating Statements Of Cash Flows [Line Items]
Net Cash Provided by (Used in) Operating Activities	244,514	193,761	132,763
Investments in real estate – development	-265,374	-129,332	-94,753
Payments to Acquire Land	0	-14,186	-3,830
Investments in affiliates	0	0	0
Interest capitalized for real estate under development	-9,644	-3,774	-4,434
Improvements to real estate	-1,916	-5,757	-4,426
Additions to non-real estate property	-316	-71	-57
Net cash used in investing activities	-277,250	-153,120	-107,500
Proceeds from line of credit	60,000	102,000	48,000
Repayments	0	-120,000	-50,000
Proceeds	0	115,000	0
Lump sum payoffs	0	-138,300	0
Repayments of Secured Debt	0	-1,300	-5,200
Proceeds	96,000	154,000	0
Proceeds	0	600,000	0
Repayments	0	-550,000	0
Payments of financing costs	-3,829	-18,123	-2,109
Payments for early extinguishment of debt	0	-32,544	0
Issuance of OP units for stock options exercises, net	4,363	1,711	868
Proceeds from Issuance of Preferred Limited Partners Units			-62,694
Common stock repurchases	0	-37,792	0
Payments of Distributions to Affiliates	-132,932	-100,061	-70,331
Net Cash Provided by (Used in) Financing Activities	23,602	-25,409	-16,078
Cash and Cash Equivalents, Period Increase (Decrease)	-9,134	15,232	9,185
Cash and cash equivalents, ending	25,380	34,514	19,282
DuPont Fabros Technology, L.P. [Member] | Operating Partnership [Member]
Supplemental Consolidating Statements Of Cash Flows [Line Items]
Net Cash Provided by (Used in) Operating Activities	-40,234	-48,725	-49,869
Investments in real estate – development	-404	-9	-26
Payments to Acquire Land	0	0	0
Investments in affiliates	5,654	62,508	69,833
Interest capitalized for real estate under development	-10	0	0
Improvements to real estate	0	0	0
Additions to non-real estate property	-20	-6	-19
Net cash used in investing activities	5,220	62,493	69,788
Proceeds from line of credit	60,000	102,000	48,000
Repayments		-120,000	-50,000
Proceeds		0
Lump sum payoffs		0
Repayments of Secured Debt		0	0
Proceeds	96,000	154,000
Proceeds		600,000
Repayments		-550,000
Payments of financing costs	-3,514	-16,419	-2,084
Payments for early extinguishment of debt		-32,544
Issuance of OP units for stock options exercises, net	4,363	1,711	868
Proceeds from Issuance of Preferred Limited Partners Units			-62,694
Common stock repurchases		-37,792
Payments of Distributions to Affiliates	-132,932	-100,061	-70,331
Net Cash Provided by (Used in) Financing Activities	23,917	895	-10,853
Cash and Cash Equivalents, Period Increase (Decrease)	-11,097	14,663	9,066
Cash and cash equivalents, ending	21,806	32,903	18,240
DuPont Fabros Technology, L.P. [Member] | Subsidiary Guarantors [Member]
Supplemental Consolidating Statements Of Cash Flows [Line Items]
Net Cash Provided by (Used in) Operating Activities	264,409	225,903	168,236
Investments in real estate – development	-111,791	-50,827	-84,877
Payments to Acquire Land	0	0	-3,830
Investments in affiliates	-146,188	-28,856	-65,480
Interest capitalized for real estate under development	-4,323	-1,399	-4,244
Improvements to real estate	-1,850	-5,513	-4,395
Additions to non-real estate property	-257	-65	-20
Net cash used in investing activities	-264,409	-86,660	-162,846
Proceeds from line of credit	0	0	0
Repayments		0	0
Proceeds		0
Lump sum payoffs		-138,300
Repayments of Secured Debt		-1,300	-5,200
Proceeds	0	0
Proceeds		0
Repayments		0
Payments of financing costs	0	-4	-25
Payments for early extinguishment of debt		0
Issuance of OP units for stock options exercises, net	0	0	0
Proceeds from Issuance of Preferred Limited Partners Units			0
Common stock repurchases		0
Payments of Distributions to Affiliates	0	0	0
Net Cash Provided by (Used in) Financing Activities	0	-139,604	-5,225
Cash and Cash Equivalents, Period Increase (Decrease)	0	-361	165
Cash and cash equivalents, ending	0	0	361
DuPont Fabros Technology, L.P. [Member] | Subsidiary Non-Guarantors [Member]
Supplemental Consolidating Statements Of Cash Flows [Line Items]
Net Cash Provided by (Used in) Operating Activities	20,339	16,583	14,396
Investments in real estate – development	-153,179	-78,496	-9,850
Payments to Acquire Land	0	-14,186	0
Investments in affiliates	140,534	-33,652	-4,353
Interest capitalized for real estate under development	-5,311	-2,375	-190
Improvements to real estate	-66	-244	-31
Additions to non-real estate property	-39	0	-18
Net cash used in investing activities	-18,061	-128,953	-14,442
Proceeds from line of credit	0	0	0
Repayments		0	0
Proceeds		115,000
Lump sum payoffs		0
Repayments of Secured Debt		0	0
Proceeds	0	0
Proceeds		0
Repayments		0
Payments of financing costs	-315	-1,700	0
Payments for early extinguishment of debt		0
Issuance of OP units for stock options exercises, net	0	0	0
Proceeds from Issuance of Preferred Limited Partners Units			0
Common stock repurchases		0
Payments of Distributions to Affiliates	0	0	0
Net Cash Provided by (Used in) Financing Activities	-315	113,300	0
Cash and Cash Equivalents, Period Increase (Decrease)	1,963	930	-46
Cash and cash equivalents, ending	3,574	1,611	681
DuPont Fabros Technology, L.P. [Member] | Eliminations [Member]
Supplemental Consolidating Statements Of Cash Flows [Line Items]
Net Cash Provided by (Used in) Operating Activities	0	0	0
Investments in real estate – development	0	0	0
Payments to Acquire Land	0	0	0
Investments in affiliates	0	0	0
Interest capitalized for real estate under development	0	0	0
Improvements to real estate	0	0	0
Additions to non-real estate property	0	0	0
Net cash used in investing activities	0	0	0
Proceeds from line of credit	0	0	0
Repayments		0	0
Proceeds		0
Lump sum payoffs		0
Repayments of Secured Debt		0	0
Proceeds	0	0
Proceeds		0
Repayments		0
Payments of financing costs	0	0	0
Payments for early extinguishment of debt		0
Issuance of OP units for stock options exercises, net	0	0	0
Proceeds from Issuance of Preferred Limited Partners Units			0
Common stock repurchases		0
Payments of Distributions to Affiliates	0	0	0
Net Cash Provided by (Used in) Financing Activities	0	0	0
Cash and Cash Equivalents, Period Increase (Decrease)	0	0	0
Cash and cash equivalents, ending	$0	$0	$0

Schedule_II_Consolidated_Allow2

Schedule II - Consolidated Allowance for Doubtful Accounts (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Valuation and Qualifying Accounts Disclosure [Line Items]
Allowance for doubtful accounts, Balance at Beginning of Period	$3,700	$2,961	$0
Charges to operations	4,829	739	2,961
Net recovery (Deductions)	-9	0	0
Allowance for doubtful accounts, Balance at End of Period	$8,520	$3,700	$2,961

Schedule_III_Consolidated_Real2

Schedule III - Consolidated Real Estate and Accumulated Depreciation Real Estate and Accumulated Depreciation (Details) (USD $)	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Real Estate and Accumulated Depreciation [Line Items]
Real Estate, Federal Income Tax Basis	$2,360,000,000
Real Estate and Accumulated Depreciation, Amount of Encumbrances	115,000,000
Real Estate and Accumulated Depreciation, Initial Cost of Land	122,520,000
Real Estate and Accumulated Depreciation, Initial Cost of Buildings and Improvements	1,940,446,000
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Carrying Costs	1,161,000
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Improvements	1,002,170,000
Real Estate and Accumulated Depreciation, Carrying Amount of Land	123,681,000
Real Estate and Accumulated Depreciation, Carrying Amount of Buildings and Improvements	2,942,616,000
Real Estate and Accumulated Depreciation, Carrying Amount of Land and Buildings and Improvements	3,066,297,000		2,799,010,000	2,607,630,000	2,507,381,000
Real Estate and Accumulated Depreciation, Accumulated Depreciation	504,869,000		413,394,000	325,740,000	242,245,000
ACC2 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Amount of Encumbrances	0	[1]
Real Estate and Accumulated Depreciation, Initial Cost of Land	2,500,000	[1]
Real Estate and Accumulated Depreciation, Initial Cost of Buildings and Improvements	157,100,000	[1]
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Carrying Costs	0	[1]
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Improvements	2,058,000	[1]
Real Estate and Accumulated Depreciation, Carrying Amount of Land	2,500,000	[1]
Real Estate and Accumulated Depreciation, Carrying Amount of Buildings and Improvements	159,158,000	[1]
Real Estate and Accumulated Depreciation, Carrying Amount of Land and Buildings and Improvements	161,658,000	[1]
Real Estate and Accumulated Depreciation, Accumulated Depreciation	50,035,000	[1]
Real Estate and Accumulated Depreciation, Year of Construction	2005
Real Estate And Accumulated Depreciation, Year Acquired	2001
ACC3 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Amount of Encumbrances	115,000,000	[2]
Real Estate and Accumulated Depreciation, Initial Cost of Land	1,071,000	[2]
Real Estate and Accumulated Depreciation, Initial Cost of Buildings and Improvements	0	[2]
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Carrying Costs	0	[2]
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Improvements	95,926,000	[2]
Real Estate and Accumulated Depreciation, Carrying Amount of Land	1,071,000	[2]
Real Estate and Accumulated Depreciation, Carrying Amount of Buildings and Improvements	95,926,000	[2]
Real Estate and Accumulated Depreciation, Carrying Amount of Land and Buildings and Improvements	96,997,000	[2]
Real Estate and Accumulated Depreciation, Accumulated Depreciation	29,313,000	[2]
Real Estate and Accumulated Depreciation, Year of Construction	2006
Real Estate And Accumulated Depreciation, Year Acquired	2001
ACC4 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Amount of Encumbrances	0	[1]
Real Estate and Accumulated Depreciation, Initial Cost of Land	6,600,000	[1]
Real Estate and Accumulated Depreciation, Initial Cost of Buildings and Improvements	506,081,000	[1]
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Carrying Costs	0	[1]
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Improvements	32,470,000	[1]
Real Estate and Accumulated Depreciation, Carrying Amount of Land	6,600,000	[1]
Real Estate and Accumulated Depreciation, Carrying Amount of Buildings and Improvements	538,551,000	[1]
Real Estate and Accumulated Depreciation, Carrying Amount of Land and Buildings and Improvements	545,151,000	[1]
Real Estate and Accumulated Depreciation, Accumulated Depreciation	137,876,000	[1]
Real Estate and Accumulated Depreciation, Year of Construction	2007
Real Estate And Accumulated Depreciation, Year Acquired	2006
ACC5 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Amount of Encumbrances	0	[1]
Real Estate and Accumulated Depreciation, Initial Cost of Land	6,443,000	[1]
Real Estate and Accumulated Depreciation, Initial Cost of Buildings and Improvements	43,000	[1]
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Carrying Costs	0	[1]
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Improvements	298,478,000	[1]
Real Estate and Accumulated Depreciation, Carrying Amount of Land	6,443,000	[1]
Real Estate and Accumulated Depreciation, Carrying Amount of Buildings and Improvements	298,521,000	[1]
Real Estate and Accumulated Depreciation, Carrying Amount of Land and Buildings and Improvements	304,964,000	[1]
Real Estate and Accumulated Depreciation, Accumulated Depreciation	50,191,000	[1]
Real Estate And Accumulated Depreciation, Year Acquired	2007
ACC6 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Amount of Encumbrances	0	[1]
Real Estate and Accumulated Depreciation, Initial Cost of Land	5,518,000	[1]
Real Estate and Accumulated Depreciation, Initial Cost of Buildings and Improvements	214,294,000	[1]
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Carrying Costs	0	[1]
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Improvements	2,403,000	[1]
Real Estate and Accumulated Depreciation, Carrying Amount of Land	5,518,000	[1]
Real Estate and Accumulated Depreciation, Carrying Amount of Buildings and Improvements	216,697,000	[1]
Real Estate and Accumulated Depreciation, Carrying Amount of Land and Buildings and Improvements	222,215,000	[1]
Real Estate and Accumulated Depreciation, Accumulated Depreciation	20,207,000	[1]
Real Estate And Accumulated Depreciation, Year Acquired	2007
ACC7 Phase I [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Amount of Encumbrances	0	[1]
Real Estate and Accumulated Depreciation, Initial Cost of Land	2,787,000	[1]
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Carrying Costs	0	[1]
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Improvements	92,989,000	[1]
Real Estate and Accumulated Depreciation, Carrying Amount of Land	2,787,000	[1]
Real Estate and Accumulated Depreciation, Carrying Amount of Buildings and Improvements	92,989,000	[1]
Real Estate and Accumulated Depreciation, Carrying Amount of Land and Buildings and Improvements	95,776,000	[1]
Real Estate and Accumulated Depreciation, Accumulated Depreciation	1,315,000	[1]
Real Estate and Accumulated Depreciation, Year of Construction	2014
Real Estate And Accumulated Depreciation, Year Acquired	2011
CH1 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Amount of Encumbrances	0	[1]
Real Estate and Accumulated Depreciation, Initial Cost of Land	22,450,000	[1]
Real Estate and Accumulated Depreciation, Initial Cost of Buildings and Improvements	238,746,000	[1]
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Carrying Costs	1,161,000	[1]
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Improvements	119,666,000	[1]
Real Estate and Accumulated Depreciation, Carrying Amount of Land	23,611,000	[1]
Real Estate and Accumulated Depreciation, Carrying Amount of Buildings and Improvements	358,412,000	[1]
Real Estate and Accumulated Depreciation, Carrying Amount of Land and Buildings and Improvements	382,023,000	[1]
Real Estate and Accumulated Depreciation, Accumulated Depreciation	57,891,000	[1]
Real Estate And Accumulated Depreciation, Year Acquired	2007
NJ1 Phase I [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Amount of Encumbrances	0	[1]
Real Estate and Accumulated Depreciation, Initial Cost of Land	4,311,000	[1]
Real Estate and Accumulated Depreciation, Initial Cost of Buildings and Improvements	191,649,000	[1]
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Carrying Costs	0	[1]
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Improvements	18,487,000	[1]
Real Estate and Accumulated Depreciation, Carrying Amount of Land	4,311,000	[1]
Real Estate and Accumulated Depreciation, Carrying Amount of Buildings and Improvements	210,136,000	[1]
Real Estate and Accumulated Depreciation, Carrying Amount of Land and Buildings and Improvements	214,447,000	[1]
Real Estate and Accumulated Depreciation, Accumulated Depreciation	29,064,000	[1]
Real Estate And Accumulated Depreciation, Year Acquired	2007
SC1 Phase I and IIA [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Amount of Encumbrances	0	[1]
Real Estate and Accumulated Depreciation, Initial Cost of Land	15,152,000	[1]
Real Estate and Accumulated Depreciation, Initial Cost of Buildings and Improvements	0	[1]
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Carrying Costs	0	[1]
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Improvements	325,537,000	[1]
Real Estate and Accumulated Depreciation, Carrying Amount of Land	15,152,000	[1]
Real Estate and Accumulated Depreciation, Carrying Amount of Buildings and Improvements	325,537,000	[1]
Real Estate and Accumulated Depreciation, Carrying Amount of Land and Buildings and Improvements	340,689,000	[1]
Real Estate and Accumulated Depreciation, Accumulated Depreciation	25,581,000	[1]
Real Estate And Accumulated Depreciation, Year Acquired	2007
VA3 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Amount of Encumbrances	0	[1]
Real Estate and Accumulated Depreciation, Initial Cost of Land	9,000,000	[1]
Real Estate and Accumulated Depreciation, Initial Cost of Buildings and Improvements	172,881,000	[1]
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Carrying Costs	0	[1]
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Improvements	5,481,000	[1]
Real Estate and Accumulated Depreciation, Carrying Amount of Land	9,000,000	[1]
Real Estate and Accumulated Depreciation, Carrying Amount of Buildings and Improvements	178,362,000	[1]
Real Estate and Accumulated Depreciation, Carrying Amount of Land and Buildings and Improvements	187,362,000	[1]
Real Estate and Accumulated Depreciation, Accumulated Depreciation	58,261,000	[1]
Real Estate And Accumulated Depreciation, Year Acquired	2003
VA4 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Amount of Encumbrances	0	[1]
Real Estate and Accumulated Depreciation, Initial Cost of Land	6,800,000	[1]
Real Estate and Accumulated Depreciation, Initial Cost of Buildings and Improvements	140,575,000	[1]
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Carrying Costs	0	[1]
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Improvements	8,675,000	[1]
Real Estate and Accumulated Depreciation, Carrying Amount of Land	6,800,000	[1]
Real Estate and Accumulated Depreciation, Carrying Amount of Buildings and Improvements	149,250,000	[1]
Real Estate and Accumulated Depreciation, Carrying Amount of Land and Buildings and Improvements	156,050,000	[1]
Real Estate and Accumulated Depreciation, Accumulated Depreciation	45,135,000	[1]
Real Estate and Accumulated Depreciation, Year of Construction	2005
Real Estate And Accumulated Depreciation, Year Acquired	2005
Operating Properties [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Amount of Encumbrances	115,000,000
Real Estate and Accumulated Depreciation, Initial Cost of Land	82,632,000
Real Estate and Accumulated Depreciation, Initial Cost of Buildings and Improvements	1,621,369,000
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Carrying Costs	1,161,000
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Improvements	1,002,170,000
Real Estate and Accumulated Depreciation, Carrying Amount of Land	83,793,000
Real Estate and Accumulated Depreciation, Carrying Amount of Buildings and Improvements	2,623,539,000
Real Estate and Accumulated Depreciation, Carrying Amount of Land and Buildings and Improvements	2,707,332,000
Real Estate and Accumulated Depreciation, Accumulated Depreciation	504,869,000
SC1 Phase IIB [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Amount of Encumbrances	0	[1]
Real Estate and Accumulated Depreciation, Initial Cost of Land	5,049,000
Real Estate and Accumulated Depreciation, Initial Cost of Buildings and Improvements	95,591,000	[1]
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Carrying Costs	0	[1]
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Improvements	0	[1]
Real Estate and Accumulated Depreciation, Carrying Amount of Land	5,049,000	[1]
Real Estate and Accumulated Depreciation, Carrying Amount of Buildings and Improvements	95,591,000	[1]
Real Estate and Accumulated Depreciation, Carrying Amount of Land and Buildings and Improvements	100,640,000	[1]
Real Estate and Accumulated Depreciation, Accumulated Depreciation	0	[1]
Real Estate And Accumulated Depreciation, Year Acquired	2007
ACC7 Phase II to IV [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Amount of Encumbrances	0
Real Estate and Accumulated Depreciation, Initial Cost of Land	6,966,000
Real Estate and Accumulated Depreciation, Initial Cost of Buildings and Improvements	85,384,000
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Carrying Costs	0
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Improvements	0
Real Estate and Accumulated Depreciation, Carrying Amount of Land	6,966,000
Real Estate and Accumulated Depreciation, Carrying Amount of Buildings and Improvements	85,384,000
Real Estate and Accumulated Depreciation, Carrying Amount of Land and Buildings and Improvements	92,350,000
Real Estate and Accumulated Depreciation, Accumulated Depreciation	0
Real Estate And Accumulated Depreciation, Year Acquired	2011
CH2 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Amount of Encumbrances	0
Real Estate and Accumulated Depreciation, Initial Cost of Land	14,393,000
Real Estate and Accumulated Depreciation, Initial Cost of Buildings and Improvements	102,703,000
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Carrying Costs	0
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Improvements	0
Real Estate and Accumulated Depreciation, Carrying Amount of Land	14,393,000
Real Estate and Accumulated Depreciation, Carrying Amount of Buildings and Improvements	102,703,000
Real Estate and Accumulated Depreciation, Carrying Amount of Land and Buildings and Improvements	117,096,000
Real Estate and Accumulated Depreciation, Accumulated Depreciation	0
Real Estate And Accumulated Depreciation, Year Acquired	2013
NJ1 Phase II [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Amount of Encumbrances	0	[1]
Real Estate and Accumulated Depreciation, Initial Cost of Land	4,318,000
Real Estate and Accumulated Depreciation, Initial Cost of Buildings and Improvements	34,894,000	[1]
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Carrying Costs	0	[1]
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Improvements	0	[1]
Real Estate and Accumulated Depreciation, Carrying Amount of Land	4,318,000	[1]
Real Estate and Accumulated Depreciation, Carrying Amount of Buildings and Improvements	34,894,000	[1]
Real Estate and Accumulated Depreciation, Carrying Amount of Land and Buildings and Improvements	39,212,000	[1]
Real Estate and Accumulated Depreciation, Accumulated Depreciation	0	[1]
Real Estate And Accumulated Depreciation, Year Acquired	2007
ACC8 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Amount of Encumbrances	0
Real Estate and Accumulated Depreciation, Initial Cost of Land	3,785,000
Real Estate and Accumulated Depreciation, Initial Cost of Buildings and Improvements	505,000
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Carrying Costs	0
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Improvements	0
Real Estate and Accumulated Depreciation, Carrying Amount of Land	3,785,000
Real Estate and Accumulated Depreciation, Carrying Amount of Buildings and Improvements	505,000
Real Estate and Accumulated Depreciation, Carrying Amount of Land and Buildings and Improvements	4,290,000
Real Estate and Accumulated Depreciation, Accumulated Depreciation	0
Real Estate And Accumulated Depreciation, Year Acquired	2007
SC2 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Amount of Encumbrances	0	[1]
Real Estate and Accumulated Depreciation, Initial Cost of Land	5,377,000
Real Estate and Accumulated Depreciation, Initial Cost of Buildings and Improvements	0	[1]
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Carrying Costs	0	[1]
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Improvements	0	[1]
Real Estate and Accumulated Depreciation, Carrying Amount of Land	5,377,000	[1]
Real Estate and Accumulated Depreciation, Carrying Amount of Buildings and Improvements	0	[1]
Real Estate and Accumulated Depreciation, Carrying Amount of Land and Buildings and Improvements	5,377,000	[1]
Real Estate and Accumulated Depreciation, Accumulated Depreciation	0	[1]
Real Estate And Accumulated Depreciation, Year Acquired	2007
Development Properties [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Amount of Encumbrances	0
Real Estate and Accumulated Depreciation, Initial Cost of Land	39,888,000
Real Estate and Accumulated Depreciation, Initial Cost of Buildings and Improvements	319,077,000
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Carrying Costs	0
Real Estate and Accumulated Depreciation, Costs Capitalized Subsequent to Acquisition, Improvements	0
Real Estate and Accumulated Depreciation, Carrying Amount of Land	39,888,000
Real Estate and Accumulated Depreciation, Carrying Amount of Buildings and Improvements	319,077,000
Real Estate and Accumulated Depreciation, Carrying Amount of Land and Buildings and Improvements	358,965,000
Real Estate and Accumulated Depreciation, Accumulated Depreciation	$0
Minimum [Member] | ACC5 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Year of Construction	2009	[1]
Minimum [Member] | ACC6 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Year of Construction	2009	[1]
Minimum [Member] | CH1 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Year of Construction	2007	[1]
Minimum [Member] | NJ1 Phase I [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Year of Construction	2008	[1]
Minimum [Member] | SC1 Phase I and IIA [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Year of Construction	2008	[1]
Minimum [Member] | VA3 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Year of Construction	2003	[1]
Maximum [Member] | ACC5 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Year of Construction	2010	[1]
Maximum [Member] | ACC6 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Year of Construction	2011	[1]
Maximum [Member] | CH1 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Year of Construction	2008	[1]
Maximum [Member] | NJ1 Phase I [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Year of Construction	2010	[1]
Maximum [Member] | SC1 Phase I and IIA [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Year of Construction	2014	[1]
Maximum [Member] | VA3 [Member]
Real Estate and Accumulated Depreciation [Line Items]
Real Estate and Accumulated Depreciation, Year of Construction	2004	[1]
[1]	The subsidiaries that own these data centers and development properties are guarantors of the Company's Unsecured Notes and Unsecured Credit Facility.
[2]	The subsidiary that owns this data center is encumbered by the Company's ACC3 Term Loan.

Schedule_III_Consolidated_Real3

Schedule III - Consolidated Real Estate and Accumulated Depreciation Reconciliation of Real Estate Assets and Accumulated Depreciation (Details) (USD $)	12 Months Ended
In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
SEC Schedule III, Real Estate and Accumulated Depreciation Disclosure [Abstract]
Real estate assets Balance, beginning of period	$2,799,010	$2,607,630	$2,507,381
Additions - property acquisitions	0	14,186	3,830
Additions - improvements	267,357	177,194	96,419
Deductions - write offs	-70
Real estate assets Balance, end of period	3,066,297	2,799,010	2,607,630
Accumulated depreciation Balance, beginning of period	413,394	325,740	242,245
Additions - depreciation	91,545	87,654	83,495
Deductions - write offs	-70
Accumulated depreciation Balance, end of period	$504,869	$413,394	$325,740