Summary of Significant Accounting Policies (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015	Dec. 31, 2014
Summary Of Significant Accounting Policies [Line Items]
Deferred costs, net	$ 31,367		$ 30,042
Unsecured credit facility, net	607,105		520,956
Senior notes, net of discount and debt issuance costs	$ 291,186		290,852
Useful life of property	40 years
Depreciation expense from operation	$ 20,700	$ 12,800
Real estate cost capitalized excluding interest cost	2,400	3,300
Real estate interest cost capitalized incurred	2,800	2,000
Amortization of below market lease	100	0
Annual amortization for intangible assets for 2015	10,100
Annual amortization for intangible assets for 2016	12,200
Amortization of the deferred financing costs	813	791
Deferred leasing costs, net	5,873		6,263
In Place Leases [Member]
Summary Of Significant Accounting Policies [Line Items]
Amortization of lease costs	400	400
Tenant Relationship [Member]
Summary Of Significant Accounting Policies [Line Items]
Amoritzation of intangible assets	3,000	300
Amortization adjustment	(1,000)		(700)
Platform [Member]
Summary Of Significant Accounting Policies [Line Items]
Amoritzation of intangible assets	800	0
Trade Names [Member]
Summary Of Significant Accounting Policies [Line Items]
Amoritzation of intangible assets	300	0
Qualitytech, LP [Member]
Summary Of Significant Accounting Policies [Line Items]
Deferred costs, net	31,367		30,042
Unsecured credit facility, net	607,105		520,956
Senior notes, net of discount and debt issuance costs	291,186		290,852
Amortization of the deferred financing costs	813	791
Real Estate Assets [Member]
Summary Of Significant Accounting Policies [Line Items]
Depreciation expense from operation	17,700	10,900
Non-Real Estate Assets [Member]
Summary Of Significant Accounting Policies [Line Items]
Depreciation expense from operation	$ 3,000	$ 1,900
Minimum [Member] | Real Property [Member]
Summary Of Significant Accounting Policies [Line Items]
Useful life of property	20 years
Maximum [Member] | Real Property [Member]
Summary Of Significant Accounting Policies [Line Items]
Useful life of property	40 years
Maximum [Member] | Leasehold Improvements [Member]
Summary Of Significant Accounting Policies [Line Items]
Useful life of property	20 years
Unsecured Credit Facility [Member] | Accounting Standards Update 201503 [Member]
Summary Of Significant Accounting Policies [Line Items]
Deferred costs, net			(3,100)
Unsecured credit facility, net			3,100
Senior Note [Member]
Summary Of Significant Accounting Policies [Line Items]
Interest rate	5.875%
Senior notes due	2022
Deferred leasing costs, net	$ 6,800
Senior Note [Member] | Accounting Standards Update 201503 [Member]
Summary Of Significant Accounting Policies [Line Items]
Deferred costs, net			(7,100)
Senior notes, net of discount and debt issuance costs			7,100
Princeton Facility [Member]
Summary Of Significant Accounting Policies [Line Items]
Deferred leasing costs, net				$ 2,700
Carpathia Hosting, Inc. [Member] | Tenant Relationship [Member]
Summary Of Significant Accounting Policies [Line Items]
Amortization adjustment	$ (1,000)		$ (700)