Acquisitions (Narrative) (Details)		3 Months Ended	6 Months Ended	12 Months Ended
	Jun. 16, 2015 USD ($) property customer	Dec. 31, 2013 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Jul. 23, 2014 USD ($)
Business Acquisition [Line Items]
Ownership interest			85.80%	85.80%
Cash consideration paid for acquisition		$ 47,963,000		$ 320,058,000	$ 201,145,000
Carpathia Hosting, Inc. [Member]
Business Acquisition [Line Items]
Ownership interest	100.00%
Acquisition costs	$ 366,700,000
Number of customers of acquired entity | customer	230
Number of domestic data centers acquired | property	8
Number of international data centers acquired | property	5
Tax basis of ducutible amount of goodwill acquired			$ 16,600,000	16,600,000
Amoritization of intangible assets in the remainder of the year			11,000,000	11,000,000
Amoritization of intangible assets in 2017			11,000,000	11,000,000
Amoritization of intangible assets in 2018			8,800,000	8,800,000
Amoritization of intangible assets in 2019			6,700,000	6,700,000
Amoritization of intangible assets in 2020			6,700,000	6,700,000
Revenue since acquisition			49,200,000
Net income since acquisition			$ 2,300,000
Deluth, Georgia [Member]
Business Acquisition [Line Items]
Acquisition costs				3,800,000
Deluth, Georgia [Member] | Land [Member]
Business Acquisition [Line Items]
Acquisition costs				1,900,000
Deluth, Georgia [Member] | Building and Building Improvements [Member]
Business Acquisition [Line Items]
Acquisition costs				$ 1,900,000
Senior Notes [Member]
Business Acquisition [Line Items]
Notes issued						$ 300,000,000