Acquisitions (Narrative) (Details)		3 Months Ended	9 Months Ended
	Jun. 16, 2015 USD ($) property customer	Sep. 30, 2015 USD ($)	Sep. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)	Jul. 23, 2014 USD ($)
Business Acquisition [Line Items]
Ownership interest		85.70%	85.70%
Amoritization of intangible assets in the remainder of the year		$ 5,900,000	$ 5,900,000
Amoritization of intangible assets in 2016		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
Cash consideration paid for acquisition			$ 252,156,000	$ 156,008,000
Carpathia Hosting, Inc. [Member]
Business Acquisition [Line Items]
Ownership interest	100.00%
Acquisition costs	$ 354,400,000
Number of customers of acquired entity | customer	230
Number of domestic data centers acquired | property	8
Number of international data centers acquired | property	5
Revenue since acquisition		25,900,000
Net income since acquisition		$ 700,000
Senior Notes [Member]
Business Acquisition [Line Items]
Notes issued					$ 300,000,000