Summary of Significant Accounting Policies Summary of Goodwill Activity (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2018 USD ($)
Goodwill [Roll Forward]
Goodwill - Beginning Balance	$ 3,389,595
Impact of Change in Foreign Exchange Rates	(11,270)
Goodwill - Ending Balance	3,378,325
Telx Acquisition
Goodwill [Roll Forward]
Goodwill - Beginning Balance	330,845
Impact of Change in Foreign Exchange Rates	0
Goodwill - Ending Balance	330,845
European Portfolio Acquisition
Goodwill [Roll Forward]
Goodwill - Beginning Balance	466,604
Impact of Change in Foreign Exchange Rates	(11,270)
Goodwill - Ending Balance	455,334
DFT Company
Goodwill [Roll Forward]
Goodwill - Beginning Balance	2,592,146
Impact of Change in Foreign Exchange Rates	0
Goodwill - Ending Balance	$ 2,592,146