Summary of Significant Accounting Policies Summary of Significant Accounting Policies - Revenue - Narrative (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Amortization	$ 99,445	$ 58,774
Commissions asset
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Capitalized Contract Cost, Amortization Period	3 years
Contract Duration Term	1 year
Data Center Business
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Percentage of consolidated revenue	5.00%
Intake Costs asset
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Capitalized Contract Cost, Amortization Period	3 years
Accounting Standards Update 2014-09
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption	$ 30,233