Revenue Recognition Narrative (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Revenue Recognition and Deferred Revenue [Abstract]
Contract with Customer, Asset, Gross	$ 14,200	$ 11,300
Contract with Customer, Liability	136,700	71,100
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Deferred Revenue, Current	87,293	41,438
Retained Earnings (Accumulated Deficit)	(471,812)	$ (337,873)
Difference between Revenue Guidance in Effect before and after Topic 606 [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Deferred Revenue	15,000
Deferred Revenue, Current	6,000
Retained Earnings (Accumulated Deficit)	$ 11,000