Revenue from Contracts with Customers - Schedule of Contract with Customer, Asset and Liability (Details) - USD ($) $ in Thousands		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenue from Contract with Customer [Abstract]
Contract assets		$ 158,243	$ 122,621	$ 130,697
Contract assets, non-current		0	0
Contract liabilities		(552,290)	(524,156)	$ (489,242)
Contract liabilities, non-current		(2,069)	0
Deferred revenue (1)	[1]	0	(47,328)
Net contract liabilities		$ (396,116)	$ (448,863)

[1] Represents deferred revenue on service contracts, which was included in “Accrued expenses and other” and “Other long-term liabilities” in the Consolidated Balance Sheet as of December 31 2017. For the periods after December 31, 2017, these amounts are included within “Contract liabilities.”