Revenue - Changes in Contract Assets and Liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Unbilled Receivables
Beginning Balance	$ 90	$ 5,245
Reclassifications to billed receivables	(3,983)	(11,157)
Revenues recognized in excess of period billings	4,037	6,002
Ending Balance	144	90
Deferred Revenue
Beginning Balance	113,319	118,414
Revenues recognized from balances held at the beginning of the period	(65,225)	(33,381)
Revenues deferred from period collections on unfulfilled performance obligations	12,225	31,625
Revenues recognized from period collections	(9,685)	(3,339)
Ending Balance	$ 50,634	$ 113,319