Revenue - Narrative (Details) - USD ($) $ in Thousands		3 Months Ended								12 Months Ended
	Jan. 01, 2018	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Jan. 01, 2019
Summary of Significant Accounting Policies
Accumulated deficit		$ (1,709,747)				$ (1,611,334)				$ (1,709,747)	$ (1,611,334)
Income tax benefit										91,942	95,855	$ 16,026
Revenues		261,000	$ 621,180	$ 477,210	$ 128,193	269,503	$ 619,820	$ 445,420	$ 128,964	1,487,583	1,463,707	1,359,074
Long-term contracts
Summary of Significant Accounting Policies
Revenues										198,507	212,584	$ 188,375
Contract with customer, liability	$ 111,600												$ 100,800
Unearned contract with customer revenue recognized										161,000	109,700
Performance obligation		$ 85,100				$ 100,800				85,100	100,800
Difference between Revenue Guidance in Effect before and after Topic 606 | Accounting Standards Update 2014-09
Summary of Significant Accounting Policies
Accumulated deficit	4,900
Income tax benefit	$ 1,300									29	(198)
Revenues										$ 100	$ (900)