CONSOLIDATED STATEMENTS OF COMPREHENSIVE (LOSS) INCOME (UNAUDITED) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018
Statement of Comprehensive Income [Abstract]
Net (loss) income	$ (48,752)	$ 234,956	$ 62,242	$ 95,150	$ 111,319	$ 90,090	$ 248,446	$ 296,559
Foreign currency translation adjustment	(2,064)			3,052			5,347	(5,815)
Other comprehensive (loss) income	(2,064)	$ 3,610	$ 3,801	3,052	$ (3,364)	$ (5,503)	5,347	(5,815)
Comprehensive (loss) income	$ (50,816)			$ 98,202			$ 253,793	$ 290,744