Income Taxes - Components of Income Tax Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Current tax provision:
Federal	$ (1,048)	$ (87,961)	$ 78,782
State	388	(8,429)	9,878
Foreign	4,895	5,032	5,256
Total current	4,235	(91,358)	93,916
Deferred tax provision:
Federal	(1,570)	154,817	(87,584)
State	(210)	18,902	(11,622)
Foreign	(768)	187	(1,228)
Total deferred	(2,548)	173,906	(100,434)
Total income tax expense (benefit)	$ 1,687	$ 82,548	$ (6,518)