Income Taxes - Income Before Income Tax Expense (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Taxes [Line Items]
Income (loss) before income taxes	$ (161,500)	$ 89,921	$ (25,044)	$ 120,617
Domestic
Income Taxes [Line Items]
Income (loss) before income taxes		89,582	(29,538)	116,693
Foreign
Income Taxes [Line Items]
Income (loss) before income taxes		$ 339	$ 4,494	$ 3,924