Income Taxes - Provision (benefit) for income taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Current Income Tax Expense (Benefit):
Federal	$ 0	$ (4)	$ 334
State	96	132	686
Foreign	465	65	0
Current income tax provision (benefit)	561	193	1,020
Deferred Income Tax Expense (Benefit):
Federal	0	80,586	10,241
State	(53)	1,119	526
Foreign	(3,904)	(1,993)	(1,494)
Deferred income tax provision (benefit)	(3,957)	79,712	9,273
Tax provision (benefit):
Federal	0	80,582	10,575
State	43	1,251	1,212
Foreign	(3,439)	(1,928)	(1,494)
Income tax provision (benefit)	$ (3,396)	$ 79,905	$ 10,293