Income Taxes - Schedule of Components of Income Tax Benefit (Details) - USD ($) $ in Thousands	9 Months Ended		12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2018	Dec. 31, 2016
Current:
Federal	$ 23,217		$ (5,264)	$ 8,476
State	2,444		2,376	2,083
Deferred:
Federal	(30,695)		(54,528)	(38,286)
State	(4,251)		(8,832)	(4,776)
Total income tax benefit	$ (9,285)	$ (17,769)	$ (66,248)	$ (32,503)