Income Taxes - Income Tax Expense (Benefit) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Federal:
Current	$ (113)	$ 2,200	$ (12)
Deferred	52,367	15,310	(3,248)
Total Federal	52,254	17,510	(3,260)
State:
Current	(2,798)	(995)	(2,118)
Deferred (included in Federal above)	0	0	0
Total State	(2,798)	(995)	(2,118)
Total	$ 49,456	$ 16,515	$ (5,378)