Income Taxes - Summary of Income Tax Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Current Income Tax Expense:
Federal	$ (5,380)	$ (3,530)	$ 103,993
State	13,015	9,772	10,308
Current Income Tax Expense (Benefit), Total	7,635	6,242	114,301
Deferred Income Tax Expense (Benefit):
Federal	48,287	(60,547)	(33,470)
State	72	1,346	(1,692)
Deferred Income Tax Expense (Benefit), Total	48,359	(59,201)	(35,162)
INCOME TAXES	$ 55,994	$ (52,959)	$ 79,139