Income Taxes Expense - Components of the Income Tax Expense (Benefit) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Current
Federal	$ 29,893	$ 29,333	$ 26,772
State	11,234	10,930	5,621
Deferred
Federal	2,200	(4,551)	(2,450)
State	(1,629)	(1,281)	(760)
Income tax expense	$ 41,698	$ 34,431	$ 29,183