Income Taxes - Income Tax Expense (Benefit) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Federal
Current									$ 4,256	$ 18,918	$ 13,616
Deferred									(4,273)	(406)	3,517
Total Federal									(17)	18,512	17,133
State
Current									145	589	720
Deferred									(129)	25	(8)
Total State									16	614	712
Total Federal and State	$ 5,702	$ 3,323	$ (11,793)	$ 2,767	$ 5,091	$ 4,743	$ 5,070	$ 4,222	$ (1)	$ 19,126	$ 17,845