Income Taxes (Details) - USD ($) $ in Thousands		12 Months Ended
	Dec. 22, 2017	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Current:
Federal		$ 42,411	$ 28,130	$ 20,167
State		6,629	5,739	2,996
Total current		49,040	33,869	23,163
Deferred:
Federal		(21,865)	(5,135)	(875)
State		(2,295)	(595)	1,200
Deferred tax liability remeasurement		0	0	(875)	$ 2,610
Total deferred		(24,160)	(5,730)	(550)
Total provision		$ 24,880	$ 28,139	$ 22,613
Statutory federal income tax (as a percent)	21.00%	21.00%	21.00%	21.00%	35.00%