Income Taxes - Summary of Income Tax Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Current expense:
Federal	$ 96,057	$ 95,317	$ 51,147
State	48,463	36,457	28,898
Total current expense	144,520	131,774	80,045
Deferred (benefit) expense:
Federal	(3,109)	10,444	(17,463)
State	(1,951)	4,784	5,683
Total deferred expense	(5,060)	15,228	(11,780)
Income tax expense	$ 139,460	$ 147,002	$ 68,265