Income Taxes - Components of the Company's Income Tax Expense (Benefit) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Current taxes:
Federal	$ 25,974	$ 26,247	$ 23,700
State	7,443	7,288	7,083
Deferred taxes	(9,491)	1,148	3,155
Total income taxes	$ 23,926	$ 34,683	$ 33,938