Income Taxes - Components of Consolidated Income Tax Expense (Detail) - 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
Current tax expense
Federal									$ 22,104	$ 20,403	$ 13,109
State									14,586	12,655	9,323
Current tax expense, Total									36,690	33,058	22,432
Deferred tax expense
Federal									(9,500)	695	1,842
State									(4,654)	997	758
Deferred tax benefit, Total									(14,154)	1,692	2,600
Total tax expense	$ 8,750	$ 6,622	$ 1,092	$ 6,072	$ 8,826	$ 9,386	$ 7,443	$ 9,095	$ 22,536	$ 34,750	$ 25,032