Income Taxes - Components of Income Tax Expense (Benefit) from Continuing Operations (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
Federal									$ 49,053	$ 37,134	$ 43,027
State									8,171	5,384	4,568
Total current tax expense									57,224	42,518	47,595
Deferred tax
Federal									(4,045)	(177)	(19,355)
State									(791)	24	(906)
Total deferred tax benefit									(4,836)	(153)	(20,261)
Total tax expense	$ 34,787	$ 10,293	$ 8,123	$ (815)	$ 10,753	$ 10,616	$ 10,466	$ 10,530	$ 52,388	$ 42,365	$ 27,334