Income Taxes - Components of Income Tax Expense (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Current
Federal									$ 2,973	$ 4,509	$ 24,258
State									5,304	5,547	5,666
Total deferred expense									8,277	10,056	29,924
Deferred
Federal									13,175	9,702	14,885
State									1,341	(399)	233
Total deferred expense									14,516	9,303	15,118
Effective income tax rate	$ 7,451	$ 8,020	$ 2,491	$ 4,831	$ 5,109	$ 28	$ 6,820	$ 7,402	$ 22,793	$ 19,359	$ 45,042