Components of Income Tax Expense (Benefit) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Expenses [Line Items]
Current income tax expense, Federal	$ (1,928)	$ 5,324	$ 10,481
Current income tax expense, State	1,369	3,677	2,308
Current income tax expense, Total	(559)	9,001	12,789
Deferred income tax expense (benefit), Federal	3,878	(489)	(3,422)
Deferred income tax expense (benefit), State	1,067	(673)	(1,014)
Deferred income tax expense (benefit), Total	4,945	(1,162)	(4,436)
Income tax expense	$ 4,386	$ 7,839	$ 8,353