Provision for income taxes - Provision for income taxes (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Income tax expense:
Deferred income tax benefit	$ (151)	$ (250)
Total provision for income taxes	1,185	1,919
Expected tax expense, at the U.S. federal statutory income tax rate of 21%	$ 1,037	$ 1,677
U.S. federal statutory income tax rate	21.00%	21.00%
State income taxes	$ 145	$ 240
Other, net	3	2
Total provision for income taxes	1,185	1,919
Disclosure Other Comprehensive Income Loss Tax Effects Allocation to Component Of Other Comprehensive Income Loss [Abstract]
Other comprehensive loss - marketable securities	(1)	(13)
Total	$ 1,184	$ 1,906