Comprehensive Income (Loss) - Components of Other Comprehensive Income (Loss) (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Before Tax Amount
Other comprehensive loss, net	$ (13,256)	$ (38,224)	$ (15,672)	$ (107,325)
Tax Benefit
Other comprehensive loss, net	3,562	10,115	4,307	28,280
Net of Tax Amount
Other comprehensive loss, net of tax	(9,694)	(28,109)	(11,365)	(79,045)
AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-Sale, Parent [Member]
Before Tax Amount
Unrealized losses on available for sale securities arising during the period	(13,104)	(38,037)	(15,174)	(106,759)
Tax Benefit
Unrealized losses on available for sale securities arising during the period	3,521	10,065	4,173	28,134
Net of Tax Amount
Net current period other comprehensive loss	(9,583)	(27,972)	(11,001)	(78,625)
Other comprehensive loss, net of tax	(9,583)	(27,972)	(11,001)	(78,625)
Amortization of Gain on Debt Securities Reclassified to Held to Maturity
Before Tax Amount
Other comprehensive loss, net	(152)	(187)	(498)	(566)
Tax Benefit
Other comprehensive loss, net	41	50	134	146
Net of Tax Amount
Other comprehensive loss, net of tax	$ (111)	$ (137)	$ (364)	$ (420)