Other Comprehensive Income (Loss) - Components of Other Comprehensive Income (loss) Pre-Tax and After-Tax (Detail) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2022	Mar. 31, 2022	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2022	Jun. 30, 2021
After-tax
Other comprehensive income (loss)	$ (29,656)	$ (42,910)	$ 7,996	$ (16,910)	$ (72,566)	$ (8,914)
AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-sale, Parent
Pre-tax
Unrealized holding gains (losses) arising during the period	(40,272)		10,264		(97,433)	(12,161)
Less: Reclassification adjustments for (gains) losses realized in net income (loss)	949		245		1,213	447
Other comprehensive income (loss)	(39,323)		10,509		(96,220)	(11,714)
Tax
Unrealized holding gains (losses) arising during the period	(9,900)		2,454		(23,952)	(2,907)
Income taxes	233		59		298	107
Other comprehensive income (loss)	(9,667)		2,513		(23,654)	(2,800)
After-tax
Unrealized holding gains (losses) arising during the period	(30,372)		7,810		(73,481)	(9,254)
Less: Reclassification adjustments for (gains) losses realized in net income (loss)	716		186		915	340
Other comprehensive income (loss)	$ (29,656)		$ 7,996		$ (72,566)	$ (8,914)

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