Comprehensive Income (Loss) - Summary of Changes in Accumulated Other Comprehensive Income (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period	$ 1,108,587	$ 827,014	$ 763,784
Net unrealized gain on securities reclassified from available for sale to held to maturity	0	0	2,784
Other comprehensive income (loss)	10,681	(78,025)	(8,133)
Amounts reclassified from accumulated other comprehensive income			(6)
Balance at end of period	1,169,369	1,108,587	827,014
Total
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period	(74,761)	3,264	11,397
Net unrealized gain on securities reclassified from available for sale to held to maturity			0
Other comprehensive income (loss)	10,681	(78,025)	(8,133)
Other comprehensive (loss) income before reclassifications			(8,127)
Balance at end of period	(64,080)	(74,761)	3,264
Unrealized Gains (Losses)  on Available- for-Sale Securities
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period	(76,729)	745	11,402
Net unrealized gain on securities reclassified from available for sale to held to maturity			(2,784)
Other comprehensive income (loss)	11,159	(77,474)	(7,873)
Other comprehensive (loss) income before reclassifications			(7,867)
Amounts reclassified from accumulated other comprehensive income			(6)
Balance at end of period	(65,570)	(76,729)	745
Amortization of Gain on Debt Securities Reclassified to Held to Maturity
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period	1,968	2,519	0
Net unrealized gain on securities reclassified from available for sale to held to maturity			2,784
Other comprehensive income (loss)	(478)	(551)	(265)
Other comprehensive (loss) income before reclassifications			(265)
Amounts reclassified from accumulated other comprehensive income			0
Balance at end of period	1,490	1,968	2,519
Unrealized Gains  (Losses) on  Derivatives
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period	0	0	25
Net unrealized gain on securities reclassified from available for sale to held to maturity			0
Other comprehensive income (loss)	0	0	(25)
Other comprehensive (loss) income before reclassifications			(25)
Amounts reclassified from accumulated other comprehensive income			0
Balance at end of period	0	0	0
Pension Items
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period	0	0	(30)
Net unrealized gain on securities reclassified from available for sale to held to maturity			0
Other comprehensive income (loss)	0	0	30
Other comprehensive (loss) income before reclassifications			30
Amounts reclassified from accumulated other comprehensive income			0
Balance at end of period	$ 0	$ 0	$ 0