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Investment Securities - Analysis of Amortized Cost and Estimated Fair Values of Securities Available for Sale (Detail) - USD ($) $ in Thousands	Jun. 30, 2025	Dec. 31, 2024
Investment Securities [Line Items]
Amortized Cost	$ 1,205,127	$ 1,267,747
Gross Unrealized Gains	7,664	5,438
Gross Unrealized Losses	(101,082)	(125,562)
Debt Securities, Available-for-Sale	1,111,709	1,147,623
US Government Agencies Residential Mortgage-backed Securities [Member]
Investment Securities [Line Items]
Amortized Cost	2,846	3,096
Gross Unrealized Gains	22	14
Gross Unrealized Losses	(176)	(212)
Debt Securities, Available-for-Sale	2,692	2,898
US Government Agency Debt Securities Commercial [Member]
Investment Securities [Line Items]
Amortized Cost	757,242	779,232
Gross Unrealized Gains	4,562	2,489
Gross Unrealized Losses	(48,794)	(57,546)
Debt Securities, Available-for-Sale	713,010	724,175
Residential Mortgage Backed Securities [Member]
Investment Securities [Line Items]
Amortized Cost	373,287	413,434
Gross Unrealized Gains	1,559	1,481
Gross Unrealized Losses	(49,533)	(64,331)
Debt Securities, Available-for-Sale	325,313	350,584
US Government-sponsored Enterprises Debt Securities [Member]
Investment Securities [Line Items]
Amortized Cost	1,000	1,000
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(32)	(54)
Debt Securities, Available-for-Sale	968	946
Obligations of States and Political Subdivisions [Member]
Investment Securities [Line Items]
Amortized Cost	8,014	8,510
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(753)	(983)
Debt Securities, Available-for-Sale	7,261	7,527
Corporate Debt Securities [Member]
Investment Securities [Line Items]
Amortized Cost	62,738	62,475
Gross Unrealized Gains	1,521	1,454
Gross Unrealized Losses	(1,794)	(2,436)
Debt Securities, Available-for-Sale	$ 62,465	$ 61,493

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Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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