Securities - Gross Unrealized Losses, Aggregated by Investment Category and Length of Time (Detail) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Losses, Less Than Twelve Months	$ (343)	$ (6,965)
Fair Value, Less Than Twelve Months	15,778	99,357
Gross Unrealized Losses, Twelve Months and Over	(39,253)	(41,501)
Fair Value, Twelve Months and Over	351,494	286,095
Gross Unrealized Losses, Total	(39,596)	(48,466)
Fair Value, Total	367,272	385,452
U.S. Treasury [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Losses, Less Than Twelve Months	(19)	(207)
Fair Value, Less Than Twelve Months	727	9,121
Gross Unrealized Losses, Twelve Months and Over	(7,684)	(9,622)
Fair Value, Twelve Months and Over	86,785	85,557
Gross Unrealized Losses, Total	(7,703)	(9,829)
Fair Value, Total	87,512	94,678
U.S. Government Agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Losses, Less Than Twelve Months	(48)	(1,081)
Fair Value, Less Than Twelve Months	1,952	24,560
Gross Unrealized Losses, Twelve Months and Over	(13,949)	(15,969)
Fair Value, Twelve Months and Over	128,156	114,906
Gross Unrealized Losses, Total	(13,997)	(17,050)
Fair Value, Total	130,108	139,466
Mortgage-backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Losses, Less Than Twelve Months	(28)	(2,454)
Fair Value, Less Than Twelve Months	3,099	26,905
Gross Unrealized Losses, Twelve Months and Over	(12,000)	(11,687)
Fair Value, Twelve Months and Over	83,221	60,022
Gross Unrealized Losses, Total	(12,028)	(14,141)
Fair Value, Total	86,320	86,927
State and Local Governments [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross Unrealized Losses, Less Than Twelve Months	(248)	(3,223)
Fair Value, Less Than Twelve Months	10,000	38,771
Gross Unrealized Losses, Twelve Months and Over	(5,620)	(4,223)
Fair Value, Twelve Months and Over	53,332	25,610
Gross Unrealized Losses, Total	(5,868)	(7,446)
Fair Value, Total	$ 63,332	$ 64,381

Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for more than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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Amount of accumulated unrealized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for 12 months or longer, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for less than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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