Fair Value - Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Fair Value Of Assets And Liabilities Measured On Recurring Basis [Line Items]
Available-for-sale securities	$ 1,042,176	$ 919,648
Cash collateral held by counterparty and netting adjustments	(8,852)	(6,406)
Cash collateral held by counterparty and netting adjustments	(8,852)	(6,406)
U.S. Government Sponsored Entities [Member]
Fair Value Of Assets And Liabilities Measured On Recurring Basis [Line Items]
Available-for-sale securities	75,132	33,087
U.S. Treasury securities [Member]
Fair Value Of Assets And Liabilities Measured On Recurring Basis [Line Items]
Available-for-sale securities	95,039	89,256
Government-Sponsored Residential Mortgage-Backed Securities [Member]
Fair Value Of Assets And Liabilities Measured On Recurring Basis [Line Items]
Available-for-sale securities	603,847	529,143
Private Label Residential Mortgage-Backed Securities [Member]
Fair Value Of Assets And Liabilities Measured On Recurring Basis [Line Items]
Available-for-sale securities	129,065	137,841
Corporate [Member]
Fair Value Of Assets And Liabilities Measured On Recurring Basis [Line Items]
Available-for-sale securities	56,095	49,683
Small Business Administration Loan Pools [Member]
Fair Value Of Assets And Liabilities Measured On Recurring Basis [Line Items]
Available-for-sale securities	6,873	7,727
State and Political Subdivisions [Member]
Fair Value Of Assets And Liabilities Measured On Recurring Basis [Line Items]
Available-for-sale securities	76,125	72,911
Fair Value, Measurements, Recurring [Member] | Level 1 [Member]
Fair Value Of Assets And Liabilities Measured On Recurring Basis [Line Items]
Derivative assets	(8,852)	(6,406)
Cash collateral held by counterparty and netting adjustments	(8,852)	(6,406)
Equity securities with readily determinable fair value	648	674
Total other assets	648	674
Total assets	86,835	83,524
Derivative liabilities	189	(454)
Cash collateral held by counterparty and netting adjustments	189	(454)
Total liabilities	189	(454)
Fair Value, Measurements, Recurring [Member] | Level 1 [Member] | U.S. Treasury securities [Member]
Fair Value Of Assets And Liabilities Measured On Recurring Basis [Line Items]
Available-for-sale securities	95,039	89,256
Fair Value, Measurements, Recurring [Member] | Level 2 [Member]
Fair Value Of Assets And Liabilities Measured On Recurring Basis [Line Items]
Derivative assets	$ 9,671	$ 7,002
Derivative Asset, Statement of Financial Position [Extensible Enumeration]	Other Assets	Other Assets
Total assets	$ 956,808	$ 837,394
Derivative liabilities	$ 3,786	$ 3,656
Derivative Liability, Statement of Financial Position [Extensible Enumeration]	Accounts Payable and Other Accrued Liabilities	Accounts Payable and Other Accrued Liabilities
Total liabilities	$ 3,786	$ 3,656
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | U.S. Government Sponsored Entities [Member]
Fair Value Of Assets And Liabilities Measured On Recurring Basis [Line Items]
Available-for-sale securities	75,132	33,087
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Government-Sponsored Residential Mortgage-Backed Securities [Member]
Fair Value Of Assets And Liabilities Measured On Recurring Basis [Line Items]
Available-for-sale securities	603,847	529,143
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Private Label Residential Mortgage-Backed Securities [Member]
Fair Value Of Assets And Liabilities Measured On Recurring Basis [Line Items]
Available-for-sale securities	129,065	137,841
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Corporate [Member]
Fair Value Of Assets And Liabilities Measured On Recurring Basis [Line Items]
Available-for-sale securities	56,095	49,683
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | Small Business Administration Loan Pools [Member]
Fair Value Of Assets And Liabilities Measured On Recurring Basis [Line Items]
Available-for-sale securities	6,873	7,727
Fair Value, Measurements, Recurring [Member] | Level 2 [Member] | State and Political Subdivisions [Member]
Fair Value Of Assets And Liabilities Measured On Recurring Basis [Line Items]
Available-for-sale securities	$ 76,125	$ 72,911