Quarterly report pursuant to Section 13 or 15(d)

Fair Value Measurements - Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail)

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Fair Value Measurements - Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($)
$ in Thousands
Sep. 30, 2023
Dec. 31, 2022
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Securities available for sale $ 817,242 $ 853,838
Derivative financial instruments, Assets $ 8,600 $ 7,500
Derivative Asset, Statement of Financial Position [Extensible Enumeration] Prepaid Expense and Other Assets Prepaid Expense and Other Assets
Derivative financial instruments, Liabilities $ 8,500 $ 7,400
Derivative Liability, Statement of Financial Position [Extensible Enumeration] Accrued Liabilities and Other Liabilities Accrued Liabilities and Other Liabilities
U.S. Treasury securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Securities available for sale $ 70,922 $ 48,026
Collateralized mortgage obligations    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Securities available for sale 86,258 85,485
Debt securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Securities available for sale 129,919 138,499
Total U.S. government agency and sponsored agency obligations    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Securities available for sale 684,869 740,428
Municipal bonds-tax exempt    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Securities available for sale 61,451 65,384
Recurring Basis    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Securities available for sale 817,242 853,838
Recurring Basis | U.S. Treasury securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Securities available for sale 70,922 48,026
Recurring Basis | Derivative financial instruments    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative financial instruments, Assets 8,602 7,507
Derivative financial instruments, Liabilities 8,493 7,375
Recurring Basis | Collateralized mortgage obligations    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Securities available for sale 86,258 85,485
Recurring Basis | Debt securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Securities available for sale 129,919 138,499
Recurring Basis | Total U.S. government agency and sponsored agency obligations    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Securities available for sale 684,869 740,428
Recurring Basis | Municipal bonds-tax exempt    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Securities available for sale 61,451 65,384
Recurring Basis | Mortgage-backed securities - commercial | Mortgage-backed securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Securities available for sale 45,966 51,292
Recurring Basis | Mortgage-backed securities - residential | Mortgage-backed securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Securities available for sale 422,726 465,152
Recurring Basis | Quoted Prices in Active Markets for Identical Assets    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Securities available for sale 70,922 48,026
Recurring Basis | Quoted Prices in Active Markets for Identical Assets | U.S. Treasury securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Securities available for sale 70,922 48,026
Recurring Basis | Quoted Prices in Active Markets for Identical Assets | Derivative financial instruments    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative financial instruments, Assets 0 0
Derivative financial instruments, Liabilities 0 0
Recurring Basis | Quoted Prices in Active Markets for Identical Assets | Collateralized mortgage obligations    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Securities available for sale 0 0
Recurring Basis | Quoted Prices in Active Markets for Identical Assets | Debt securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Securities available for sale 0 0
Recurring Basis | Quoted Prices in Active Markets for Identical Assets | Total U.S. government agency and sponsored agency obligations    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Securities available for sale 0 0
Recurring Basis | Quoted Prices in Active Markets for Identical Assets | Municipal bonds-tax exempt    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Securities available for sale 0 0
Recurring Basis | Quoted Prices in Active Markets for Identical Assets | Mortgage-backed securities - commercial | Mortgage-backed securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Securities available for sale 0 0
Recurring Basis | Quoted Prices in Active Markets for Identical Assets | Mortgage-backed securities - residential | Mortgage-backed securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Securities available for sale 0 0
Recurring Basis | Significant Observable Inputs with No Active Market with Identical Characteristics    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Securities available for sale 746,320 805,812
Recurring Basis | Significant Observable Inputs with No Active Market with Identical Characteristics | U.S. Treasury securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Securities available for sale 0 0
Recurring Basis | Significant Observable Inputs with No Active Market with Identical Characteristics | Derivative financial instruments    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative financial instruments, Assets 8,602 7,507
Derivative financial instruments, Liabilities 8,493 7,375
Recurring Basis | Significant Observable Inputs with No Active Market with Identical Characteristics | Collateralized mortgage obligations    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Securities available for sale 86,258 85,485
Recurring Basis | Significant Observable Inputs with No Active Market with Identical Characteristics | Debt securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Securities available for sale 129,919 138,499
Recurring Basis | Significant Observable Inputs with No Active Market with Identical Characteristics | Total U.S. government agency and sponsored agency obligations    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Securities available for sale 684,869 740,428
Recurring Basis | Significant Observable Inputs with No Active Market with Identical Characteristics | Municipal bonds-tax exempt    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Securities available for sale 61,451 65,384
Recurring Basis | Significant Observable Inputs with No Active Market with Identical Characteristics | Mortgage-backed securities - commercial | Mortgage-backed securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Securities available for sale 45,966 51,292
Recurring Basis | Significant Observable Inputs with No Active Market with Identical Characteristics | Mortgage-backed securities - residential | Mortgage-backed securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Securities available for sale 422,726 465,152
Recurring Basis | Significant Unobservable Inputs    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Securities available for sale 0 0
Recurring Basis | Significant Unobservable Inputs | U.S. Treasury securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Securities available for sale 0 0
Recurring Basis | Significant Unobservable Inputs | Derivative financial instruments    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative financial instruments, Assets 0 0
Derivative financial instruments, Liabilities 0 0
Recurring Basis | Significant Unobservable Inputs | Collateralized mortgage obligations    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Securities available for sale 0 0
Recurring Basis | Significant Unobservable Inputs | Debt securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Securities available for sale 0 0
Recurring Basis | Significant Unobservable Inputs | Total U.S. government agency and sponsored agency obligations    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Securities available for sale 0 0
Recurring Basis | Significant Unobservable Inputs | Municipal bonds-tax exempt    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Securities available for sale 0 0
Recurring Basis | Significant Unobservable Inputs | Mortgage-backed securities - commercial | Mortgage-backed securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Securities available for sale 0 0
Recurring Basis | Significant Unobservable Inputs | Mortgage-backed securities - residential | Mortgage-backed securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Securities available for sale $ 0 $ 0