Quarterly report [Sections 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, 2026
Dec. 31, 2025
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Securities available for sale $ 869,499 $ 880,624
Derivative financial instruments 4,397 2,719
Derivative financial instruments 3,138 2,568
U.S. Treasury securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Securities available for sale 225,051 128,710
Collateralized mortgage obligations    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Securities available for sale 151,059 183,955
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 582,503 683,889
Municipal bonds-tax exempt    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Securities available for sale 61,945 68,025
Recurring Basis    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Securities available for sale 869,499 880,624
Recurring Basis | U.S. Treasury securities    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Securities available for sale 225,051 128,710
Recurring Basis | Derivative financial instruments    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Derivative financial instruments 4,397 2,719
Derivative financial instruments 3,138 2,568
Recurring Basis | Collateralized mortgage obligations    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Securities available for sale 151,059 183,955
Recurring Basis | Other U.S. government agency obligations    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Securities available for sale 34,083 65,954
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 582,503 683,889
Recurring Basis | Municipal bonds-tax exempt    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Securities available for sale 61,945 68,025
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 63,814 60,572
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 333,547 373,408
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 225,051 128,710
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 225,051 128,710
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 0 0
Derivative financial instruments 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 | Other U.S. government 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 | 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 644,448 751,914
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 4,397 2,719
Derivative financial instruments 3,138 2,568
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 151,059 183,955
Recurring Basis | Significant Observable Inputs with No Active Market with Identical Characteristics | Other U.S. government agency obligations    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Securities available for sale 34,083 65,954
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 582,503 683,889
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 61,945 68,025
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 63,814 60,572
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 333,547 373,408
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 0 0
Derivative financial instruments 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 | Other U.S. government 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 | 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