Annual report [Section 13 and 15(d), not S-K Item 405]

Securities - Summary of Debt Securities Available for Sale in an Unrealized Loss Position for Which an Allowance for Credit Losses Has Not Been Recorded (Detail)

v3.25.4
Securities - Summary of Debt Securities Available for Sale in an Unrealized Loss Position for Which an Allowance for Credit Losses Has Not Been Recorded (Detail)
$ in Thousands
Dec. 31, 2025
USD ($)
Security
Dec. 31, 2024
USD ($)
Security
Summary of Investment Holdings [Line Items]    
Available-for-Sale Within One Year, Gross Unrealized Loss $ (46) $ (1,447)
Available-for-Sale Within One Year, Estimated Fair Value $ 9,628 $ 144,646
Available-for-Sale Within One Year, Number of Securities | Security 3 42
Available-for-Sale More than One Year, Gross Unrealized Loss $ (64,198) $ (98,219)
Available-for-Sale More than One Year, Estimated Fair Value $ 571,822 $ 630,005
Available-for-Sale More than One Year, Number of Securities | Security 189 195
Available-for-Sale, Gross Unrealized Loss $ (64,244) $ (99,666)
Available-for-Sale, Estimated Fair Value $ 581,450 $ 774,651
Available-for-Sale, Number of Securities | Security 192 237
U.S. Treasury securities    
Summary of Investment Holdings [Line Items]    
Available-for-Sale Within One Year, Gross Unrealized Loss   $ (61)
Available-for-Sale Within One Year, Estimated Fair Value $ 4,999 $ 13,603
Available-for-Sale Within One Year, Number of Securities | Security 1 6
Available-for-Sale More than One Year, Gross Unrealized Loss $ (157) $ (460)
Available-for-Sale More than One Year, Estimated Fair Value $ 10,351 $ 9,771
Available-for-Sale More than One Year, Number of Securities | Security 3 3
Available-for-Sale, Gross Unrealized Loss $ (157) $ (521)
Available-for-Sale, Estimated Fair Value $ 15,350 $ 23,374
Available-for-Sale, Number of Securities | Security 4 9
Mortgage-backed securities - residential    
Summary of Investment Holdings [Line Items]    
Available-for-Sale Within One Year, Gross Unrealized Loss $ (46) $ (271)
Available-for-Sale Within One Year, Estimated Fair Value $ 4,629 $ 23,276
Available-for-Sale Within One Year, Number of Securities | Security 2 10
Available-for-Sale More than One Year, Gross Unrealized Loss $ (38,695) $ (61,372)
Available-for-Sale More than One Year, Estimated Fair Value $ 322,912 $ 351,793
Available-for-Sale More than One Year, Number of Securities | Security 114 114
Available-for-Sale, Gross Unrealized Loss $ (38,741) $ (61,643)
Available-for-Sale, Estimated Fair Value $ 327,541 $ 375,069
Available-for-Sale, Number of Securities | Security 116 124
Mortgage-backed securities - commercial    
Summary of Investment Holdings [Line Items]    
Available-for-Sale Within One Year, Gross Unrealized Loss   $ (447)
Available-for-Sale Within One Year, Estimated Fair Value   $ 19,092
Available-for-Sale Within One Year, Number of Securities | Security   5
Available-for-Sale More than One Year, Gross Unrealized Loss $ (11,295) $ (12,608)
Available-for-Sale More than One Year, Estimated Fair Value $ 54,316 $ 41,817
Available-for-Sale More than One Year, Number of Securities | Security 16 14
Available-for-Sale, Gross Unrealized Loss $ (11,295) $ (13,055)
Available-for-Sale, Estimated Fair Value $ 54,316 $ 60,909
Available-for-Sale, Number of Securities | Security 16 19
Collateralized mortgage obligations    
Summary of Investment Holdings [Line Items]    
Available-for-Sale Within One Year, Gross Unrealized Loss   $ (645)
Available-for-Sale Within One Year, Estimated Fair Value   $ 76,963
Available-for-Sale Within One Year, Number of Securities | Security   18
Available-for-Sale More than One Year, Gross Unrealized Loss $ (5,933) $ (8,756)
Available-for-Sale More than One Year, Estimated Fair Value $ 50,264 $ 54,020
Available-for-Sale More than One Year, Number of Securities | Security 24 24
Available-for-Sale, Gross Unrealized Loss $ (5,933) $ (9,401)
Available-for-Sale, Estimated Fair Value $ 50,264 $ 130,983
Available-for-Sale, Number of Securities | Security 24 42
Debt securities    
Summary of Investment Holdings [Line Items]    
Available-for-Sale Within One Year, Gross Unrealized Loss   $ (23)
Available-for-Sale Within One Year, Estimated Fair Value   $ 11,712
Available-for-Sale Within One Year, Number of Securities | Security   3
Available-for-Sale More than One Year, Gross Unrealized Loss $ (1,105) $ (3,946)
Available-for-Sale More than One Year, Estimated Fair Value $ 65,954 $ 107,595
Available-for-Sale More than One Year, Number of Securities | Security 13 21
Available-for-Sale, Gross Unrealized Loss $ (1,105) $ (3,969)
Available-for-Sale, Estimated Fair Value $ 65,954 $ 119,307
Available-for-Sale, Number of Securities | Security 13 24
Total U.S. government agency and sponsored agency obligations    
Summary of Investment Holdings [Line Items]    
Available-for-Sale Within One Year, Gross Unrealized Loss $ (46) $ (1,386)
Available-for-Sale Within One Year, Estimated Fair Value $ 4,629 $ 131,043
Available-for-Sale Within One Year, Number of Securities | Security 2 36
Available-for-Sale More than One Year, Gross Unrealized Loss $ (57,028) $ (86,682)
Available-for-Sale More than One Year, Estimated Fair Value $ 493,446 $ 555,225
Available-for-Sale More than One Year, Number of Securities | Security 167 173
Available-for-Sale, Gross Unrealized Loss $ (57,074) $ (88,068)
Available-for-Sale, Estimated Fair Value $ 498,075 $ 686,268
Available-for-Sale, Number of Securities | Security 169 209
Municipal bonds-tax exempt    
Summary of Investment Holdings [Line Items]    
Available-for-Sale More than One Year, Gross Unrealized Loss $ (7,013) $ (11,077)
Available-for-Sale More than One Year, Estimated Fair Value $ 68,025 $ 65,009
Available-for-Sale More than One Year, Number of Securities | Security 19 19
Available-for-Sale, Gross Unrealized Loss $ (7,013) $ (11,077)
Available-for-Sale, Estimated Fair Value $ 68,025 $ 65,009
Available-for-Sale, Number of Securities | Security 19 19