v3.26.1
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
Jun. 30, 2026
USD ($)
Security
Dec. 31, 2025
USD ($)
Security
Summary of Investment Holdings [Line Items]    
Available-for-Sale Within One Year, Gross Unrealized Loss $ (1,128) $ (46)
Available-for-Sale Within One Year, Estimated Fair Value $ 273,123 $ 9,628
Available-for-Sale Within One Year, Number of Securities | Security 64 3
Available-for-Sale More than One Year, Gross Unrealized Loss $ (65,582) $ (64,198)
Available-for-Sale More than One Year, Estimated Fair Value $ 497,104 $ 571,822
Available-for-Sale More than One Year, Number of Securities | Security 179 189
Available-for-Sale, Gross Unrealized Loss $ (66,710) $ (64,244)
Available-for-Sale, Estimated Fair Value $ 770,227 $ 581,450
Available-for-Sale, Number of Securities | Security 243 192
U.S. Treasury securities    
Summary of Investment Holdings [Line Items]    
Available-for-Sale Within One Year, Gross Unrealized Loss $ (423)  
Available-for-Sale Within One Year, Estimated Fair Value $ 174,452 $ 4,999
Available-for-Sale Within One Year, Number of Securities | Security 39 1
Available-for-Sale More than One Year, Gross Unrealized Loss $ (62) $ (157)
Available-for-Sale More than One Year, Estimated Fair Value $ 10,440 $ 10,351
Available-for-Sale More than One Year, Number of Securities | Security 3 3
Available-for-Sale, Gross Unrealized Loss $ (485) $ (157)
Available-for-Sale, Estimated Fair Value $ 184,892 $ 15,350
Available-for-Sale, Number of Securities | Security 42 4
Mortgage-backed securities - residential    
Summary of Investment Holdings [Line Items]    
Available-for-Sale Within One Year, Gross Unrealized Loss $ (291) $ (46)
Available-for-Sale Within One Year, Estimated Fair Value $ 24,434 $ 4,629
Available-for-Sale Within One Year, Number of Securities | Security 6 2
Available-for-Sale More than One Year, Gross Unrealized Loss $ (40,139) $ (38,695)
Available-for-Sale More than One Year, Estimated Fair Value $ 297,345 $ 322,912
Available-for-Sale More than One Year, Number of Securities | Security 115 114
Available-for-Sale, Gross Unrealized Loss $ (40,430) $ (38,741)
Available-for-Sale, Estimated Fair Value $ 321,779 $ 327,541
Available-for-Sale, Number of Securities | Security 121 116
Mortgage-backed securities - commercial    
Summary of Investment Holdings [Line Items]    
Available-for-Sale Within One Year, Gross Unrealized Loss $ (166)  
Available-for-Sale Within One Year, Estimated Fair Value $ 12,221  
Available-for-Sale Within One Year, Number of Securities | Security 4  
Available-for-Sale More than One Year, Gross Unrealized Loss $ (11,503) $ (11,295)
Available-for-Sale More than One Year, Estimated Fair Value $ 48,288 $ 54,316
Available-for-Sale More than One Year, Number of Securities | Security 14 16
Available-for-Sale, Gross Unrealized Loss $ (11,669) $ (11,295)
Available-for-Sale, Estimated Fair Value $ 60,509 $ 54,316
Available-for-Sale, Number of Securities | Security 18 16
Collateralized mortgage obligations    
Summary of Investment Holdings [Line Items]    
Available-for-Sale Within One Year, Gross Unrealized Loss $ (212)  
Available-for-Sale Within One Year, Estimated Fair Value $ 52,053  
Available-for-Sale Within One Year, Number of Securities | Security 13  
Available-for-Sale More than One Year, Gross Unrealized Loss $ (6,053) $ (5,933)
Available-for-Sale More than One Year, Estimated Fair Value $ 41,783 $ 50,264
Available-for-Sale More than One Year, Number of Securities | Security 21 24
Available-for-Sale, Gross Unrealized Loss $ (6,265) $ (5,933)
Available-for-Sale, Estimated Fair Value $ 93,836 $ 50,264
Available-for-Sale, Number of Securities | Security 34 24
Debt securities    
Summary of Investment Holdings [Line Items]    
Available-for-Sale Within One Year, Gross Unrealized Loss $ (36)  
Available-for-Sale Within One Year, Estimated Fair Value $ 9,963  
Available-for-Sale Within One Year, Number of Securities | Security 2  
Available-for-Sale More than One Year, Gross Unrealized Loss $ (503) $ (1,105)
Available-for-Sale More than One Year, Estimated Fair Value $ 32,062 $ 65,954
Available-for-Sale More than One Year, Number of Securities | Security 7 13
Available-for-Sale, Gross Unrealized Loss $ (539) $ (1,105)
Available-for-Sale, Estimated Fair Value $ 42,025 $ 65,954
Available-for-Sale, Number of Securities | Security 9 13
Total U.S. government agency and sponsored agency obligations    
Summary of Investment Holdings [Line Items]    
Available-for-Sale Within One Year, Gross Unrealized Loss $ (705) $ (46)
Available-for-Sale Within One Year, Estimated Fair Value $ 98,671 $ 4,629
Available-for-Sale Within One Year, Number of Securities | Security 25 2
Available-for-Sale More than One Year, Gross Unrealized Loss $ (58,198) $ (57,028)
Available-for-Sale More than One Year, Estimated Fair Value $ 419,478 $ 493,446
Available-for-Sale More than One Year, Number of Securities | Security 157 167
Available-for-Sale, Gross Unrealized Loss $ (58,903) $ (57,074)
Available-for-Sale, Estimated Fair Value $ 518,149 $ 498,075
Available-for-Sale, Number of Securities | Security 182 169
Municipal bonds-tax exempt    
Summary of Investment Holdings [Line Items]    
Available-for-Sale More than One Year, Gross Unrealized Loss $ (7,322) $ (7,013)
Available-for-Sale More than One Year, Estimated Fair Value $ 67,186 $ 68,025
Available-for-Sale More than One Year, Number of Securities | Security 19 19
Available-for-Sale, Gross Unrealized Loss $ (7,322) $ (7,013)
Available-for-Sale, Estimated Fair Value $ 67,186 $ 68,025
Available-for-Sale, Number of Securities | Security 19 19