v3.25.1
Loans and Allowance for Credit Losses - Loan Balances by Year of Origination and Internally Assigned Risk Rating (Details) - USD ($)
$ in Thousands
 3 Months Ended 12 Months Ended
Mar. 31, 2025
Mar. 31, 2024
Dec. 31, 2024
Total Loan Balance      
Current fiscal year $ 298,890   $ 893,015
Year two 901,514   1,134,650
Year three 1,087,612   1,191,528
Year four 1,165,428   897,782
Year five 876,014   421,743
More than five years 2,188,191   1,885,462
Revolving 1,282,043   1,284,808
Revolving-Term 36,657   33,970
Total 7,836,349   7,742,958
Year-to-date Gross Charge-offs      
Current fiscal year 198   839
Year two 0   191
Year three 160   288
Year four 231   1,338
Year five 41   91
More than five years 12   6,837
Revolving 23   1,118
Revolving-Term 219   1,486
Total 884 $ 6,939 12,188
Pass      
Total Loan Balance      
Current fiscal year 298,890   892,431
Year two 899,688   1,128,069
Year three 1,074,112   1,171,403
Year four 1,145,565   870,715
Year five 849,546   417,507
More than five years 2,083,653   1,775,175
Revolving 1,239,095   1,243,868
Revolving-Term 33,249   30,962
Total 7,623,798   7,530,130
Special mention      
Total Loan Balance      
Current fiscal year 0   0
Year two 1,259   2,020
Year three 4,153   17,638
Year four 16,103   2,112
Year five 2,725   157
More than five years 63,373   65,401
Revolving 7,984   11,322
Revolving-Term 264   268
Total 95,861   98,918
Substandard      
Total Loan Balance      
Current fiscal year 0   584
Year two 567   4,561
Year three 9,347   2,487
Year four 3,760   24,589
Year five 23,743   3,196
More than five years 41,165   44,886
Revolving 34,964   26,717
Revolving-Term 3,144   2,740
Total 116,690   109,760
Doubtful      
Total Loan Balance      
Current fiscal year 0   0
Year two 0   0
Year three 0   0
Year four 0   366
Year five 0   883
More than five years 0   0
Revolving 0   2,901
Revolving-Term 0   0
Total 0   4,150
Commercial Loans | Commercial real estate      
Total Loan Balance      
Current fiscal year 146,775   278,187
Year two 270,301   289,081
Year three 296,522   363,529
Year four 351,124   415,621
Year five 412,182   215,632
More than five years 1,254,645   1,110,490
Revolving 44,516   35,991
Revolving-Term 0   0
Total 2,776,065   2,708,531
Year-to-date Gross Charge-offs      
Current fiscal year 0   0
Year two 0   0
Year three 0   0
Year four 0   0
Year five 0   0
More than five years 0   5,205
Revolving 0   0
Revolving-Term 0   0
Total 0 5,205 5,205
Commercial Loans | Commercial and industrial      
Total Loan Balance      
Current fiscal year 27,389   120,143
Year two 123,508   148,100
Year three 136,108   195,756
Year four 192,902   152,971
Year five 145,744   31,312
More than five years 209,881   197,426
Revolving 495,559   505,929
Revolving-Term 0   0
Total 1,331,091   1,351,637
Year-to-date Gross Charge-offs      
Current fiscal year 0   0
Year two 0   78
Year three 0   0
Year four 172   1,235
Year five 0   0
More than five years 0   91
Revolving 0   1,032
Revolving-Term 0   0
Total 172 1,128 2,436
Commercial Loans | Commercial construction      
Total Loan Balance      
Current fiscal year 36,944   119,355
Year two 131,909   121,816
Year three 104,310   73,851
Year four 72,631   14,911
Year five 13,054   884
More than five years 2,111   2,139
Revolving 6,910   8,310
Revolving-Term 0   0
Total 367,869   341,266
Year-to-date Gross Charge-offs      
Current fiscal year 0   0
Year two 0   0
Year three 0   0
Year four 30   0
Year five 0   0
More than five years 0   0
Revolving 0   0
Revolving-Term 0   0
Total 30 0 0
Commercial Loans | Business banking      
Total Loan Balance      
Current fiscal year 46,684   149,624
Year two 147,247   233,041
Year three 225,252   226,654
Year four 220,919   177,683
Year five 172,626   76,643
More than five years 404,821   345,327
Revolving 95,875   92,981
Revolving-Term 1,058   1,305
Total 1,314,482   1,303,258
Year-to-date Gross Charge-offs      
Current fiscal year 0   0
Year two 0   79
Year three 106   124
Year four 0   0
Year five 34   56
More than five years 3   1,486
Revolving 0   0
Revolving-Term 0   0
Total 143 98 1,745
Commercial Loans | Pass | Commercial real estate      
Total Loan Balance      
Current fiscal year 146,775   278,187
Year two 270,301   287,081
Year three 290,555   362,174
Year four 349,795   413,781
Year five 410,355   213,384
More than five years 1,190,080   1,040,703
Revolving 44,262   35,737
Revolving-Term 0   0
Total 2,702,123   2,631,047
Commercial Loans | Pass | Commercial and industrial      
Total Loan Balance      
Current fiscal year 27,389   119,580
Year two 122,961   147,007
Year three 132,157   194,363
Year four 192,211   131,877
Year five 125,781   30,093
More than five years 188,982   175,359
Revolving 454,870   466,640
Revolving-Term 0   0
Total 1,244,351   1,264,919
Commercial Loans | Pass | Commercial construction      
Total Loan Balance      
Current fiscal year 36,944   119,355
Year two 131,040   121,816
Year three 104,310   57,853
Year four 56,662   14,911
Year five 13,054   884
More than five years 2,111   2,139
Revolving 6,910   8,310
Revolving-Term 0   0
Total 351,031   325,268
Commercial Loans | Pass | Business banking      
Total Loan Balance      
Current fiscal year 46,684   149,603
Year two 146,837   230,784
Year three 222,869   225,318
Year four 219,286   173,763
Year five 168,159   76,087
More than five years 391,390   332,707
Revolving 95,632   92,756
Revolving-Term 354   597
Total 1,291,211   1,281,615
Commercial Loans | Special mention | Commercial real estate      
Total Loan Balance      
Current fiscal year 0   0
Year two 0   2,000
Year three 2,000   370
Year four 350   1,840
Year five 1,827   0
More than five years 44,064   46,104
Revolving 254   254
Revolving-Term 0   0
Total 48,495   50,568
Commercial Loans | Special mention | Commercial and industrial      
Total Loan Balance      
Current fiscal year 0   0
Year two 0   20
Year three 2,077   1,221
Year four 691   142
Year five 12   10
More than five years 14,558   14,896
Revolving 7,696   11,033
Revolving-Term 0   0
Total 25,034   27,322
Commercial Loans | Special mention | Commercial construction      
Total Loan Balance      
Current fiscal year 0   0
Year two 869   0
Year three 0   15,998
Year four 14,963   0
Year five 0   0
More than five years 0   0
Revolving 0   0
Revolving-Term 0   0
Total 15,832   15,998
Commercial Loans | Special mention | Business banking      
Total Loan Balance      
Current fiscal year 0   0
Year two 390   0
Year three 76   49
Year four 99   130
Year five 886   147
More than five years 4,657   4,302
Revolving 34   35
Revolving-Term 264   268
Total 6,406   4,931
Commercial Loans | Substandard | Commercial real estate      
Total Loan Balance      
Current fiscal year 0   0
Year two 0   0
Year three 3,967   985
Year four 979   0
Year five 0   1,834
More than five years 20,501   23,683
Revolving 0   0
Revolving-Term 0   0
Total 25,447   26,502
Commercial Loans | Substandard | Commercial and industrial      
Total Loan Balance      
Current fiscal year 0   563
Year two 547   1,073
Year three 1,874   172
Year four 0   20,586
Year five 19,951   740
More than five years 6,341   7,171
Revolving 32,993   25,355
Revolving-Term 0   0
Total 61,706   55,660
Commercial Loans | Substandard | Commercial construction      
Total Loan Balance      
Current fiscal year 0   0
Year two 0   0
Year three 0   0
Year four 1,006   0
Year five 0   0
More than five years 0   0
Revolving 0   0
Revolving-Term 0   0
Total 1,006   0
Commercial Loans | Substandard | Business banking      
Total Loan Balance      
Current fiscal year 0   21
Year two 20   2,257
Year three 2,307   1,287
Year four 1,534   3,790
Year five 3,581   409
More than five years 8,774   8,318
Revolving 209   190
Revolving-Term 440   440
Total 16,865   16,712
Commercial Loans | Doubtful | Commercial real estate      
Total Loan Balance      
Current fiscal year 0   0
Year two 0   0
Year three 0   0
Year four 0   0
Year five 0   414
More than five years 0   0
Revolving 0   0
Revolving-Term 0   0
Total 0   414
Commercial Loans | Doubtful | Commercial and industrial      
Total Loan Balance      
Current fiscal year 0   0
Year two 0   0
Year three 0   0
Year four 0   366
Year five 0   469
More than five years 0   0
Revolving 0   2,901
Revolving-Term 0   0
Total 0   3,736
Commercial Loans | Doubtful | Commercial construction      
Total Loan Balance      
Current fiscal year 0   0
Year two 0   0
Year three 0   0
Year four 0   0
Year five 0   0
More than five years 0   0
Revolving 0   0
Revolving-Term 0   0
Total 0   0
Commercial Loans | Doubtful | Business banking      
Total Loan Balance      
Current fiscal year 0   0
Year two 0   0
Year three 0   0
Year four 0   0
Year five 0   0
More than five years 0   0
Revolving 0   0
Revolving-Term 0   0
Total 0   0
Consumer Loans | Consumer real estate      
Total Loan Balance      
Current fiscal year 38,600   217,250
Year two 221,466   335,763
Year three 319,479   324,389
Year four 321,530   133,347
Year five 129,810   95,504
More than five years 314,803   229,462
Revolving 573,994   570,558
Revolving-Term 28,995   27,236
Total 1,948,677   1,933,509
Year-to-date Gross Charge-offs      
Current fiscal year 0   0
Year two 0   0
Year three 38   0
Year four 0   0
Year five 0   9
More than five years 5   37
Revolving 23   86
Revolving-Term 96   1,216
Total 162 139 1,348
Consumer Loans | Other consumer      
Total Loan Balance      
Current fiscal year 2,498   8,456
Year two 7,083   6,849
Year three 5,941   7,349
Year four 6,322   3,249
Year five 2,598   1,768
More than five years 1,930   618
Revolving 65,189   71,039
Revolving-Term 6,604   5,429
Total 98,165   104,757
Year-to-date Gross Charge-offs      
Current fiscal year 198   839
Year two 0   34
Year three 16   164
Year four 29   103
Year five 7   26
More than five years 4   18
Revolving 0   0
Revolving-Term 123   270
Total 377 $ 369 1,454
Consumer Loans | Pass | Consumer real estate      
Total Loan Balance      
Current fiscal year 38,600   217,250
Year two 221,466   334,532
Year three 318,280   324,346
Year four 321,289   133,155
Year five 129,619   95,301
More than five years 309,314   223,799
Revolving 572,232   569,386
Revolving-Term 26,317   24,940
Total 1,937,117   1,922,709
Consumer Loans | Pass | Other consumer      
Total Loan Balance      
Current fiscal year 2,498   8,456
Year two 7,083   6,849
Year three 5,941   7,349
Year four 6,322   3,228
Year five 2,578   1,758
More than five years 1,776   468
Revolving 65,189   71,039
Revolving-Term 6,578   5,425
Total 97,965   104,572
Consumer Loans | Special mention | Consumer real estate      
Total Loan Balance      
Current fiscal year 0   0
Year two 0   0
Year three 0   0
Year four 0   0
Year five 0   0
More than five years 94   99
Revolving 0   0
Revolving-Term 0   0
Total 94   99
Consumer Loans | Special mention | Other consumer      
Total Loan Balance      
Current fiscal year 0   0
Year two 0   0
Year three 0   0
Year four 0   0
Year five 0  
More than five years 0   0
Revolving 0   0
Revolving-Term  
Total 0   0
Consumer Loans | Substandard | Consumer real estate      
Total Loan Balance      
Current fiscal year 0   0
Year two 0   1,231
Year three 1,199   43
Year four 241   192
Year five 191   203
More than five years 5,395   5,564
Revolving 1,762   1,172
Revolving-Term 2,678   2,296
Total 11,466   10,701
Consumer Loans | Substandard | Other consumer      
Total Loan Balance      
Current fiscal year 0   0
Year two 0   0
Year three 0   0
Year four 0   21
Year five 20   10
More than five years 154   150
Revolving 0   0
Revolving-Term 26   4
Total 200   185
Consumer Loans | Doubtful | Consumer real estate      
Total Loan Balance      
Current fiscal year 0   0
Year two 0   0
Year three 0   0
Year four 0   0
Year five 0   0
More than five years 0   0
Revolving 0   0
Revolving-Term 0   0
Total 0   0
Consumer Loans | Doubtful | Other consumer      
Total Loan Balance      
Current fiscal year 0   0
Year two 0   0
Year three 0   0
Year four 0   0
Year five 0   0
More than five years 0   0
Revolving 0   0
Revolving-Term 0   0
Total $ 0   $ 0