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Allowance for Credit Losses - Loan Balances by Year of Origination and Internally Assigned Risk Rating (Details) - USD ($) $ in Thousands | Sep. 30, 2021 | Dec. 31, 2020
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Financing Receivable, Credit Quality Indicator [Line Items] |  |
Current fiscal year | $ 1,035,267 | $ 1,360,684
Year two | 854,925 | 1,214,746
Year three | 1,107,652 | 831,734
Year four | 688,325 | 565,201
Year five | 462,114 | 610,556
More than five years | 1,692,697 | 1,572,826
Revolving | 1,100,863 | 1,041,199
Revolving-Term | 28,244 | 28,914
Total | 6,970,087 | 7,225,860
Pass |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Current fiscal year | 1,029,863 | 1,355,292
Year two | 847,760 | 1,136,716
Year three | 1,017,394 | 792,352
Year four | 653,430 | 502,350
Year five | 394,438 | 494,436
More than five years | 1,416,288 | 1,337,222
Revolving | 1,081,538 | 1,011,297
Revolving-Term | 24,651 | 25,724
Total | 6,465,362 | 6,655,389
Special mention |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Current fiscal year | 162 | 5,274
Year two | 4,448 | 47,302
Year three | 34,953 | 19,350
Year four | 8,994 | 24,802
Year five | 39,973 | 57,026
More than five years | 112,175 | 91,677
Revolving | 10,866 | 24,296
Revolving-Term | 121 | 124
Total | 211,692 | 269,851
Substandard |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Current fiscal year | 5,242 | 118
Year two | 2,717 | 30,083
Year three | 45,441 | 20,032
Year four | 25,901 | 33,648
Year five | 27,703 | 57,105
More than five years | 164,234 | 137,398
Revolving | 8,459 | 5,606
Revolving-Term | 3,472 | 3,066
Total | 283,169 | 287,056
Doubtful |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Current fiscal year | 0 | 0
Year two | 0 | 645
Year three | 9,864 | 0
Year four | 0 | 4,401
Year five | 0 | 1,989
More than five years | 0 | 6,529
Revolving | 0 | 0
Revolving-Term | 0 | 0
Total | 9,864 | 13,564
Commercial |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Total | 5,423,964 | 5,673,707
Commercial | Commercial real estate |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Current fiscal year | 255,876 | 334,086
Year two | 325,327 | 476,203
Year three | 493,611 | 417,944
Year four | 365,129 | 320,140
Year five | 281,897 | 415,184
More than five years | 937,114 | 780,560
Revolving | 43,826 | 47,830
Revolving-Term | 0 | 0
Total | 2,702,780 | 2,791,947
Commercial | Commercial and industrial |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Current fiscal year | 406,445 | 457,828
Year two | 159,516 | 215,457
Year three | 175,718 | 145,290
Year four | 102,677 | 82,249
Year five | 48,349 | 28,488
More than five years | 141,411 | 221,609
Revolving | 444,082 | 408,631
Revolving-Term |  | 0
Total | 1,478,198 | 1,559,552
Commercial | Commercial construction |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Current fiscal year | 100,774 | 132,813
Year two | 136,589 | 230,907
Year three | 179,924 | 63,535
Year four | 33,903 | 2,921
Year five | 996 | 6,346
More than five years | 12,024 | 16,777
Revolving | 21,714 | 12,778
Revolving-Term |  | 0
Total | 485,924 | 466,077
Commercial | Business banking |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Current fiscal year | 173,313 | 296,357
Year two | 115,055 | 156,473
Year three | 155,033 | 128,250
Year four | 122,227 | 91,363
Year five | 84,905 | 82,202
More than five years | 344,047 | 298,779
Revolving | 104,339 | 105,549
Revolving-Term | 1,206 | 1,094
Total | 1,100,125 | 1,160,067
Commercial | Pass | Commercial real estate |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Current fiscal year | 255,876 | 334,086
Year two | 323,514 | 422,800
Year three | 443,487 | 394,963
Year four | 341,387 | 277,724
Year five | 224,258 | 307,321
More than five years | 716,460 | 615,217
Revolving | 42,326 | 46,330
Revolving-Term | 0 | 0
Total | 2,347,308 | 2,398,441
Commercial | Pass | Commercial and industrial |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Current fiscal year | 401,200 | 454,131
Year two | 156,589 | 199,453
Year three | 145,923 | 140,049
Year four | 98,137 | 68,607
Year five | 43,019 | 27,645
More than five years | 133,945 | 206,782
Revolving | 428,398 | 383,082
Revolving-Term | 0 | 0
Total | 1,407,211 | 1,479,749
Commercial | Pass | Commercial construction |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Current fiscal year | 100,774 | 131,235
Year two | 134,440 | 224,794
Year three | 172,508 | 59,649
Year four | 33,903 | 2,420
Year five | 996 | 6,346
More than five years | 4,298 | 4,555
Revolving | 21,714 | 12,778
Revolving-Term | 0 | 0
Total | 468,633 | 441,777
Commercial | Pass | Business banking |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Current fiscal year | 173,154 | 296,254
Year two | 114,831 | 154,335
Year three | 152,423 | 123,207
Year four | 117,529 | 86,552
Year five | 81,934 | 77,238
More than five years | 316,445 | 266,042
Revolving | 103,162 | 103,571
Revolving-Term | 450 | 291
Total | 1,059,928 | 1,107,490
Commercial | Special mention | Commercial real estate |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Current fiscal year | 0 | 0
Year two | 1,368 | 35,499
Year three | 32,780 | 10,200
Year four | 4,422 | 22,502
Year five | 38,966 | 55,174
More than five years | 97,322 | 75,022
Revolving | 0 | 0
Revolving-Term |  | 0
Total | 174,858 | 198,397
Commercial | Special mention | Commercial and industrial |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Current fiscal year | 49 | 3,697
Year two | 2,927 | 8,211
Year three | 1,283 | 2,628
Year four | 3,166 | 697
Year five | 72 | 768
More than five years | 1,934 | 1,046
Revolving | 10,667 | 23,527
Revolving-Term |  | 0
Total | 20,098 | 40,574
Commercial | Special mention | Commercial construction |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Current fiscal year | 0 | 1,578
Year two | 0 | 2,533
Year three | 0 | 3,886
Year four | 0 | 0
Year five | 0 | 0
More than five years | 4,491 | 8,593
Revolving | 0 | 0
Revolving-Term |  | 0
Total | 4,491 | 16,590
Commercial | Special mention | Business banking |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Current fiscal year | 113 | 0
Year two | 153 | 1,060
Year three | 890 | 1,147
Year four | 1,406 | 1,602
Year five | 935 | 1,084
More than five years | 6,265 | 6,866
Revolving | 199 | 637
Revolving-Term | 121 | 123
Total | 10,082 | 12,519
Commercial | Substandard | Commercial real estate |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Current fiscal year | 0 | 0
Year two | 445 | 17,259
Year three | 16,812 | 12,781
Year four | 19,320 | 19,914
Year five | 18,673 | 50,700
More than five years | 123,332 | 83,792
Revolving | 1,500 | 1,500
Revolving-Term |  | 0
Total | 180,082 | 185,946
Commercial | Substandard | Commercial and industrial |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Current fiscal year | 5,196 | 0
Year two | 0 | 7,793
Year three | 19,180 | 2,613
Year four | 1,374 | 8,544
Year five | 5,258 | 75
More than five years | 5,532 | 13,781
Revolving | 5,017 | 2,022
Revolving-Term |  | 0
Total | 41,557 | 34,828
Commercial | Substandard | Commercial construction |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Current fiscal year | 0 | 0
Year two | 2,149 | 3,580
Year three | 7,416 | 0
Year four | 0 | 501
Year five | 0 | 0
More than five years | 3,235 | 3,629
Revolving | 0 | 0
Revolving-Term |  | 0
Total | 12,800 | 7,710
Commercial | Substandard | Business banking |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Current fiscal year | 46 | 103
Year two | 71 | 1,078
Year three | 1,720 | 3,896
Year four | 3,292 | 3,209
Year five | 2,036 | 3,880
More than five years | 21,337 | 25,871
Revolving | 978 | 1,341
Revolving-Term | 635 | 680
Total | 30,115 | 40,058
Commercial | Doubtful | Commercial real estate |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Current fiscal year | 0 | 0
Year two | 0 | 645
Year three | 532 | 0
Year four | 0 | 0
Year five | 0 | 1,989
More than five years | 0 | 6,529
Revolving | 0 | 0
Revolving-Term | 0 | 0
Total | 532 | 9,163
Commercial | Doubtful | Commercial and industrial |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Current fiscal year | 0 | 0
Year two | 0 | 0
Year three | 9,332 | 0
Year four | 0 | 4,401
Year five | 0 | 0
More than five years | 0 | 0
Revolving | 0 | 0
Revolving-Term | 0 | 0
Total | 9,332 | 4,401
Commercial | Doubtful | Commercial construction |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
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 | Doubtful | Business banking |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
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 |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Total | 1,546,123 | 1,552,153
Consumer | Business banking |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Total |  | 303,900
Consumer | Consumer real estate |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Current fiscal year | 89,026 | 120,736
Year two | 107,534 | 122,544
Year three | 94,791 | 69,931
Year four | 60,387 | 65,133
Year five | 44,157 | 76,254
More than five years | 249,283 | 251,047
Revolving | 435,922 | 439,020
Revolving-Term | 24,378 | 22,667
Total | 1,105,478 | 1,167,332
Consumer | Other consumer |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Current fiscal year | 9,833 | 18,864
Year two | 10,904 | 13,162
Year three | 8,575 | 6,784
Year four | 4,002 | 3,395
Year five | 1,810 | 2,082
More than five years | 8,818 | 4,054
Revolving | 50,980 | 27,391
Revolving-Term | 2,660 | 5,153
Total | 97,582 | 80,885
Consumer | Pass | Consumer real estate |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Current fiscal year | 89,026 | 120,736
Year two | 107,534 | 122,171
Year three | 94,583 | 67,700
Year four | 58,622 | 63,653
Year five | 42,789 | 73,805
More than five years | 242,252 | 243,939
Revolving | 435,213 | 438,888
Revolving-Term | 23,088 | 22,667
Total | 1,093,107 | 1,153,559
Consumer | Pass | Other consumer |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Current fiscal year | 9,833 | 18,849
Year two | 10,852 | 13,162
Year three | 8,470 | 6,784
Year four | 3,852 | 3,395
Year five | 1,442 | 2,082
More than five years | 2,888 | 687
Revolving | 50,725 | 26,647
Revolving-Term | 1,113 | 2,767
Total | 89,175 | 74,373
Consumer | Special mention | Consumer real estate |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Current fiscal year | 0 | 0
Year two | 0 | 0
Year three | 0 | 1,489
Year four | 0 | 0
Year five | 0 | 0
More than five years | 2,163 | 150
Revolving | 0 | 132
Revolving-Term |  | 0
Total | 2,163 | 1,771
Consumer | Special mention | Other consumer |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
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 | Substandard | Consumer real estate |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Current fiscal year | 0 | 0
Year two | 0 | 373
Year three | 208 | 742
Year four | 1,765 | 1,480
Year five | 1,368 | 2,449
More than five years | 4,868 | 6,958
Revolving | 709 | 0
Revolving-Term | 1,290 | 0
Total | 10,208 | 12,002
Consumer | Substandard | Other consumer |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
Current fiscal year | 0 | 15
Year two | 52 | 0
Year three | 105 | 0
Year four | 150 | 0
Year five | 368 | 0
More than five years | 5,930 | 3,367
Revolving | 255 | 744
Revolving-Term | 1,547 | 2,386
Total | 8,407 | 6,512
Consumer | Doubtful | Consumer real estate |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
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 | Doubtful | Other consumer |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |
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

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