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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, 2020 | Jan. 01, 2020 | Dec. 31, 2019
--- | --- | --- | ---
Financing Receivable, Credit Quality Indicator [Line Items] |  |  |
2020 | $ 1,268,757 |  |
2019 | 1,240,238 |  |
2018 | 915,402 |  |
2017 | 612,707 |  |
2016 | 654,916 |  |
2015 and Prior | 1,657,854 |  |
Revolving | 1,018,345 |  |
Revolving-Term | 26,649 |  |
Total | 7,394,868 |  | $ 7,137,152
Commercial |  |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |  |
Total | 5,810,034 |  | 5,512,796
Commercial | Commercial real estate |  |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |  |
2020 | 277,760 |  |
2019 | 462,569 |  |
2018 | 454,551 |  |
2017 | 326,132 |  |
2016 | 425,755 |  |
2015 and Prior | 821,346 |  |
Revolving | 50,114 |  |
Revolving-Term | 0 |  |
Total | 2,818,227 | $ 3,416,518 | 3,059,592
Commercial | Commercial and industrial |  |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |  |
2020 | 686,461 |  |
2019 | 234,748 |  |
2018 | 156,217 |  |
2017 | 94,327 |  |
2016 | 47,706 |  |
2015 and Prior | 218,559 |  |
Revolving | 380,631 |  |
Revolving-Term | 0 |  |
Total | 1,818,649 | 1,720,833 | 1,480,529
Commercial | Consumer construction |  |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |  |
2020 | 102,950 |  |
2019 | 227,000 |  |
2018 | 83,556 |  |
2017 | 17,596 |  |
2016 | 9,854 |  |
2015 and Prior | 18,686 |  |
Revolving | 11,218 |  |
Revolving-Term | 0 |  |
Total | 470,860 | 375,445 | 370,060
Commercial | Business banking |  |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |  |
2020 | 97,471 |  |
2019 | 164,039 |  |
2018 | 137,941 |  |
2017 | 99,360 |  |
2016 | 86,333 |  |
2015 and Prior | 323,499 |  |
Revolving | 106,166 |  |
Revolving-Term | 1,142 |  |
Total | 1,015,951 | 0 | 846,790
Commercial | Pass |  |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |  |
Total |  |  | 5,254,056
Commercial | Pass | Commercial real estate |  |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |  |
2020 | 277,760 |  |
2019 | 406,883 |  |
2018 | 446,299 |  |
2017 | 289,243 |  |
2016 | 326,634 |  |
2015 and Prior | 644,888 |  |
Revolving | 47,764 |  |
Revolving-Term | 0 |  |
Total | 2,439,471 |  |
Commercial | Pass | Commercial and industrial |  |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |  |
2020 | 682,632 |  |
2019 | 209,253 |  |
2018 | 149,912 |  |
2017 | 76,118 |  |
2016 | 38,877 |  |
2015 and Prior | 199,772 |  |
Revolving | 347,762 |  |
Revolving-Term | 0 |  |
Total | 1,704,326 |  |
Commercial | Pass | Consumer construction |  |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |  |
2020 | 102,950 |  |
2019 | 223,433 |  |
2018 | 79,733 |  |
2017 | 15,844 |  |
2016 | 9,854 |  |
2015 and Prior | 9,915 |  |
Revolving | 11,127 |  |
Revolving-Term | 0 |  |
Total | 452,856 |  |
Commercial | Pass | Business banking |  |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |  |
2020 | 97,367 |  |
2019 | 163,334 |  |
2018 | 133,688 |  |
2017 | 93,886 |  |
2016 | 81,481 |  |
2015 and Prior | 289,927 |  |
Revolving | 104,721 |  |
Revolving-Term | 336 |  |
Total | 964,740 |  |
Commercial | Special mention |  |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |  |
Total |  |  | 103,878
Commercial | Special mention | Commercial real estate |  |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |  |
2020 | 0 |  |
2019 | 37,197 |  |
2018 | 186 |  |
2017 | 21,850 |  |
2016 | 43,805 |  |
2015 and Prior | 64,855 |  |
Revolving | 850 |  |
Revolving-Term | 0 |  |
Total | 168,743 |  |
Commercial | Special mention | Commercial and industrial |  |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |  |
2020 | 3,829 |  |
2019 | 20,396 |  |
2018 | 3,613 |  |
2017 | 968 |  |
2016 | 8,563 |  |
2015 and Prior | 6,998 |  |
Revolving | 30,552 |  |
Revolving-Term | 0 |  |
Total | 74,919 |  |
Commercial | Special mention | Consumer construction |  |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |  |
2020 | 0 |  |
2019 | 0 |  |
2018 | 3,823 |  |
2017 | 0 |  |
2016 | 0 |  |
2015 and Prior | 5,033 |  |
Revolving | 91 |  |
Revolving-Term | 0 |  |
Total | 8,947 |  |
Commercial | Special mention | Business banking |  |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |  |
2020 | 0 |  |
2019 | 59 |  |
2018 | 1,049 |  |
2017 | 1,719 |  |
2016 | 1,093 |  |
2015 and Prior | 7,055 |  |
Revolving | 691 |  |
Revolving-Term | 123 |  |
Total | 11,789 |  |
Commercial | Substandard |  |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |  |
Total |  |  | 152,651
Commercial | Substandard | Commercial real estate |  |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |  |
2020 | 0 |  |
2019 | 18,489 |  |
2018 | 8,066 |  |
2017 | 15,039 |  |
2016 | 54,975 |  |
2015 and Prior | 105,474 |  |
Revolving | 1,500 |  |
Revolving-Term | 0 |  |
Total | 203,543 |  |
Commercial | Substandard | Commercial and industrial |  |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |  |
2020 | 0 |  |
2019 | 4,861 |  |
2018 | 2,519 |  |
2017 | 14,704 |  |
2016 | 71 |  |
2015 and Prior | 11,789 |  |
Revolving | 2,317 |  |
Revolving-Term | 0 |  |
Total | 36,261 |  |
Commercial | Substandard | Consumer construction |  |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |  |
2020 | 0 |  |
2019 | 3,567 |  |
2018 | 0 |  |
2017 | 1,752 |  |
2016 | 0 |  |
2015 and Prior | 3,738 |  |
Revolving | 0 |  |
Revolving-Term | 0 |  |
Total | 9,057 |  |
Commercial | Substandard | Business banking |  |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |  |
2020 | 104 |  |
2019 | 646 |  |
2018 | 3,204 |  |
2017 | 3,755 |  |
2016 | 3,759 |  |
2015 and Prior | 26,517 |  |
Revolving | 754 |  |
Revolving-Term | 683 |  |
Total | 39,422 |  |
Commercial | Doubtful |  |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |  |
Total |  |  | 2,211
Commercial | Doubtful | Commercial real estate |  |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |  |
2020 | 0 |  |
2019 | 0 |  |
2018 | 0 |  |
2017 | 0 |  |
2016 | 341 |  |
2015 and Prior | 6,129 |  |
Revolving | 0 |  |
Revolving-Term | 0 |  |
Total | 6,470 |  |
Commercial | Doubtful | Commercial and industrial |  |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |  |
2020 | 0 |  |
2019 | 238 |  |
2018 | 173 |  |
2017 | 2,537 |  |
2016 | 195 |  |
2015 and Prior | 0 |  |
Revolving | 0 |  |
Revolving-Term | 0 |  |
Total | 3,143 |  |
Commercial | Doubtful | Consumer construction |  |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |  |
2020 | 0 |  |
2019 | 0 |  |
2018 | 0 |  |
2017 | 0 |  |
2016 | 0 |  |
2015 and Prior | 0 |  |
Revolving | 0 |  |
Revolving-Term | 0 |  |
Total | 0 |  |
Commercial | Doubtful | Business banking |  |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |  |
2020 | 0 |  |
2019 | 0 |  |
2018 | 0 |  |
2017 | 0 |  |
2016 | 0 |  |
2015 and Prior | 0 |  |
Revolving | 0 |  |
Revolving-Term | 0 |  |
Total | 0 |  |
Consumer |  |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |  |
Total | 1,584,834 |  | 1,624,356
Consumer | Consumer construction |  |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |  |
Total | 15,343 |  | 8,390
Consumer | Consumer real estate |  |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |  |
2020 | 95,412 |  |
2019 | 136,323 |  |
2018 | 75,055 |  |
2017 | 70,907 |  |
2016 | 81,618 |  |
2015 and Prior | 271,042 |  |
Revolving | 436,604 |  |
Revolving-Term | 23,519 |  |
Total | 1,190,480 | 1,545,323 | 1,295,207
Consumer | Other consumer |  |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |  |
2020 | 8,703 |  |
2019 | 15,559 |  |
2018 | 8,082 |  |
2017 | 4,385 |  |
2016 | 3,650 |  |
2015 and Prior | 4,722 |  |
Revolving | 33,612 |  |
Revolving-Term | 1,988 |  |
Total | 80,701 | $ 79,033 | $ 84,974
Consumer | Pass | Consumer real estate |  |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |  |
2020 | 95,412 |  |
2019 | 136,136 |  |
2018 | 74,500 |  |
2017 | 70,027 |  |
2016 | 79,784 |  |
2015 and Prior | 263,696 |  |
Revolving | 436,392 |  |
Revolving-Term | 22,546 |  |
Total | 1,178,493 |  |
Consumer | Pass | Other consumer |  |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |  |
2020 | 8,703 |  |
2019 | 15,078 |  |
2018 | 7,953 |  |
2017 | 4,270 |  |
2016 | 3,039 |  |
2015 and Prior | 854 |  |
Revolving | 33,216 |  |
Revolving-Term | 641 |  |
Total | 73,754 |  |
Consumer | Special mention | Consumer real estate |  |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |  |
2020 | 0 |  |
2019 | 0 |  |
2018 | 0 |  |
2017 | 0 |  |
2016 | 798 |  |
2015 and Prior | 153 |  |
Revolving | 0 |  |
Revolving-Term | 0 |  |
Total | 951 |  |
Consumer | Special mention | Other consumer |  |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |  |
2020 | 0 |  |
2019 | 0 |  |
2018 | 0 |  |
2017 | 0 |  |
2016 | 0 |  |
2015 and Prior | 0 |  |
Revolving | 0 |  |
Revolving-Term | 0 |  |
Total | 0 |  |
Consumer | Substandard | Consumer real estate |  |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |  |
2020 | 0 |  |
2019 | 187 |  |
2018 | 555 |  |
2017 | 880 |  |
2016 | 1,036 |  |
2015 and Prior | 7,193 |  |
Revolving | 212 |  |
Revolving-Term | 973 |  |
Total | 11,036 |  |
Consumer | Substandard | Other consumer |  |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |  |
2020 | 0 |  |
2019 | 481 |  |
2018 | 129 |  |
2017 | 115 |  |
2016 | 611 |  |
2015 and Prior | 3,868 |  |
Revolving | 396 |  |
Revolving-Term | 1,347 |  |
Total | 6,947 |  |
Consumer | Doubtful | Consumer real estate |  |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |  |
2020 | 0 |  |
2019 | 0 |  |
2018 | 0 |  |
2017 | 0 |  |
2016 | 0 |  |
2015 and Prior | 0 |  |
Revolving | 0 |  |
Revolving-Term | 0 |  |
Total | 0 |  |
Consumer | Doubtful | Other consumer |  |  |
Financing Receivable, Credit Quality Indicator [Line Items] |  |  |
2020 | 0 |  |
2019 | 0 |  |
2018 | 0 |  |
2017 | 0 |  |
2016 | 0 |  |
2015 and Prior | 0 |  |
Revolving | 0 |  |
Revolving-Term | 0 |  |
Total | $ 0 |  |

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