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Allowance for Credit Losses - Age Analysis of Past Due Loans Segregated by Class of Loans (Details) $ in Thousands | 3 Months Ended | 6 Months Ended |  |
--- | --- | --- | --- | ---
Jun. 30, 2020 USD ($) loan | Jun. 30, 2019 USD ($) loan | Jun. 30, 2020 USD ($) loan | Jun. 30, 2019 USD ($) loan | Jan. 01, 2020 USD ($) | Dec. 31, 2019 USD ($)
Financing Receivable, Past Due [Line Items] |  |  |  |  |  |  |  |  |  |
Current |  | $ 7,446,796 | [1] |  | $ 7,446,796 | [1] |  |  | $ 7,055,361 |
Past due |  | 101,762 | [1] |  | 101,762 | [1] |  |  | 81,791 |
Non - performing |  | 90,113 | [1] |  | 90,113 | [1] |  |  | 54,057 |
Total |  | $ 7,548,558 | [1] |  | $ 7,548,558 | [1] |  |  | 7,137,152 |
Number of loans | loan | [2] | 11 |  | 14 | 20 |  | 25 |  |  |
Restructured loans | [2],[3] | $ 1,304 |  | $ 6,427 | $ 7,853 |  | $ 11,248 |  |  |
Commercial real estate |  |  |  |  |  |  |  |  |  |
Financing Receivable, Past Due [Line Items] |  |  |  |  |  |  |  |  |  |
Number of loans | loan |  | 0 |  | 3 | 1 |  | 3 |  |  |
Restructured loans | [3] | $ 0 |  | $ 6,090 | $ 2,210 |  | $ 6,090 |  |  |
Commercial and industrial |  |  |  |  |  |  |  |  |  |
Financing Receivable, Past Due [Line Items] |  |  |  |  |  |  |  |  |  |
Number of loans | loan |  | 2 |  | 0 | 3 |  | 1 |  |  |
Restructured loans | [3] | $ 102 |  | $ 0 | $ 2,170 |  | $ 4,529 |  |  |
Commercial construction |  |  |  |  |  |  |  |  |  |
Financing Receivable, Past Due [Line Items] |  |  |  |  |  |  |  |  |  |
Number of loans | loan |  | 2 |  | 0 | 3 |  | 0 |  |  |
Restructured loans | [3] | $ 701 |  | $ 0 | $ 2,572 |  | $ 0 |  |  |
CARES Act, Paycheck Protection Program Loans |  |  |  |  |  |  |  |  |  |
Financing Receivable, Past Due [Line Items] |  |  |  |  |  |  |  |  |  |
Number of loans | loan |  |  |  |  | 2,360 |  |  |  |  |
Restructured loans |  |  |  |  | $ 1,400,000 |  |  |  |  |
30 to 59 Days Past Due |  |  |  |  |  |  |  |  |  |
Financing Receivable, Past Due [Line Items] |  |  |  |  |  |  |  |  |  |
Past due |  | 2,469 | [1] |  | 2,469 | [1] |  |  | 17,992 |
60 to 89 Days Past Due |  |  |  |  |  |  |  |  |  |
Financing Receivable, Past Due [Line Items] |  |  |  |  |  |  |  |  |  |
Past due |  | 6,980 | [1] |  | 6,980 | [1] |  |  | 5,985 |
90 Days Past Due |  |  |  |  |  |  |  |  |  |
Financing Receivable, Past Due [Line Items] |  |  |  |  |  |  |  |  |  |
Past due |  | 2,200 | [1],[4] |  | 2,200 | [1],[4] |  |  | 3,757 | [5]
Commercial | Commercial real estate |  |  |  |  |  |  |  |  |  |
Financing Receivable, Past Due [Line Items] |  |  |  |  |  |  |  |  |  |
Current |  | 2,806,327 | [1] |  | 2,806,327 | [1] |  |  | 3,025,505 |
Past due |  | 55,776 | [1] |  | 55,776 | [1] |  |  | 34,087 |
Non - performing |  | 55,776 | [1] |  | 55,776 | [1] |  |  | 25,356 |
Total |  | 2,862,103 | [1] |  | 2,862,103 | [1] |  | $ 3,416,518 | 3,059,592 |
Commercial | Commercial and industrial |  |  |  |  |  |  |  |  |  |
Financing Receivable, Past Due [Line Items] |  |  |  |  |  |  |  |  |  |
Current |  | 1,678,314 | [1] |  | 1,678,314 | [1] |  |  | 1,466,460 |
Past due |  | 4,362 | [1] |  | 4,362 | [1] |  |  | 14,069 |
Non - performing |  | 2,626 | [1] |  | 2,626 | [1] |  |  | 10,911 |
Total |  | 1,682,676 | [1] |  | 1,682,676 | [1] |  | 1,720,833 | 1,480,529 |
Commercial | Commercial construction |  |  |  |  |  |  |  |  |  |
Financing Receivable, Past Due [Line Items] |  |  |  |  |  |  |  |  |  |
Current |  | 451,594 | [1] |  | 451,594 | [1] |  |  | 367,204 |
Past due |  | 1,504 | [1] |  | 1,504 | [1] |  |  | 2,856 |
Non - performing |  | 1,504 | [1] |  | 1,504 | [1] |  |  | 737 |
Total |  | 453,098 | [1] |  | 453,098 | [1] |  | 375,445 | 370,060 |
Commercial | Business banking |  |  |  |  |  |  |  |  |  |
Financing Receivable, Past Due [Line Items] |  |  |  |  |  |  |  |  |  |
Current |  | 1,248,611 | [1] |  | 1,248,611 | [1] |  |  | 830,735 |
Past due |  | 20,224 | [1] |  | 20,224 | [1] |  |  | 16,055 |
Non - performing |  | 16,475 | [1] |  | 16,475 | [1] |  |  | 9,863 |
Total |  | 1,268,835 | [1] |  | 1,268,835 | [1] |  | 0 | 846,790 |
Commercial | 30 to 59 Days Past Due | Commercial real estate |  |  |  |  |  |  |  |  |  |
Financing Receivable, Past Due [Line Items] |  |  |  |  |  |  |  |  |  |
Past due |  | 0 | [1] |  | 0 | [1] |  |  | 7,749 |
Commercial | 30 to 59 Days Past Due | Commercial and industrial |  |  |  |  |  |  |  |  |  |
Financing Receivable, Past Due [Line Items] |  |  |  |  |  |  |  |  |  |
Past due |  | 0 | [1] |  | 0 | [1] |  |  | 126 |
Commercial | 30 to 59 Days Past Due | Commercial construction |  |  |  |  |  |  |  |  |  |
Financing Receivable, Past Due [Line Items] |  |  |  |  |  |  |  |  |  |
Past due |  | 0 | [1] |  | 0 | [1] |  |  | 956 |
Commercial | 30 to 59 Days Past Due | Business banking |  |  |  |  |  |  |  |  |  |
Financing Receivable, Past Due [Line Items] |  |  |  |  |  |  |  |  |  |
Past due |  | 839 | [1] |  | 839 | [1] |  |  | 5,093 |
Commercial | 60 to 89 Days Past Due | Commercial real estate |  |  |  |  |  |  |  |  |  |
Financing Receivable, Past Due [Line Items] |  |  |  |  |  |  |  |  |  |
Past due |  | 0 | [1] |  | 0 | [1] |  |  | 71 |
Commercial | 60 to 89 Days Past Due | Commercial and industrial |  |  |  |  |  |  |  |  |  |
Financing Receivable, Past Due [Line Items] |  |  |  |  |  |  |  |  |  |
Past due |  | 230 | [1] |  | 230 | [1] |  |  | 1,589 |
Commercial | 60 to 89 Days Past Due | Commercial construction |  |  |  |  |  |  |  |  |  |
Financing Receivable, Past Due [Line Items] |  |  |  |  |  |  |  |  |  |
Past due |  | 0 | [1] |  | 0 | [1] |  |  | 1,163 |
Commercial | 60 to 89 Days Past Due | Business banking |  |  |  |  |  |  |  |  |  |
Financing Receivable, Past Due [Line Items] |  |  |  |  |  |  |  |  |  |
Past due |  | 2,910 | [1] |  | 2,910 | [1] |  |  | 1,099 |
Commercial | 90 Days Past Due | Commercial real estate |  |  |  |  |  |  |  |  |  |
Financing Receivable, Past Due [Line Items] |  |  |  |  |  |  |  |  |  |
Past due |  | 0 | [1],[4] |  | 0 | [1],[4] |  |  | 911 | [5]
Commercial | 90 Days Past Due | Commercial and industrial |  |  |  |  |  |  |  |  |  |
Financing Receivable, Past Due [Line Items] |  |  |  |  |  |  |  |  |  |
Past due |  | 1,506 | [1],[4] |  | 1,506 | [1],[4] |  |  | 1,443 | [5]
Commercial | 90 Days Past Due | Commercial construction |  |  |  |  |  |  |  |  |  |
Financing Receivable, Past Due [Line Items] |  |  |  |  |  |  |  |  |  |
Past due | [5] |  |  |  |  |  |  |  | 0 |
Commercial | 90 Days Past Due | Business banking |  |  |  |  |  |  |  |  |  |
Financing Receivable, Past Due [Line Items] |  |  |  |  |  |  |  |  |  |
Past due |  | 0 | [1],[4] |  | 0 | [1],[4] |  |  | 0 | [5]
Consumer | Consumer real estate |  |  |  |  |  |  |  |  |  |
Financing Receivable, Past Due [Line Items] |  |  |  |  |  |  |  |  |  |
Current |  | 1,184,530 | [1] |  | 1,184,530 | [1] |  |  | 1,283,591 |
Past due |  | 17,583 | [1] |  | 17,583 | [1] |  |  | 11,616 |
Non - performing |  | 11,873 | [1] |  | 11,873 | [1] |  |  | 6,063 |
Total |  | 1,202,113 | [1] |  | 1,202,113 | [1] |  | 1,545,323 | 1,295,207 |
Consumer | Other consumer |  |  |  |  |  |  |  |  |  |
Financing Receivable, Past Due [Line Items] |  |  |  |  |  |  |  |  |  |
Current |  | 77,420 | [1] |  | 77,420 | [1] |  |  | 81,866 |
Past due |  | 2,313 | [1] |  | 2,313 | [1] |  |  | 3,108 |
Non - performing |  | 1,859 | [1] |  | 1,859 | [1] |  |  | 1,127 |
Total |  | 79,733 | [1] |  | 79,733 | [1] |  | $ 79,033 | 84,974 |
Consumer | 30 to 59 Days Past Due | Consumer real estate |  |  |  |  |  |  |  |  |  |
Financing Receivable, Past Due [Line Items] |  |  |  |  |  |  |  |  |  |
Past due |  | 1,429 | [1] |  | 1,429 | [1] |  |  | 2,620 |
Consumer | 30 to 59 Days Past Due | Other consumer |  |  |  |  |  |  |  |  |  |
Financing Receivable, Past Due [Line Items] |  |  |  |  |  |  |  |  |  |
Past due |  | 201 | [1] |  | 201 | [1] |  |  | 1,448 |
Consumer | 60 to 89 Days Past Due | Consumer real estate |  |  |  |  |  |  |  |  |  |
Financing Receivable, Past Due [Line Items] |  |  |  |  |  |  |  |  |  |
Past due |  | 3,709 | [1] |  | 3,709 | [1] |  |  | 1,758 |
Consumer | 60 to 89 Days Past Due | Other consumer |  |  |  |  |  |  |  |  |  |
Financing Receivable, Past Due [Line Items] |  |  |  |  |  |  |  |  |  |
Past due |  | 131 | [1] |  | 131 | [1] |  |  | 305 |
Consumer | 90 Days Past Due | Consumer real estate |  |  |  |  |  |  |  |  |  |
Financing Receivable, Past Due [Line Items] |  |  |  |  |  |  |  |  |  |
Past due |  | 572 | [1],[4] |  | 572 | [1],[4] |  |  | 1,175 | [5]
Consumer | 90 Days Past Due | Other consumer |  |  |  |  |  |  |  |  |  |
Financing Receivable, Past Due [Line Items] |  |  |  |  |  |  |  |  |  |
Past due |  | $ 122 | [1],[4] |  | $ 122 | [1],[4] |  |  | $ 228 | [5]
[1] | We had 2,360 loans that were modified totaling $1.4 billion under the CARES Act at June 30, 2020. These customers were not considered past due as a result of their delayed payments. Upon exiting the loan modification deferral program, the measurement of loan delinquency will resume where it left off upon entry into the program. Due to the modification program, this delinquency table may not accurately reflect the credit risk associated with these loans.
[2] | Refer to Note 1, Basis of Presentation for details of reclassification of our portfolio segments related to the adoption of ASU 2016-13 Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instrument.
[3] | Excludes loans that were fully paid off or fully charged-off by period end. The pre-modification balance represents the balance outstanding prior to modification. The post-modification balance represents the outstanding balance at period end.
[4] | Represents acquired loans that were recorded at fair value at the acquisition date and remain performing at June 30, 2020.
[5] | Represents acquired loans that were recorded at fair value at the acquisition date and remain performing at December 31, 2019.

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