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Allowance for Loan Losses - Age Analysis of Past Due Loans Segregated by Class of Loans (Details) - USD ($) $ in Thousands | Mar. 31, 2019 | Dec. 31, 2018
--- | --- | ---
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |
Current | $ 5,878,384 | $ 5,890,141
Past due | 59,774 | 58,878
Non - performing | 47,950 | 46,073
Total Loans | 5,938,158 | 5,949,019
Commercial real estate |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |
Current | 2,868,403 | 2,903,997
Past due | 33,222 | 17,835
Non - performing | 29,109 | 12,052
Total Loans | 2,901,625 | 2,921,832
Commercial and industrial |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |
Current | 1,504,824 | 1,482,473
Past due | 8,183 | 10,943
Non - performing | 6,810 | 8,960
Total Loans | 1,513,007 | 1,493,416
Commercial construction |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |
Current | 244,432 | 243,004
Past due | 1,226 | 14,193
Non - performing | 1,226 | 14,193
Total Loans | 245,658 | 257,197
Residential mortgage |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |
Current | 719,422 | 717,447
Past due | 10,492 | 9,232
Non - performing | 6,630 | 7,128
Total Loans | 729,914 | 726,679
Home equity |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |
Current | 457,452 | 465,152
Past due | 6,114 | 6,410
Non - performing | 4,146 | 3,698
Total Loans | 463,566 | 471,562
Installment and other consumer |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |
Current | 70,645 | 67,281
Past due | 315 | 265
Non - performing | 29 | 42
Total Loans | 70,960 | 67,546
Consumer construction |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |
Current | 10,500 | 8,416
Past due | 222 | 0
Non - performing | 0 | 0
Total Loans | 10,722 | 8,416
Loans Held for Sale |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |
Current | 2,706 | 2,371
Past due | 0 | 0
Non - performing | 0 | 0
Total Loans | 2,706 | 2,371
30 to 59 Days Past Due |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |
Past due | 8,519 | 8,473
30 to 59 Days Past Due | Commercial real estate |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |
Past due | 1,876 | 3,638
30 to 59 Days Past Due | Commercial and industrial |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |
Past due | 785 | 1,000
30 to 59 Days Past Due | Commercial construction |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |
Past due | 0 |
30 to 59 Days Past Due | Residential mortgage |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |
Past due | 3,695 | 1,584
30 to 59 Days Past Due | Home equity |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |
Past due | 1,714 | 2,103
30 to 59 Days Past Due | Installment and other consumer |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |
Past due | 227 | 148
30 to 59 Days Past Due | Consumer construction |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |
Past due | 222 | 0
30 to 59 Days Past Due | Loans Held for Sale |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |
Past due | 0 | 0
60 to 89 Days Past Due |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |
Past due | 3,305 | 4,332
60 to 89 Days Past Due | Commercial real estate |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |
Past due | 2,237 | 2,145
60 to 89 Days Past Due | Commercial and industrial |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |
Past due | 588 | 983
60 to 89 Days Past Due | Commercial construction |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |
Past due | 0 | 0
60 to 89 Days Past Due | Residential mortgage |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |
Past due | 167 | 520
60 to 89 Days Past Due | Home equity |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |
Past due | 254 | 609
60 to 89 Days Past Due | Installment and other consumer |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |
Past due | 59 | 75
60 to 89 Days Past Due | Consumer construction |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |
Past due | 0 | 0
60 to 89 Days Past Due | Loans Held for Sale |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |
Past due | $ 0 | $ 0

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