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Allowance for Loan Losses - Age Analysis of Past Due Loans Segregated by Class of Loans (Details) - USD ($) $ in Thousands | Dec. 31, 2016 | Dec. 31, 2015
--- | --- | ---
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |
Loans, Current | $ 5,563,123 | $ 5,002,925
Loans, Past Due | 52,089 | 60,008
Non-performing loans | 42,635 | 35,382
Total Loans | 5,615,212 | 5,062,933
Commercial Real Estate |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |
Loans, Current | 2,479,513 | 2,145,655
Loans, Past Due | 18,963 | 20,948
Non-performing loans | 16,172 | 8,719
Total Loans | 2,498,476 | 2,166,603
Commercial and Industrial |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |
Loans, Current | 1,391,475 | 1,244,802
Loans, Past Due | 9,560 | 12,028
Non-performing loans | 8,071 | 9,279
Total Loans | 1,401,035 | 1,256,830
Commercial Construction |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |
Loans, Current | 450,410 | 401,084
Loans, Past Due | 5,474 | 12,360
Non-performing loans | 4,927 | 8,753
Total Loans | 455,884 | 413,444
Residential Mortgage |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |
Loans, Current | 689,635 | 631,085
Loans, Past Due | 12,347 | 8,287
Non-performing loans | 9,918 | 5,629
Total Loans | 701,982 | 639,372
Home Equity |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |
Loans, Current | 476,866 | 465,055
Loans, Past Due | 5,418 | 5,790
Non-performing loans | 3,439 | 2,902
Total Loans | 482,284 | 470,845
Installment and Other Consumer |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |
Loans, Current | 65,525 | 73,486
Loans, Past Due | 327 | 453
Non-performing loans | 108 | 100
Total Loans | 65,852 | 73,939
Consumer Construction |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |
Loans, Current | 5,906 | 6,579
Loans, Past Due | 0 | 0
Non-performing loans | 0 | 0
Total Loans | 5,906 | 6,579
Loans Held for Sale |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |
Loans, Current | 3,793 | 35,179
Loans, Past Due | 0 | 142
Non-performing loans | 0 | 0
Total Loans | 3,793 | 35,321
30-59 Days Past Due |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |
Loans, Past Due | 6,598 | 22,001
30-59 Days Past Due | Commercial Real Estate |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |
Loans, Past Due | 2,032 | 11,602
30-59 Days Past Due | Commercial and Industrial |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |
Loans, Past Due | 1,061 | 2,453
30-59 Days Past Due | Commercial Construction |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |
Loans, Past Due | 547 | 3,517
30-59 Days Past Due | Residential Mortgage |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |
Loans, Past Due | 1,312 | 1,728
30-59 Days Past Due | Home Equity |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |
Loans, Past Due | 1,470 | 2,365
30-59 Days Past Due | Installment and Other Consumer |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |
Loans, Past Due | 176 | 242
30-59 Days Past Due | Consumer Construction |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |
Loans, Past Due | 0 | 0
30-59 Days Past Due | Loans Held for Sale |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |
Loans, Past Due | 0 | 94
60-89 Days Past Due |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |
Loans, Past Due | 2,856 | 2,625
60-89 Days Past Due | Commercial Real Estate |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |
Loans, Past Due | 759 | 627
60-89 Days Past Due | Commercial and Industrial |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |
Loans, Past Due | 428 | 296
60-89 Days Past Due | Commercial Construction |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |
Loans, Past Due | 0 | 90
60-89 Days Past Due | Residential Mortgage |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |
Loans, Past Due | 1,117 | 930
60-89 Days Past Due | Home Equity |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |
Loans, Past Due | 509 | 523
60-89 Days Past Due | Installment and Other Consumer |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |
Loans, Past Due | 43 | 111
60-89 Days Past Due | Consumer Construction |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |
Loans, Past Due | 0 | 0
60-89 Days Past Due | Loans Held for Sale |  |
Financing Receivable, Recorded Investment, Past Due [Line Items] |  |
Loans, Past Due | $ 0 | $ 48

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