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Loans and Loans Held for Sale - Summary of Restructured Loans (Detail) $ in Thousands | 3 Months Ended | 9 Months Ended | 12 Months Ended
--- | --- | --- | ---
Sep. 30, 2016 USD ($) tdr | Sep. 30, 2015 USD ($) tdr | Sep. 30, 2016 USD ($) tdr | Sep. 30, 2015 USD ($) tdr | Dec. 31, 2015 USD ($)
Receivables [Abstract] |  |  |  |  |  |
Loans Receivable Held-for-sale, Reconciliation to Cash Flow, Period Increase (Decrease) |  |  |  | $ 23,600 |  |
Gain on sale of credit card portfolio |  | $ 0 | $ 0 | $ 2,066 | $ 0 |
Financing Receivable, Modifications [Line Items] |  |  |  |  |  |
Threshold period of satisfactory performance for troubled debt restructuring to be restored to accruing status |  |  |  | 6 months |  |
Restructured loans | [1] | $ 5,003 | $ 1,578 | $ 15,775 | $ 5,353 |
Number of troubled debt restructuring loans returned back to accruing status | tdr |  | 0 | 6 | 0 | 6 |
Amount of troubled debt restructuring loans returned back to accruing status |  |  | $ 300 |  | $ 300 |
Installment and Other Consumer |  |  |  |  |  |
Receivables [Abstract] |  |  |  |  |  |
Loans Receivable Held-for-sale, Reconciliation to Cash Flow, Period Increase (Decrease) |  |  |  | $ 25,000 |  |
Gain on sale of credit card portfolio |  |  |  | 2,100 |  |
Financing Receivable |  |  |  |  |  |
Financing Receivable, Modifications [Line Items] |  |  |  |  |  |
Restructured loans |  |  |  | 28,031 |  | $ 31,614
Financing Receivable | Commercial and Industrial |  |  |  |  |  |
Financing Receivable, Modifications [Line Items] |  |  |  |  |  |
Restructured loans |  |  |  | 7,870 |  | 7,891
Financing Receivable | Commercial Real Estate |  |  |  |  |  |
Financing Receivable, Modifications [Line Items] |  |  |  |  |  |
Restructured loans |  |  |  | 3,920 |  | 10,370
Financing Receivable | Commercial Construction |  |  |  |  |  |
Financing Receivable, Modifications [Line Items] |  |  |  |  |  |
Restructured loans |  |  |  | 4,452 |  | 6,278
Financing Receivable | Residential Mortgage |  |  |  |  |  |
Financing Receivable, Modifications [Line Items] |  |  |  |  |  |
Restructured loans |  |  |  | 7,701 |  | 3,255
Financing Receivable | Home Equity |  |  |  |  |  |
Financing Receivable, Modifications [Line Items] |  |  |  |  |  |
Restructured loans |  |  |  | 4,057 |  | 3,707
Financing Receivable | Installment and Other Consumer |  |  |  |  |  |
Financing Receivable, Modifications [Line Items] |  |  |  |  |  |
Restructured loans |  |  |  | 31 |  | 113
Performing Financial Instruments |  |  |  |  |  |
Financing Receivable, Modifications [Line Items] |  |  |  |  |  |
Restructured loans |  |  |  | 12,936 |  | 23,955
Performing Financial Instruments | Commercial and Industrial |  |  |  |  |  |
Financing Receivable, Modifications [Line Items] |  |  |  |  |  |
Restructured loans |  |  |  | 863 |  | 6,321
Performing Financial Instruments | Commercial Real Estate |  |  |  |  |  |
Financing Receivable, Modifications [Line Items] |  |  |  |  |  |
Restructured loans |  |  |  | 3,054 |  | 6,822
Performing Financial Instruments | Commercial Construction |  |  |  |  |  |
Financing Receivable, Modifications [Line Items] |  |  |  |  |  |
Restructured loans |  |  |  | 3,460 |  | 5,013
Performing Financial Instruments | Residential Mortgage |  |  |  |  |  |
Financing Receivable, Modifications [Line Items] |  |  |  |  |  |
Restructured loans |  |  |  | 2,453 |  | 2,590
Performing Financial Instruments | Home Equity |  |  |  |  |  |
Financing Receivable, Modifications [Line Items] |  |  |  |  |  |
Restructured loans |  |  |  | 3,084 |  | 3,184
Performing Financial Instruments | Installment and Other Consumer |  |  |  |  |  |
Financing Receivable, Modifications [Line Items] |  |  |  |  |  |
Restructured loans |  |  |  | 22 |  | 25
Nonperforming Financial Instruments |  |  |  |  |  |
Financing Receivable, Modifications [Line Items] |  |  |  |  |  |
Restructured loans |  |  |  | 15,095 |  | 7,659
Nonperforming Financial Instruments | Commercial and Industrial |  |  |  |  |  |
Financing Receivable, Modifications [Line Items] |  |  |  |  |  |
Restructured loans |  |  |  | 7,007 |  | 1,570
Nonperforming Financial Instruments | Commercial Real Estate |  |  |  |  |  |
Financing Receivable, Modifications [Line Items] |  |  |  |  |  |
Restructured loans |  |  |  | 866 |  | 3,548
Nonperforming Financial Instruments | Commercial Construction |  |  |  |  |  |
Financing Receivable, Modifications [Line Items] |  |  |  |  |  |
Restructured loans |  |  |  | 992 |  | 1,265
Nonperforming Financial Instruments | Residential Mortgage |  |  |  |  |  |
Financing Receivable, Modifications [Line Items] |  |  |  |  |  |
Restructured loans |  |  |  | 5,248 |  | 665
Nonperforming Financial Instruments | Home Equity |  |  |  |  |  |
Financing Receivable, Modifications [Line Items] |  |  |  |  |  |
Restructured loans |  |  |  | 973 |  | 523
Nonperforming Financial Instruments | Installment and Other Consumer |  |  |  |  |  |
Financing Receivable, Modifications [Line Items] |  |  |  |  |  |
Restructured loans |  |  |  | $ 9 |  | $ 88
[1] | 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.

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