Loans - Composition of TDRs by Accrual and Nonaccrual Status (Details) - USD ($) $ in Thousands |
Sep. 30, 2017 |
Dec. 31, 2016 |
|---|---|---|
| Accounts Notes And Loans Receivable [Line Items] | ||
| Troubled Debt Restructurings, Nonaccrual | $ 6,494 | $ 8,238 |
| Commercial and Industrial Loans | ||
| Accounts Notes And Loans Receivable [Line Items] | ||
| Troubled Debt Restructurings, Nonaccrual | 5,216 | 3,359 |
| Principal Reduction and Extended Maturity | Commercial and Industrial Loans | ||
| Accounts Notes And Loans Receivable [Line Items] | ||
| Troubled Debt Restructurings, Accrual | 225 | 317 |
| Troubled Debt Restructurings, Nonaccrual | 2,522 | 3,109 |
| Troubled Debt Restructurings, Total | $ 2,747 | $ 3,426 |