Allowance for Loan Losses - Weighted Average Annualized Balance of Recorded Investment and Interest Income on Impaired Loans (Details) - USD ($) $ in Thousands |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
|
| Financing Receivable Modifications [Line Items] | |||
| Average Recorded Investment | $ 9,229 | $ 5,899 | $ 14,469 |
| Interest Income after Impairment | 75 | 51 | 677 |
| Residential Properties | |||
| Financing Receivable Modifications [Line Items] | |||
| Average Recorded Investment | 1,323 | 1,970 | 27 |
| Interest Income after Impairment | 20 | 14 | 2 |
| Commercial Real Estate | |||
| Financing Receivable Modifications [Line Items] | |||
| Average Recorded Investment | 2,403 | 2,252 | 6,487 |
| Interest Income after Impairment | 50 | 17 | 281 |
| Commercial and Industrial Loans | |||
| Financing Receivable Modifications [Line Items] | |||
| Average Recorded Investment | 5,503 | 1,673 | 7,850 |
| Interest Income after Impairment | $ 5 | 20 | 394 |
| Consumer Loans | |||
| Financing Receivable Modifications [Line Items] | |||
| Average Recorded Investment | $ 4 | $ 105 | |