Investment Securities - Summary of Gains (Losses) on Available-for-sale Securities (Details) - USD ($) $ in Thousands |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2018 |
Dec. 31, 2017 |
Dec. 31, 2016 |
|
| Investments, Debt and Equity Securities [Abstract] | |||
| Gross realized gains on sales and calls of securities available-for-sale | $ 0 | $ 0 | $ 54 |
| Gross realized losses on sales and calls of securities available-for-sale | 0 | 0 | 46 |
| Net realized gains (losses) on sales and calls of securities available-for-sale | 0 | 0 | 8 |
| Proceeds from sales and calls of securities available-for-sale | 1,075 | 0 | 7,816 |
| Tax expense on sales and calls of securities available-for-sale | $ 0 | $ 0 | $ 3 |