Accumulated Other Comprehensive Income - Schedule of Reclassifications Out of Accumulated Other Comprehensive Income (Detail) - USD ($) $ in Thousands |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2019 |
Dec. 31, 2018 |
Dec. 31, 2017 |
|
| Accumulated Other Comprehensive Income (Loss) [Line Items] | |||
| Realized gains on sales of investment securities | $ 3,152 | $ (7,656) | $ 2,343 |
| Amount reclassified from accumulated other comprehensive income | 776 | (1,883) | (899) |
| Amount reclassified from accumulated other comprehensive income | $ 2,376 | $ (5,773) | 1,444 |
| Income Tax Expense [Member] | |||
| Accumulated Other Comprehensive Income (Loss) [Line Items] | |||
| Amount reclassified from accumulated other comprehensive income | $ 899 | ||