Securities - Gross Realized Gains or Losses (Detail) - USD ($) |
3 Months Ended | 9 Months Ended | |||
|---|---|---|---|---|---|
Sep. 30, 2026 |
Mar. 31, 2026 |
Sep. 30, 2025 |
Sep. 30, 2026 |
Sep. 30, 2025 |
|
| Debt Securities, Available-for-Sale, Realized Gain (Loss) [Abstract] | |||||
| Gross realized gains | $ 0 | $ 0 | $ 0 | $ 0 | |
| Gross realized losses | 0 | $ (347,000) | 0 | (347,000) | 0 |
| Net realized losses | 0 | 0 | (347,000) | 0 | |
| Tax benefit related to net realized losses | $ 0 | $ 0 | $ (73,000) | $ 0 | |