Investment Securities - Proceeds from Sale, Gross Gains (Losses) Realized on Sales, Maturities and Other-Than-Temporary Impairment Charges Related to Securities Available for Sale (Detail) - USD ($) $ in Thousands |
3 Months Ended | |
|---|---|---|
Mar. 31, 2026 |
Mar. 31, 2025 |
|
| Net Investment Income [Line Items] | ||
| Proceeds from maturities and redemptions of available-for-sale securities | $ 0 | $ 48,519 |
| Gain Losses Maturities And Impairment | 229 | (5,142) |
| Sales | ||
| Net Investment Income [Line Items] | ||
| Gross Gains | 0 | 0 |
| Gross Losses | 0 | (5,142) |
| Gain Losses Maturities And Impairment | 0 | (5,142) |
| Maturities | ||
| Net Investment Income [Line Items] | ||
| Gross Gains | 229 | 0 |
| Gross Losses | 0 | 0 |
| Gain Losses Maturities And Impairment | $ 229 | $ 0 |