Mortgage-Backed Securities - Summary of Investment in Mortgage Backed Securities (Parenthetical) (Detail) |
3 Months Ended | 12 Months Ended |
|---|---|---|
Mar. 31, 2026 |
Dec. 31, 2025 |
|
| Minimum [Member] | ||
| Mortgage Backed Securities [Line Items] | ||
| Mortgage backed securities, maturity period | 10 years | 10 years |
| Minimum [Member] | Subordinate Residential Transition [Member] | ||
| Mortgage Backed Securities [Line Items] | ||
| Mortgage backed securities, maturity period | 1 year | |
| Maximum [Member] | Subordinate Residential Transition [Member] | ||
| Mortgage Backed Securities [Line Items] | ||
| Mortgage backed securities, maturity period | 5 years |