Unsecured Borrowings - Unsecured Long-Term Borrowings after Hedging (Parenthetical) (Detail) |
Sep. 30, 2021 |
Dec. 31, 2020 |
|---|---|---|
| Debt Disclosure [Abstract] | ||
| Effective weighted average interest rates for unsecured long-term borrowings, after hedging - total | 1.61% | 2.01% |
| Effective weighted average interest rates for unsecured long-term borrowings, after hedging fixed rate obligations | 2.31% | 3.34% |
| Effective weighted average interest rates for unsecured long-term borrowings, after hedging - floating rate obligations | 1.47% | 1.70% |