Unsecured Credit Agreements - Summary of Unsecured Credit Agreements (Parenthetical) (Detail) |
6 Months Ended | |
|---|---|---|
Jun. 30, 2020 |
Dec. 31, 2019 |
|
| 2020 Unsecured Term Loan | ||
| Debt Instrument [Line Items] | ||
| Maturity date | Aug. 31, 2020 | |
| Debt instrument extension options, description | two six-month extensions | |
| Maturity extension fee on outstanding principal balance percentage | 0.05% | |
| Debt instrument maturity date extension | Feb. 02, 2021 | |
| Unsecured Debt | 2020 Unsecured Term Loan | ||
| Debt Instrument [Line Items] | ||
| Maturity date | Feb. 28, 2021 | |
| Unsecured Debt | 1 Month LIBOR | ||
| Debt Instrument [Line Items] | ||
| Interest rate | 0.16% | 1.76% |