Commitments and Contingencies - Additional Information (Detail) ft² in Thousands		1 Months Ended			6 Months Ended
	Apr. 05, 2018 USD ($)	Oct. 31, 2021 USD ($)	Mar. 31, 2016 USD ($)	Feb. 28, 2014 fire	Jun. 30, 2020 USD ($)	Dec. 31, 2019 USD ($)	Jun. 30, 2014 ft²	Dec. 31, 2001 a
Loss Contingencies [Line Items]
Mortgages payable, net of deferred debt issuance costs					$ 1,118,813,000	$ 970,961,000
Real property transfer tax	$ 23,797,000
Additional real property transfer tax expense	15,874,000
Real property transfer tax interest	$ 7,923,000
Standby letters of credit, outstanding					1,030,000
Rego Park I | Sears
Loss Contingencies [Line Items]
Area of property (in sqft.) | ft²							195
Number of fires | fire				2
Rego Park I | Sears | Estimated Future Damages
Loss Contingencies [Line Items]
Loss contingency, damages sought, value			$ 650,000
Rego Park I | Sears | Minimum
Loss Contingencies [Line Items]
Loss contingency, damages sought, value					4,000,000
Rego Park I | Sears | Minimum | Estimated Future Damages
Loss Contingencies [Line Items]
Loss contingency, damages sought, value					25,000,000
Rego Park I | Sears | Maximum | Estimated Future Damages
Loss Contingencies [Line Items]
Reasonably possible losses					$ 650,000
Tenant Occupant | Paramus | IKEA
Loss Contingencies [Line Items]
Area of land (in acres) | a								30.3
Fixed interest rate on the debt					4.72%
Triple-net rent, annual amount					$ 700,000
Mortgages payable, net of deferred debt issuance costs					$ 68,000,000
Debt instrument maturity date					Oct. 04, 2021
Forecast | Tenant Occupant | Paramus | IKEA
Loss Contingencies [Line Items]
Lease purchase option amount		$ 75,000,000
Purchase option not exercised amount included in triple net rent over remainder of lease		68,000,000
Purchase option exercised, net cash proceeds from sale of land		7,000,000
Purchase option exercised, gain on sale of land		$ 60,000,000
Lease term range as Lessor		20 years
Loan amortization period		20 years
All Risk Property and Rental Value
Loss Contingencies [Line Items]
Insurance maximum coverage per occurrence					$ 1,700,000,000
Terrorism Coverage Including NBCR
Loss Contingencies [Line Items]
Insurance maximum coverage per occurrence					1,700,000,000
Insurance maximum coverage in aggregate					$ 1,700,000,000
NBCR
Loss Contingencies [Line Items]
Insurance coverage end date					Dec. 01, 2027
Federal government responsibility					80.00%
NBCR | FNSIC
Loss Contingencies [Line Items]
Insurance deductible					$ 268,000
Self insured responsibility					20.00%
General Liability
Loss Contingencies [Line Items]
Insurance maximum coverage per occurrence					$ 300,000,000
Insurance maximum coverage per property					300,000,000
Disease Coverage
Loss Contingencies [Line Items]
Insurance maximum coverage per occurrence					$ 1,000,000