Commitments and Contingencies - Additional Information (Detail) ft² in Thousands	1 Months Ended				3 Months Ended
	Oct. 31, 2021 USD ($)	Mar. 31, 2016 USD ($)	Jun. 30, 2014 USD ($) ft²	Feb. 28, 2014 fire	Mar. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2001 a
Loss Contingencies [Line Items]
Mortgages payable, net of deferred debt issuance costs					$ 1,156,517,000	$ 1,156,170,000
Standby letters of credit, outstanding					960,000
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
Purchase option not exercised amount included in triple net rent over remainder of lease					$ 68,000,000
Fixed interest rate on the debt					4.72%
Debt instrument maturity date					Oct. 04, 2021
Triple-net rent, annual amount					$ 700,000
Forecast | Tenant Occupant | Paramus | IKEA
Loss Contingencies [Line Items]
Lease purchase option amount	$ 75,000,000
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
Mortgages payable, net of deferred debt issuance costs	$ 68,000,000
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					$ 275,000
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