Commitments and Contingencies - Additional Information (Detail)		1 Months Ended		3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 24, 2014 USD ($)	Mar. 31, 2016 USD ($)	Feb. 28, 2014 Fires	Jun. 30, 2017 USD ($) ft²	Jun. 30, 2016 USD ($)	Jun. 30, 2017 USD ($) ft²	Jun. 30, 2016 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2001 a
Loss Contingencies [Line Items]
Insurance Maximum Coverage Per occurrence				$ 300,000,000		$ 300,000,000
Insurance Maximum Coverage Per Property						300,000,000
Annual property rental				38,264,000	$ 38,878,000	76,537,000	$ 75,531,000
Deferred leasing cost, net				46,106,000		46,106,000			$ 48,387,000
Mortgages payable, net of deferred debt issuance costs				1,239,729,000		1,239,729,000			$ 1,052,359,000
Standby letters of credit, outstanding				$ 2,074,000		$ 2,074,000
Rego Park I [Member] | Sears [Member]
Loss Contingencies [Line Items]
Area of property | ft²				195,000		195,000
Annual property rental						$ 10,337,000
Straight line rent receivable						4,460,000
Deferred leasing cost, net				$ 468,000		$ 468,000
Lease expiration date						2021-03
Number of fires | Fires			2
Rego Park I [Member] | Sears [Member] | Estimated Future Damages [Member]
Loss Contingencies [Line Items]
Loss contingency, damages sought, value		$ 650,000
Rego Park I [Member] | Sears [Member] | Minimum [Member]
Loss Contingencies [Line Items]
Loss contingency, damages sought, value	$ 4,000,000
Rego Park I [Member] | Sears [Member] | Minimum [Member] | Estimated Future Damages [Member]
Loss Contingencies [Line Items]
Loss contingency, damages sought, value	$ 25,000,000
Rego Park I [Member] | Sears [Member] | Maximum [Member] | Estimated Future Damages [Member]
Loss Contingencies [Line Items]
Reasonably possible losses				650,000		$ 650,000
Paramus [Member] | IKEA [Member] | Tenant Occupant [Member]
Loss Contingencies [Line Items]
Area of land | a										30.3
Mortgages payable, net of deferred debt issuance costs				$ 68,000,000		$ 68,000,000
Fixed interest rate on the debt				2.90%		2.90%
Debt instrument maturity date						2018-10
Triple-net rent, annual amount						$ 700,000
Paramus [Member] | Scenario, Forecast [Member] | IKEA [Member] | Tenant Occupant [Member]
Loss Contingencies [Line Items]
Lease purchase option amount								$ 75,000,000
Loan Amortization Period								20 years
Lease term range as Lessor								20 years
Purchase option not exercised amount included in triple net rent over remainder of lease								$ 68,000,000
Purchase option exercised, gain on sale of land								60,000,000
Purchase option exercised, net cash proceeds from sale of land								$ 7,000,000
The Kings Plaza Regional Shopping Center [Member]
Loss Contingencies [Line Items]
Loss contingency, damages sought, value						22,070,000
All Risk Property and Rental Value [Member]
Loss Contingencies [Line Items]
Insurance Maximum Coverage Per occurrence				$ 1,700,000,000		1,700,000,000
Terrorism Coverage Including NBCR [Member]
Loss Contingencies [Line Items]
Insurance Maximum Coverage Per occurrence				$ 1,700,000,000		1,700,000,000
Insurance maximum coverage in aggregate						$ 1,700,000,000
NBCR [Member]
Loss Contingencies [Line Items]
Insurance coverage end date						2020-12
Self insured responsibility				17.00%		17.00%
Federal government responsibility				83.00%		83.00%
NBCR [Member] | FNSIC [Member]
Loss Contingencies [Line Items]
Insurance deductible						$ 293,000