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Mortgages Payable - Additional Information (Detail) |  | 9 Months Ended
--- | --- | ---
Oct. 03, 2018 | Sep. 30, 2018
Paramus | Mortgages |  |
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items] |  |
Maturity date |  | Oct. 05, 2018
Rego Park II | Retail Site | Mortgages |  |
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items] |  |
Maturity date |  | Nov. 30, 2018
Debt Instrument, Description of Variable Rate Basis |  | LIBOR
Rego Park II | Retail Site | Mortgages | LIBOR |  |
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items] |  |
Basis spread over LIBOR |  | 1.85%
731 Lexington Avenue | Retail Site | Mortgages |  |
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items] |  |
Maturity date |  | Aug. 01, 2022
Debt Instrument, Description of Variable Rate Basis |  | LIBOR
731 Lexington Avenue | Retail Site | Mortgages | LIBOR |  |
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items] |  |
Basis spread over LIBOR |  | 1.40%
731 Lexington Avenue | Office Space | Mortgages |  |
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items] |  |
Maturity date |  | Jun. 01, 2024
Debt Instrument, Description of Variable Rate Basis |  | LIBOR
731 Lexington Avenue | Office Space | Mortgages | LIBOR |  |
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items] |  |
Basis spread over LIBOR |  | 0.90%
IKEA | Paramus | Tenant Occupant |  |
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items] |  |
Maturity date |  | Oct. 04, 2021
Fixed interest rate on the debt |  | 2.90%
Subsequent Event | Paramus | Mortgages |  |
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items] |  |
Maturity date | Oct. 04, 2021 |
Subsequent Event | IKEA | Paramus | Tenant Occupant |  |
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items] |  |
Fixed interest rate on the debt | 4.72% |

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- Definition Contractual interest rate for funds borrowed, under the debt agreement. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22(a)(1)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
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- Definition Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22(a)(2)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (bbb)(2) -URI http://asc.fasb.org/extlink&oid=99377789&loc=d3e19207-110258 + Details
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