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Mortgages Payable - Additional Information (Detail) - USD ($) $ in Thousands |  |  | 6 Months Ended |
--- | --- | --- | --- | ---
Feb. 14, 2020 | Dec. 12, 2018 | Jun. 30, 2020 | Dec. 31, 2019
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items] |  |  |  |
Mortgages payable, net of deferred debt issuance costs |  |  | $ 1,118,813 | $ 970,961
Mortgages |  |  |  |
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items] |  |  |  |
Mortgages payable, net of deferred debt issuance costs |  |  | $ 1,118,813 | 970,961
Rego Park II | Retail Space | Mortgages |  |  |  |
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items] |  |  |  |
Mortgages payable, net of deferred debt issuance costs |  | $ 252,544 |  |
Interest rate (in percentage) |  |  | 1.53% |
Maturity date |  |  | Dec. 12, 2025 |
Loan participation balance | $ 50,000 |  |  | 195,708
Proceeds from notes payable | $ 145,000 |  |  |
Mortgages payable, net of loan participation |  |  | $ 202,544 | 56,836
Debt instrument, description of variable rate basis |  |  | LIBOR |
Rego Park II | Retail Space | Mortgages | LIBOR |  |  |  |
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items] |  |  |  |
Basis spread over LIBOR |  | 1.35% | 1.35% |
731 Lexington Avenue | Retail Space | Mortgages |  |  |  |
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items] |  |  |  |
Interest rate (in percentage) |  |  | 1.57% |
Maturity date |  |  | Aug. 05, 2020 |
Debt instrument, description of variable rate basis |  |  | LIBOR |
731 Lexington Avenue | Retail Space | 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] |  |  |  |
Interest rate (in percentage) |  |  | 1.09% |
Maturity date |  |  | Jun. 11, 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% |
Participation Agreement | Rego Park II | Retail Space | Mortgages |  |  |  |
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items] |  |  |  |
Loan participation balance |  |  | $ 50,000 | $ 195,708

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- Definition Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 470 -SubTopic 20 -Section 50 -Paragraph 6 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=120520924&loc=SL6036836-161870 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=119993939&loc=d3e28551-108399 Reference 3: 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=120391452&loc=d3e13212-122682 + Details
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