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Investments in Unconsolidated Joint Ventures - Mortgages and Other Loans Payable (Details) | 1 Months Ended | 9 Months Ended |
--- | --- | --- | ---
Oct. 31, 2021 | Sep. 30, 2021 USD ($) mortgage partner | Sep. 30, 2021 USD ($) mortgage partner extension | Dec. 31, 2020 USD ($)
Debt Instrument [Line Items] |  |  |  |
Total fixed rate debt |  | $ 1,076,153,000 | $ 1,076,153,000 | $ 1,083,683,000
Total floating rate debt |  | $ 352,581,000 | 352,581,000 | 917,677,000
1552 Broadway | Subsequent Event |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Period of extension options | 1 year |  |  |
280 Park Avenue |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Period of extension options |  | 1 year |  |
220 East 42nd Street |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Total floating rate debt |  | $ 0 | 0 | 510,000,000
Joint venture |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Total fixed rate debt |  | 8,221,640,000 | 8,221,640,000 | 5,604,858,000
Total floating rate debt |  | 2,940,796,000 | 2,940,796,000 | 4,257,792,000
Total fixed rate and floating rate debt |  | 11,162,436,000 | 11,162,436,000 | 9,862,650,000
Deferred financing costs, net |  | (139,427,000) | (139,427,000) | (113,446,000)
Total joint venture mortgages and other loans payable, net |  | $ 11,023,009,000 | $ 11,023,009,000 | 9,749,204,000
Joint venture | 717 Fifth Avenue |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Economic Interest (as a percent) |  | 10.92% | 10.92% |
Joint venture | 717 Fifth Avenue | Mortgage loan |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Interest rate, fixed rate debt (as a percent) |  | 4.45% | 4.45% |
Total fixed rate debt |  | $ 300,000,000 | $ 300,000,000 | 300,000,000
Joint venture | 717 Fifth Avenue | Mezzanine loans |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Interest rate, fixed rate debt (as a percent) |  | 5.50% | 5.50% |
Total fixed rate debt |  | $ 355,328,000 | $ 355,328,000 | 355,328,000
Joint venture | 650 Fifth Avenue |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Economic Interest (as a percent) |  | 50.00% | 50.00% |
Joint venture | 650 Fifth Avenue | Mortgage loan |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Interest rate, fixed rate debt (as a percent) |  | 4.46% | 4.46% |
Total fixed rate debt |  | $ 210,000,000 | $ 210,000,000 | 210,000,000
Joint venture | 650 Fifth Avenue | Mezzanine loans |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Interest rate, fixed rate debt (as a percent) |  | 5.45% | 5.45% |
Total fixed rate debt |  | $ 65,000,000 | $ 65,000,000 | 65,000,000
Joint venture | 21 East 66th Street |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Economic Interest (as a percent) |  | 32.28% | 32.28% |
Interest rate, fixed rate debt (as a percent) |  | 3.60% | 3.60% |
Interest rate, floating rate debt (as a percent) |  | 2.75% | 2.75% |
Total fixed rate debt |  | $ 12,000,000 | $ 12,000,000 | 12,000,000
Total floating rate debt |  | $ 643,000 | $ 643,000 | 677,000
Joint venture | 919 Third Avenue |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Economic Interest (as a percent) |  | 51.00% | 51.00% |
Interest rate, fixed rate debt (as a percent) |  | 5.12% | 5.12% |
Total fixed rate debt |  | $ 500,000,000 | $ 500,000,000 | 500,000,000
Joint venture | 1515 Broadway |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Economic Interest (as a percent) |  | 56.87% | 56.87% |
Interest rate, fixed rate debt (as a percent) |  | 3.93% | 3.93% |
Total fixed rate debt |  | $ 806,627,000 | $ 806,627,000 | 820,607,000
Joint venture | 11 Madison Avenue |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Economic Interest (as a percent) |  | 60.00% | 60.00% |
Interest rate, fixed rate debt (as a percent) |  | 3.84% | 3.84% |
Total fixed rate debt |  | $ 1,400,000,000 | $ 1,400,000,000 | 1,400,000,000
Joint venture | 800 Third Avenue |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Economic Interest (as a percent) |  | 60.52% | 60.52% |
Interest rate, fixed rate debt (as a percent) |  | 3.37% | 3.37% |
Total fixed rate debt |  | $ 177,000,000 | $ 177,000,000 | 177,000,000
Joint venture | Worldwide Plaza |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Economic Interest (as a percent) |  | 24.95% | 24.95% |
Interest rate, fixed rate debt (as a percent) |  | 3.98% | 3.98% |
Total fixed rate debt |  | $ 1,200,000,000 | $ 1,200,000,000 | 1,200,000,000
Joint venture | One Vanderbilt |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Economic Interest (as a percent) |  | 71.01% | 71.01% |
Interest rate, fixed rate debt (as a percent) |  | 2.95% | 2.95% |
Total fixed rate debt |  | $ 3,000,000,000 | $ 3,000,000,000 | 0
Total floating rate debt |  | $ 0 | $ 0 | 1,210,329,000
Joint venture | Stonehenge Portfolio |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Interest rate, fixed rate debt (as a percent) |  | 3.50% | 3.50% |
Total fixed rate debt |  | $ 195,685,000 | $ 195,685,000 | 195,899,000
Joint venture | East 400 Street 57 |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Interest rate, fixed rate debt (as a percent) |  |  |  |
Total fixed rate debt |  | $ 0 | $ 0 | 97,024,000
Joint venture | 885 Third Avenue |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Interest rate, fixed rate debt (as a percent) |  |  |  |
Total fixed rate debt |  | $ 0 | $ 0 | 272,000,000
Joint venture | 1552 Broadway |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Economic Interest (as a percent) |  | 50.00% | 50.00% |
Interest rate, floating rate debt (as a percent) |  | 2.65% | 2.65% |
Total floating rate debt |  | $ 195,000,000 | $ 195,000,000 | 195,000,000
Joint venture | 2 Herald Square |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Economic Interest (as a percent) |  | 51.00% | 51.00% |
Interest rate, floating rate debt (as a percent) |  | 1.45% | 1.45% |
Total floating rate debt |  | $ 214,500,000 | $ 214,500,000 | 214,500,000
Joint venture | 11 West 34th Street |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Economic Interest (as a percent) |  | 30.00% | 30.00% |
Interest rate, floating rate debt (as a percent) |  | 1.45% | 1.45% |
Total floating rate debt |  | $ 23,000,000 | $ 23,000,000 | 23,000,000
Joint venture | 280 Park Avenue |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Economic Interest (as a percent) |  | 50.00% | 50.00% |
Interest rate, floating rate debt (as a percent) |  | 1.73% | 1.73% |
Total floating rate debt |  | $ 1,200,000,000 | $ 1,200,000,000 | 1,200,000,000
Joint venture | 121 Greene Street |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Economic Interest (as a percent) |  | 50.00% | 50.00% |
Interest rate, floating rate debt (as a percent) |  | 2.00% | 2.00% |
Total floating rate debt |  | $ 13,367,000 | $ 13,367,000 | 15,000,000
Joint venture | 220 East 42nd Street |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Economic Interest (as a percent) |  | 51.00% | 51.00% |
Interest rate, floating rate debt (as a percent) |  | 2.75% | 2.75% |
Total floating rate debt |  | $ 510,000,000 | $ 510,000,000 | 0
Joint venture | 115 Spring Street |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Economic Interest (as a percent) |  | 51.00% | 51.00% |
Interest rate, floating rate debt (as a percent) |  | 3.40% | 3.40% |
Total floating rate debt |  | $ 65,550,000 | $ 65,550,000 | 65,550,000
Joint venture | 100 Park Avenue |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Economic Interest (as a percent) |  | 49.90% | 49.90% |
Interest rate, floating rate debt (as a percent) |  | 2.25% | 2.25% |
Total floating rate debt |  | $ 360,000,000 | $ 360,000,000 | 360,000,000
Joint venture | 15 Beekman |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Economic Interest (as a percent) |  | 20.00% | 20.00% |
Interest rate, floating rate debt (as a percent) |  | 1.50% | 1.50% |
Total floating rate debt |  | $ 32,687,000 | $ 32,687,000 | 11,212,000
Joint venture | 15 Beekman | Construction Loans |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Maximum facility capacity |  | $ 125,000,000 | $ 125,000,000 |
Joint venture | 10 East 53rd Street |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Economic Interest (as a percent) |  | 55.00% | 55.00% |
Interest rate, floating rate debt (as a percent) |  | 1.35% | 1.35% |
Total floating rate debt |  | $ 220,000,000 | $ 220,000,000 | 220,000,000
Joint venture | One Madison Avenue |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Economic Interest (as a percent) |  | 50.50% | 50.50% |
Interest rate, floating rate debt (as a percent) |  | 3.35% | 3.35% |
Total floating rate debt |  | $ 106,049,000 | $ 106,049,000 | 0
Joint venture | One Madison Avenue | Construction Loans |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Maximum facility capacity |  | $ 1,250,000,000 | $ 1,250,000,000 |
Term (in Years) |  |  | 5 years |
Number of extension options | extension |  |  | 1 |
Period of extension options |  |  | 1 year |
Joint venture | 605 West 42nd Street |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Interest rate, floating rate debt (as a percent) |  |  |  |
Total floating rate debt |  | $ 0 | $ 0 | 550,000,000
Joint venture | 55 West 46th Street |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Interest rate, floating rate debt (as a percent) |  |  |  |
Total floating rate debt |  | $ 0 | $ 0 | $ 192,524,000
Secured Debt, Initial Maturity April 2028 | Joint venture | Stonehenge Portfolio |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Total fixed rate debt |  | $ 132,400,000 | $ 132,400,000 |
Number of mortgages | partner |  | 3 | 3 |
Secured Debt, Initial Maturity July 2029 | Joint venture | Stonehenge Portfolio |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Total fixed rate debt |  | $ 63,500,000 | $ 63,500,000 |
Number of mortgages | mortgage |  | 2 | 2 |

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