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Organization and Basis of Presentation - Schedule of Commercial Office Properties (Details) $ in Thousands | 12 Months Ended |  |
--- | --- | --- | ---
Dec. 31, 2019 USD ($) ft² building shares | Dec. 31, 2018 USD ($) | Dec. 31, 2017 USD ($)
Real estate properties |  |  |
Number of Properties | building | 71 |  |
Approximate Square Feet | 27,607,971 |  |
Weighted Average Occupancy unaudited (as a percent) | 94.30% |  |
Debt and preferred equity investments including investments held by unconsolidated joint ventures | $ | $ 1,580,306 | $ 2,099,393 | $ 2,114,041
Number of shares to be received on redemption of one unit of limited partnership interests (shares) | shares | 1 |  |
Commercial properties |  |  |
Real estate properties |  |  |
Number of Properties | building | 61 |  |
Approximate Square Feet | 25,499,092 |  |
Weighted Average Occupancy unaudited (as a percent) | 94.20% |  |
Residential |  |  |
Real estate properties |  |  |
Number of Properties | building | 10 |  |
Approximate Square Feet | 2,108,879 |  |
Weighted Average Occupancy unaudited (as a percent) | 95.70% |  |
Managed office properties |  |  |
Real estate properties |  |  |
Number of Properties | building | 2 |  |
Approximate Square Feet | 2,100,000 |  |
Debt and preferred equity investments including investments held by unconsolidated joint ventures | $ | $ 1,700,000 |  |
Debt and preferred equity investments and other financing receivables included in other balance sheet items | $ | $ 100,000 |  |
Consolidated properties |  |  |
Real estate properties |  |  |
Number of Properties | building | 43 |  |
Approximate Square Feet | 14,438,964 |  |
Consolidated properties | Commercial properties |  |  |
Real estate properties |  |  |
Number of Properties | building | 41 |  |
Approximate Square Feet | 13,993,859 |  |
Consolidated properties | Residential |  |  |
Real estate properties |  |  |
Number of Properties | building | 2 |  |
Approximate Square Feet | 445,105 |  |
Unconsolidated properties |  |  |
Real estate properties |  |  |
Number of Properties | building | 28 |  |
Approximate Square Feet | 13,169,007 |  |
Unconsolidated properties | Commercial properties |  |  |
Real estate properties |  |  |
Number of Properties | building | 20 |  |
Approximate Square Feet | 11,505,233 |  |
Unconsolidated properties | Residential |  |  |
Real estate properties |  |  |
Number of Properties | building | 8 |  |
Approximate Square Feet | 1,663,774 |  |
Manhattan |  |  |
Real estate properties |  |  |
Number of Properties | building | 52 |  |
Approximate Square Feet | 24,402,292 |  |
Weighted Average Occupancy unaudited (as a percent) | 94.60% |  |
Manhattan | Office |  |  |
Real estate properties |  |  |
Number of Properties | building | 30 |  |
Approximate Square Feet | 23,603,274 |  |
Weighted Average Occupancy unaudited (as a percent) | 94.50% |  |
Manhattan | Retail |  |  |
Real estate properties |  |  |
Number of Properties | building | 14 |  |
Approximate Square Feet | 609,480 |  |
Weighted Average Occupancy unaudited (as a percent) | 98.40% |  |
Manhattan | Development/Redevelopment |  |  |
Real estate properties |  |  |
Number of Properties | building | 7 |  |
Approximate Square Feet | 189,538 |  |
Weighted Average Occupancy unaudited (as a percent) | 84.90% |  |
Manhattan | Fee Interest |  |  |
Real estate properties |  |  |
Number of Properties | building | 1 |  |
Approximate Square Feet | 0 |  |
Weighted Average Occupancy unaudited (as a percent) | 0.00% |  |
Manhattan | Residential |  |  |
Real estate properties |  |  |
Number of Properties | building | 10 |  |
Approximate Square Feet | 2,108,879 |  |
Weighted Average Occupancy unaudited (as a percent) | 95.70% |  |
Manhattan | Consolidated properties |  |  |
Real estate properties |  |  |
Number of Properties | building | 32 |  |
Approximate Square Feet | 12,897,059 |  |
Manhattan | Consolidated properties | Office |  |  |
Real estate properties |  |  |
Number of Properties | building | 20 |  |
Approximate Square Feet | 12,387,091 |  |
Manhattan | Consolidated properties | Retail |  |  |
Real estate properties |  |  |
Number of Properties | building | 6 |  |
Approximate Square Feet | 320,430 |  |
Manhattan | Consolidated properties | Development/Redevelopment |  |  |
Real estate properties |  |  |
Number of Properties | building | 6 |  |
Approximate Square Feet | 189,538 |  |
Manhattan | Consolidated properties | Fee Interest |  |  |
Real estate properties |  |  |
Number of Properties | building | 0 |  |
Approximate Square Feet | 0 |  |
Manhattan | Consolidated properties | Residential |  |  |
Real estate properties |  |  |
Number of Properties | building | 2 |  |
Approximate Square Feet | 445,105 |  |
Manhattan | Consolidated properties | Dual property type, retail portion |  |  |
Real estate properties |  |  |
Approximate Square Feet | 270,132 |  |
Manhattan | Consolidated properties | Dual property type, residential portion |  |  |
Real estate properties |  |  |
Approximate Square Feet | 222,855 |  |
Manhattan | Unconsolidated properties |  |  |
Real estate properties |  |  |
Number of Properties | building | 20 |  |
Approximate Square Feet | 11,505,233 |  |
Manhattan | Unconsolidated properties | Office |  |  |
Real estate properties |  |  |
Number of Properties | building | 10 |  |
Approximate Square Feet | 11,216,183 |  |
Manhattan | Unconsolidated properties | Retail |  |  |
Real estate properties |  |  |
Number of Properties | building | 8 |  |
Approximate Square Feet | 289,050 |  |
Manhattan | Unconsolidated properties | Development/Redevelopment |  |  |
Real estate properties |  |  |
Number of Properties | building | 1 |  |
Approximate Square Feet | 0 |  |
Manhattan | Unconsolidated properties | Fee Interest |  |  |
Real estate properties |  |  |
Number of Properties | building | 1 |  |
Approximate Square Feet | 0 |  |
Manhattan | Unconsolidated properties | Residential |  |  |
Real estate properties |  |  |
Number of Properties | building | 8 |  |
Approximate Square Feet | 1,663,774 |  |
Suburban |  |  |
Real estate properties |  |  |
Number of Properties | building | 9 |  |
Approximate Square Feet | 1,096,800 |  |
Weighted Average Occupancy unaudited (as a percent) | 86.40% |  |
Suburban | Office |  |  |
Real estate properties |  |  |
Number of Properties | building | 8 |  |
Approximate Square Feet | 1,044,800 |  |
Weighted Average Occupancy unaudited (as a percent) | 85.70% |  |
Suburban | Retail |  |  |
Real estate properties |  |  |
Number of Properties | building | 1 |  |
Approximate Square Feet | 52,000 |  |
Weighted Average Occupancy unaudited (as a percent) | 100.00% |  |
Suburban | Consolidated properties |  |  |
Real estate properties |  |  |
Number of Properties | building | 9 |  |
Approximate Square Feet | 1,096,800 |  |
Suburban | Consolidated properties | Office |  |  |
Real estate properties |  |  |
Number of Properties | building | 8 |  |
Approximate Square Feet | 1,044,800 |  |
Suburban | Consolidated properties | Retail |  |  |
Real estate properties |  |  |
Number of Properties | building | 1 |  |
Approximate Square Feet | 52,000 |  |
Suburban | Unconsolidated properties |  |  |
Real estate properties |  |  |
Number of Properties | building | 0 |  |
Approximate Square Feet | 0 |  |
Suburban | Unconsolidated properties | Office |  |  |
Real estate properties |  |  |
Number of Properties | building | 0 |  |
Approximate Square Feet | 0 |  |
Suburban | Unconsolidated properties | Retail |  |  |
Real estate properties |  |  |
Number of Properties | building | 0 |  |
Approximate Square Feet | 0 |  |

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