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Investments in Unconsolidated Joint Ventures (Balance Sheets of the Unconsolidated Joint Ventures) (Details) - USD ($) $ in Thousands | Sep. 30, 2024 | Dec. 31, 2023
--- | --- | ---
ASSETS |  |  |
Total real estate |  | $ 20,900,979 | $ 20,593,459
Total assets |  | 26,405,536 | 26,026,149
LIABILITIES AND MEMBERS'/PARTNERS' EQUITY |  |  |
Mortgage and notes payable, net |  | 4,275,155 | 4,166,379
Other Liabilities |  | 407,441 | 445,947
Members’/Partners’ equity |  | 5,759,209 | 5,876,697
Total liabilities and equity / capital |  | 26,405,536 | 26,026,149
Carying value of the Company's investment in unconsolidated joint ventures |  | 1,421,886 | 1,377,319
Operating Lease, Right-of-Use Asset | [1] | 339,804 | 324,298
Lease Liabilities - Operating Leases |  | 389,444 | 350,391
Unconsolidated Joint Ventures [Member] |  |  |
ASSETS |  |  |
Total real estate | [2] | 5,756,008 | 5,811,763
Other assets | [3] | 651,956 | 682,291
Total assets |  | 6,407,964 | 6,494,054
LIABILITIES AND MEMBERS'/PARTNERS' EQUITY |  |  |
Mortgage and notes payable, net |  | 3,198,547 | 3,351,873
Other Liabilities | [4] | 294,795 | 361,357
Members’/Partners’ equity |  | 2,914,622 | 2,780,824
Total liabilities and equity / capital |  | 6,407,964 | 6,494,054
Company's share of equity |  | 1,334,102 | 1,278,483
Basis differentials | [5] | 57,047 | 58,933
Carying value of the Company's investment in unconsolidated joint ventures | [6] | 1,391,149 | 1,337,416
Operating Lease, Right-of-Use Asset |  | 19,200 | 20,100
Sales-type lease receivable, net |  | 14,100 | 13,900
Lease Liabilities - Operating Leases |  | 30,500 | 30,500
Unconsolidated Joint Ventures [Member] |  |  |
LIABILITIES AND MEMBERS'/PARTNERS' EQUITY |  |  |
Other Liabilities |  | 30,700 | 39,900
Colorado Center |  |  |
LIABILITIES AND MEMBERS'/PARTNERS' EQUITY |  |  |
Basis differentials |  | 296,758 | 298,906
Carying value of the Company's investment in unconsolidated joint ventures | [7] | 234,972 | 237,815
200 Fifth Avenue JV LLC |  |  |
LIABILITIES AND MEMBERS'/PARTNERS' EQUITY |  |  |
Basis differentials |  | 51,779 | 58,308
Carying value of the Company's investment in unconsolidated joint ventures | [7] | 68,563 | 75,718
Gateway Commons Complex [Member] |  |  |
LIABILITIES AND MEMBERS'/PARTNERS' EQUITY |  |  |
Basis differentials |  | 51,009 | 48,971
Carying value of the Company's investment in unconsolidated joint ventures | [7] | 393,679 | 376,834
Safeco Plaza REIT LLC |  |  |
LIABILITIES AND MEMBERS'/PARTNERS' EQUITY |  |  |
Basis differentials |  | (29,032) | (29,678)
Carying value of the Company's investment in unconsolidated joint ventures | [7] | 47,510 | 44,734
360 PAS Holdco LLC |  |  |
LIABILITIES AND MEMBERS'/PARTNERS' EQUITY |  |  |
Basis differentials |  | (114,202) | (116,534)
Carying value of the Company's investment in unconsolidated joint ventures | [7] | 69,538 | 42,988
Dock 72 |  |  |
LIABILITIES AND MEMBERS'/PARTNERS' EQUITY |  |  |
Other Liabilities | [7] | 7,065 | 11,890
Basis differentials |  | (92,930) | (95,521)
Platform 16 |  |  |
LIABILITIES AND MEMBERS'/PARTNERS' EQUITY |  |  |
Basis differentials |  | (142,670) | (143,052)
Carying value of the Company's investment in unconsolidated joint ventures | [7] | $ 55,381 | $ 45,564
[1] | See Note 4.
[2] | At September 30, 2024 and December 31, 2023, this amount included right of use assets - operating leases totaling approximately $19.2 million and $20.1 million, respectively.
[3] | At September 30, 2024 and December 31, 2023, this amount included sales-type lease receivable, net totaling approximately $14.1 million and $13.9 million, respectively.
[4] | At September 30, 2024 and December 31, 2023, this amount included lease liabilities - operating leases totaling approximately $30.5 million.
[5] | This amount represents the aggregate difference between the Company’s historical cost basis and the basis reflected at the joint venture level, which is typically amortized over the life of the related assets and liabilities. Basis differentials result from impairments of investments, acquisitions through joint ventures with no change in control and upon the transfer of assets that were previously owned by the Company into a joint venture. In addition, certain acquisition, transaction and other costs may not be reflected in the net assets at the joint venture level. The Company’s basis differences include:
| September 30, 2024 |  | December 31, 2023
Property | (in thousands)
Colorado Center | $ | 296,758 |  |  | $ | 298,906 |
200 Fifth Avenue | 51,779 |  |  | 58,308 |
Gateway Commons | 51,009 |  |  | 48,971 |
Safeco Plaza | (29,032) |  |  | (29,678) |
360 Park Avenue South | (114,202) |  |  | (116,534) |
Dock 72 | (92,930) |  |  | (95,521) |
Platform 16 | (142,670) |  |  | (143,052) |
These basis differentials (excluding land) will be amortized over the remaining lives of the related assets and liabilities.
[6] | Investments with deficit balances aggregating approximately $30.7 million and $39.9 million at September 30, 2024 and December 31, 2023, respectively, are reflected within Other Liabilities in the Company’s Consolidated Balance Sheets.
[7] | Investments with deficit balances aggregating approximately $30.7 million and $39.9 million at September 30, 2024 and December 31, 2023, respectively, are included within Other Liabilities in the Company’s Consolidated Balance Sheets.

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