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Investments in Unconsolidated Joint Ventures (Balance Sheets of the Unconsolidated Joint Ventures) (Details) - USD ($) $ in Thousands | Jun. 30, 2021 | Dec. 31, 2020
--- | --- | ---
ASSETS |  |  |  |
Real estate and development in process, net |  | $ 18,072,453 |  | $ 17,818,807
Total assets |  | 22,059,076 |  | 22,858,190
LIABILITIES AND MEMBERS'/PARTNERS' EQUITY |  |  |  |
Mortgage and notes payable, net |  | 2,901,709 |  | 2,909,081
Other Liabilities |  | 370,990 |  | 412,084
Members’/Partners’ equity |  | 5,749,342 |  | 5,996,083
Total liabilities and equity / capital |  | 22,059,076 |  | 22,858,190
Carying value of the Company's investment in unconsolidated joint ventures |  | 1,305,589 |  | 1,310,478
Right-of-use assets - finance leases |  | 237,765 |  | 237,393
Right of use assets - operating leases |  | 170,331 | [1] | 146,406
Lease liabilities - finance leases |  | 243,381 |  | 236,492
Lease liabilities - operating leases |  | 226,594 |  | 201,713
Unconsolidated Joint Ventures [Member] |  |  |  |
ASSETS |  |  |  |
Real estate and development in process, net | [2] | 4,751,881 |  | 4,708,571
Other assets |  | 521,766 |  | 531,071
Total assets |  | 5,273,647 |  | 5,239,642
LIABILITIES AND MEMBERS'/PARTNERS' EQUITY |  |  |  |
Mortgage and notes payable, net |  | 2,715,677 |  | 2,637,911
Other Liabilities | [3] | 600,402 |  | 650,433
Members’/Partners’ equity |  | 1,957,568 |  | 1,951,298
Total liabilities and equity / capital |  | 5,273,647 |  | 5,239,642
Company's share of equity |  | 929,421 |  | 936,087
Basis differentials | [4] | 340,681 |  | 337,832
Carying value of the Company's investment in unconsolidated joint ventures | [5] | 1,270,102 |  | 1,273,919
Right-of-use assets - finance leases |  | 248,900 |  | 248,900
Right of use assets - operating leases |  | 22,000 |  | 22,500
Lease liabilities - finance leases |  | 387,100 |  | 388,700
Lease liabilities - operating leases |  | 29,400 |  | 29,000
Unconsolidated Joint Ventures [Member] |  |  |  |
LIABILITIES AND MEMBERS'/PARTNERS' EQUITY |  |  |  |
Other Liabilities |  | 35,500 |  | 36,600
Colorado Center |  |  |  |
LIABILITIES AND MEMBERS'/PARTNERS' EQUITY |  |  |  |
Basis differentials |  | 305,902 |  | 307,328
Carying value of the Company's investment in unconsolidated joint ventures | [6] | 229,564 |  | 227,671
Gateway Commons Complex [Member] |  |  |  |
LIABILITIES AND MEMBERS'/PARTNERS' EQUITY |  |  |  |
Basis differentials |  | 52,104 |  | 51,875
Carying value of the Company's investment in unconsolidated joint ventures | [6] | 331,389 |  | 336,206
Dock 72 |  |  |  |
LIABILITIES AND MEMBERS'/PARTNERS' EQUITY |  |  |  |
Basis differentials |  | (51,137) |  | (52,243)
Carying value of the Company's investment in unconsolidated joint ventures | [6] | $ 28,116 |  | $ 29,536
[1] | See Note 4.
[2] | At June 30, 2021 and December 31, 2020, this amount included right of use assets - finance leases totaling approximately $248.9 million and $248.9 million, respectively, and right of use assets - operating leases totaling approximately $22.0 million and $22.5 million, respectively.
[3] | At June 30, 2021 and December 31, 2020, this amount included lease liabilities - finance leases totaling approximately $387.1 million and $388.7 million, respectively, and lease liabilities - operating leases totaling approximately $29.4 million and $29.0 million, respectively.
[4] | 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 majority of the Company’s basis differences are as follows:
| June 30, 2021 |  | December 31, 2020
Property | (in thousands)
Colorado Center | $ | 305,902 |  |  | $ | 307,328 |
Gateway Commons | 52,104 |  |  | 51,875 |
Dock 72 | (51,137) |  |  | (52,243) |
These basis differentials (excluding land) will be amortized over the remaining lives of the related assets and liabilities.
[5] | Investments with deficit balances aggregating approximately $35.5 million and $36.6 million at June 30, 2021 and December 31, 2020, respectively, are reflected within Other Liabilities in the Company’s Consolidated Balance Sheets.
[6] | Investments with deficit balances aggregating approximately $35.5 million and $36.6 million at June 30, 2021 and December 31, 2020, respectively, are included within Other Liabilities in the Company’s Consolidated Balance Sheets.

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