Investments in Unconsolidated Joint Ventures (Balance Sheets of the Unconsolidated Joint Ventures) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2023		Dec. 31, 2022		Dec. 31, 2021
ASSETS
Total real estate		$ 20,593,459		$ 19,496,442
Total assets		26,026,149		24,207,669
LIABILITIES AND MEMBERS'/PARTNERS' EQUITY
Mortgage and notes payable, net		4,166,379		3,272,368
Other Liabilities		445,947		450,918
Members’/Partners’ equity		5,876,697		6,132,919
Total liabilities and equity / capital		26,026,149		24,207,669
Carying value of the Company's investment in unconsolidated joint ventures		1,377,319		1,715,911
Right-of-use assets - finance leases		401,680	[1]	237,510
Operating Lease, Right-of-Use Asset	[1]	324,298		167,351
Lease liabilities - finance leases		417,961		249,335
Lease Liabilities - Operating Leases		350,391		204,686
Sales-type lease receivable, net		13,953		13,028
Unconsolidated Joint Ventures [Member]
ASSETS
Total real estate	[2]	5,811,763		6,537,554
Other assets		682,291	[3]	756,786
Total assets		6,494,054		7,294,340
LIABILITIES AND MEMBERS'/PARTNERS' EQUITY
Mortgage and notes payable, net		3,351,873		4,022,746
Other Liabilities	[4]	361,357		716,271
Members’/Partners’ equity		2,780,824		2,555,323
Total liabilities and equity / capital		6,494,054		7,294,340
Company's share of equity		1,278,483		1,238,929
Basis differentials	[5]	58,933		391,556
Carying value of the Company's investment in unconsolidated joint ventures	[6]	1,337,416		1,630,485
Right-of-use assets - finance leases				248,900
Operating Lease, Right-of-Use Asset		20,100		21,200
Lease liabilities - finance leases				382,200
Lease Liabilities - Operating Leases		30,500		30,500
Impairment loss on investment		(272,603)	[7]	(50,705)	[7]	$ 0
Gain on Unconsolidated Joint Venture Investment		35,756	[8]	0		$ 0
Sales-type lease receivable, net		13,900
Unconsolidated Joint Ventures [Member]
LIABILITIES AND MEMBERS'/PARTNERS' EQUITY
Other Liabilities		39,900		85,400
Colorado Center
LIABILITIES AND MEMBERS'/PARTNERS' EQUITY
Basis differentials		298,906		301,820
Carying value of the Company's investment in unconsolidated joint ventures	[9]	237,815		233,862
200 Fifth Avenue JV LLC
LIABILITIES AND MEMBERS'/PARTNERS' EQUITY
Basis differentials		58,308		94,497
Carying value of the Company's investment in unconsolidated joint ventures	[9]	75,718		120,083
Impairment loss on investment		33,400
200 Fifth Avenue JV LLC | Unconsolidated Joint Ventures [Member]
LIABILITIES AND MEMBERS'/PARTNERS' EQUITY
Impairment loss on investment		33,400
Gateway Commons Complex [Member]
LIABILITIES AND MEMBERS'/PARTNERS' EQUITY
Basis differentials		48,971		47,808
Carying value of the Company's investment in unconsolidated joint ventures	[9]	376,834		324,038
BP/CRF Metropolitan Square LLC [Member]
LIABILITIES AND MEMBERS'/PARTNERS' EQUITY
Other Liabilities	[9]			37,629
Gain on Unconsolidated Joint Venture Investment		35,800
Safeco Plaza REIT LLC
LIABILITIES AND MEMBERS'/PARTNERS' EQUITY
Basis differentials		(29,678)		(15)
Carying value of the Company's investment in unconsolidated joint ventures	[9]	44,734		69,785
Impairment loss on investment		29,900
Safeco Plaza REIT LLC | Unconsolidated Joint Ventures [Member]
LIABILITIES AND MEMBERS'/PARTNERS' EQUITY
Impairment loss on investment		29,900
360 PAS Holdco LLC
LIABILITIES AND MEMBERS'/PARTNERS' EQUITY
Basis differentials		(116,534)		3,798
Carying value of the Company's investment in unconsolidated joint ventures		42,988		114,992	[9]
Impairment loss on investment		54,000
360 PAS Holdco LLC | Unconsolidated Joint Ventures [Member]
LIABILITIES AND MEMBERS'/PARTNERS' EQUITY
Impairment loss on investment		54,000
Dock 72
LIABILITIES AND MEMBERS'/PARTNERS' EQUITY
Other Liabilities	[9]	11,890		19,921
Basis differentials		(95,521)		(98,980)
Platform 16
LIABILITIES AND MEMBERS'/PARTNERS' EQUITY
Basis differentials		(143,052)		7,108
Carying value of the Company's investment in unconsolidated joint ventures	[9]	45,564		$ 158,109
Impairment loss on investment		155,200
Platform 16 | Unconsolidated Joint Ventures [Member]
LIABILITIES AND MEMBERS'/PARTNERS' EQUITY
Impairment loss on investment		$ 155,200

[1] See Note 4.

[2] At December 31, 2022, this amount included right of use assets - finance leases totaling approximately $248.9 million. At December 31, 2023 and December 31, 2022, this amount included right of use assets - operating leases totaling approximately $20.1 million and $21.2 million, respectively.

[3] At December 31, 2023, this amount included sales-type lease receivable, net totaling approximately $13.9 million.

[4] At December 31, 2022, this amount included lease liabilities - finance leases totaling approximately $382.2 million. At December 31, 2023 and December 31, 2022, 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. During the year ended December 31, 2023, the Company recognized an other-than-temporary impairment loss on its investments in Platform 16, 360 Park Avenue South, 200 Fifth Avenue and Safeco Plaza of approximately $155.2 million, $54.0 million, $33.4 million and $29.9 million, respectively, as well as a $35.8 million gain on investment related to Metropolitan Square, as described below in this Note 6. 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: December 31, 2023December 31, 2022Property(in thousands)Colorado Center$298,906 $301,820 200 Fifth Avenue58,308 94,497 Gateway Commons48,971 47,808 Safeco Plaza(29,678)(15)360 Park Avenue South(116,534)3,798 Dock 72(95,521)(98,980)Platform 16(143,052)7,108  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 $39.9 million and $85.4 million at December 31, 2023 and December 31, 2022, respectively, are reflected within Other Liabilities in the Company’s Consolidated Balance Sheets.

[7] During the year ended December 31, 2023, the Company recognized an other-than-temporary impairment loss on its investments in Platform 16, 360 Park Avenue South, 200 Fifth Avenue and Safeco Plaza of approximately $155.2 million, $54.0 million, $33.4 million and $29.9 million, respectively, as described below in this Note 6. During the year ended December 31, 2022, the Company recognized an other-than-temporary impairment loss on its investment in the unconsolidated joint venture that owns Dock 72 in Brooklyn, New York totaling approximately $50.7 million.

[8] During the year ended December 31, 2023, the Company completed a restructuring of its ownership in Metropolitan Square, as described below in this Note 6.

[9] Investments with deficit balances aggregating approximately $39.9 million and $85.4 million at December 31, 2023 and December 31, 2022, respectively, are included within Other Liabilities in the Company’s Consolidated Balance Sheets.