Revenue Recognition (Schedule of Revenues by Segment ) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Disaggregation of Revenue [Line Items]
Operating Lease, Lease Income, Statement of Income or Comprehensive Income [Extensible Enumeration]	Total revenues	Total revenues	Total revenues	Total revenues
Lease income	$ 379,247	$ 403,835	$ 754,846	$ 785,712
Total revenues	450,266	472,359	886,641	918,282
Loss contingency, damages awarded, value		21,350		21,350
Non-controlling Interests in Consolidated Subsidiaries
Disaggregation of Revenue [Line Items]
Loss contingency, damages awarded, value		6,405		6,405
Rental revenues
Disaggregation of Revenue [Line Items]
Total revenues	393,595	418,834	782,873	815,627
Lease revenues
Disaggregation of Revenue [Line Items]
Lease income	379,247	403,835	754,846	785,712
Property rentals
Disaggregation of Revenue [Line Items]
Lease income	372,186	397,053	742,069	773,882
Trade shows
Disaggregation of Revenue [Line Items]
Lease income	7,061	6,782	12,777	11,830
Tenant services
Disaggregation of Revenue [Line Items]
Revenue	9,604	9,804	18,632	19,573
Parking revenues
Disaggregation of Revenue [Line Items]
Revenue	4,744	5,195	9,395	10,342
Fee and other income
Disaggregation of Revenue [Line Items]
Revenue	56,671	53,525	103,768	102,655
Total revenues	56,671	53,525	103,768	102,655
BMS cleaning fees
Disaggregation of Revenue [Line Items]
Revenue	38,465	35,146	74,245	70,474
Management and leasing fees
Disaggregation of Revenue [Line Items]
Revenue	6,709	3,658	9,320	6,707
Other income
Disaggregation of Revenue [Line Items]
Revenue	11,497	14,721	20,203	25,474
New York
Disaggregation of Revenue [Line Items]
Total revenues	367,578	362,471	725,812	726,285
New York | Rental revenues
Disaggregation of Revenue [Line Items]
Total revenues	312,903	316,702	624,638	636,218
New York | Lease revenues
Disaggregation of Revenue [Line Items]
Lease income	302,780	305,182	604,311	612,904
New York | Property rentals
Disaggregation of Revenue [Line Items]
Lease income	302,780	305,182	604,311	612,904
New York | Trade shows
Disaggregation of Revenue [Line Items]
Lease income	0	0	0	0
New York | Tenant services
Disaggregation of Revenue [Line Items]
Revenue	6,373	7,325	12,920	14,907
New York | Parking revenues
Disaggregation of Revenue [Line Items]
Revenue	3,750	4,195	7,407	8,407
New York | Fee and other income
Disaggregation of Revenue [Line Items]
Revenue	54,675	45,769	101,174	90,067
New York | BMS cleaning fees
Disaggregation of Revenue [Line Items]
Revenue	40,689	37,754	79,329	75,432
New York | Management and leasing fees
Disaggregation of Revenue [Line Items]
Revenue	6,911	3,761	9,623	6,934
New York | Other income
Disaggregation of Revenue [Line Items]
Revenue	7,075	4,254	12,222	7,701
Other
Disaggregation of Revenue [Line Items]
Total revenues	82,688	109,888	160,829	191,997
Other | Rental revenues
Disaggregation of Revenue [Line Items]
Total revenues	80,692	102,132	158,235	179,409
Other | Lease revenues
Disaggregation of Revenue [Line Items]
Lease income	76,467	98,653	150,535	172,808
Other | Property rentals
Disaggregation of Revenue [Line Items]
Lease income	69,406	91,871	137,758	160,978
Other | Trade shows
Disaggregation of Revenue [Line Items]
Lease income	7,061	6,782	12,777	11,830
Other | Tenant services
Disaggregation of Revenue [Line Items]
Revenue	3,231	2,479	5,712	4,666
Other | Parking revenues
Disaggregation of Revenue [Line Items]
Revenue	994	1,000	1,988	1,935
Other | Fee and other income
Disaggregation of Revenue [Line Items]
Revenue	1,996	7,756	2,594	12,588
Other | BMS cleaning fees
Disaggregation of Revenue [Line Items]
Revenue	(2,224)	(2,608)	(5,084)	(4,958)
Other | Management and leasing fees
Disaggregation of Revenue [Line Items]
Revenue	(202)	(103)	(303)	(227)
Other | Other income
Disaggregation of Revenue [Line Items]
Revenue	$ 4,422	$ 10,467	$ 7,981	$ 17,773