Revenue Recognition (Schedule of Revenues by Segment ) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 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	$ 369,692	$ 382,683	$ 1,124,538	$ 1,168,395
Total revenues	443,255	450,995	1,329,896	1,369,277
Tenant settlement		21,350		21,350
Non-controlling Interests in Consolidated Subsidiaries
Disaggregation of Revenue [Line Items]
Tenant settlement		6,405		6,405
Rental revenues
Disaggregation of Revenue [Line Items]
Total revenues	387,470	400,367	1,170,343	1,215,994
Lease revenues
Disaggregation of Revenue [Line Items]
Lease income	369,692	382,683	1,124,538	1,168,395
Property rentals
Disaggregation of Revenue [Line Items]
Lease income	362,903	376,505	1,104,972	1,150,387
Trade shows
Disaggregation of Revenue [Line Items]
Lease income	6,789	6,178	19,566	18,008
Tenant services
Disaggregation of Revenue [Line Items]
Revenue	13,190	12,793	31,822	32,366
Parking revenues
Disaggregation of Revenue [Line Items]
Revenue	4,588	4,891	13,983	15,233
Fee and other income
Disaggregation of Revenue [Line Items]
Revenue	55,785	50,628	159,553	153,283
Total revenues	55,785	50,628	159,553	153,283
BMS cleaning fees
Disaggregation of Revenue [Line Items]
Revenue	37,772	35,428	112,017	105,902
Management and leasing fees
Disaggregation of Revenue [Line Items]
Revenue	2,841	3,263	12,161	9,970
Other income
Disaggregation of Revenue [Line Items]
Revenue	15,172	11,937	35,375	37,411
New York
Disaggregation of Revenue [Line Items]
Total revenues	362,483	364,768	1,088,295	1,091,053
New York | Rental revenues
Disaggregation of Revenue [Line Items]
Total revenues	307,169	319,456	931,807	955,674
New York | Lease revenues
Disaggregation of Revenue [Line Items]
Lease income	294,258	306,717	898,569	919,621
New York | Property rentals
Disaggregation of Revenue [Line Items]
Lease income	294,258	306,717	898,569	919,621
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	9,300	8,789	22,220	23,696
New York | Parking revenues
Disaggregation of Revenue [Line Items]
Revenue	3,611	3,950	11,018	12,357
New York | Fee and other income
Disaggregation of Revenue [Line Items]
Revenue	55,314	45,312	156,488	135,379
New York | BMS cleaning fees
Disaggregation of Revenue [Line Items]
Revenue	41,007	37,999	120,336	113,431
New York | Management and leasing fees
Disaggregation of Revenue [Line Items]
Revenue	3,089	3,441	12,712	10,375
New York | Other income
Disaggregation of Revenue [Line Items]
Revenue	11,218	3,872	23,440	11,573
Other
Disaggregation of Revenue [Line Items]
Total revenues	80,772	86,227	241,601	278,224
Other | Rental revenues
Disaggregation of Revenue [Line Items]
Total revenues	80,301	80,911	238,536	260,320
Other | Lease revenues
Disaggregation of Revenue [Line Items]
Lease income	75,434	75,966	225,969	248,774
Other | Property rentals
Disaggregation of Revenue [Line Items]
Lease income	68,645	69,788	206,403	230,766
Other | Trade shows
Disaggregation of Revenue [Line Items]
Lease income	6,789	6,178	19,566	18,008
Other | Tenant services
Disaggregation of Revenue [Line Items]
Revenue	3,890	4,004	9,602	8,670
Other | Parking revenues
Disaggregation of Revenue [Line Items]
Revenue	977	941	2,965	2,876
Other | Fee and other income
Disaggregation of Revenue [Line Items]
Revenue	471	5,316	3,065	17,904
Other | BMS cleaning fees
Disaggregation of Revenue [Line Items]
Revenue	(3,235)	(2,571)	(8,319)	(7,529)
Other | Management and leasing fees
Disaggregation of Revenue [Line Items]
Revenue	(248)	(178)	(551)	(405)
Other | Other income
Disaggregation of Revenue [Line Items]
Revenue	$ 3,954	$ 8,065	$ 11,935	$ 25,838