Revenue Recognition (Schedule of Revenues by Segment) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Disaggregation of Revenue [Line Items]
Operating Lease, Lease Income, Statement of Income or Comprehensive Income [Extensible Enumeration]	Total revenues	Total revenues
Lease income	$ 388,950	$ 375,599
Total revenues	461,579	436,375
Rental revenues
Disaggregation of Revenue [Line Items]
Total revenues	404,755	389,278
Lease revenues
Disaggregation of Revenue [Line Items]
Lease income	388,950	375,599
Property rentals
Disaggregation of Revenue [Line Items]
Lease income	382,514	369,883
Trade shows
Disaggregation of Revenue [Line Items]
Lease income	6,436	5,716
Tenant services
Disaggregation of Revenue [Line Items]
Revenue	10,935	9,028
Parking revenues
Disaggregation of Revenue [Line Items]
Revenue	4,870	4,651
Fee and other income
Disaggregation of Revenue [Line Items]
Revenue	56,824	47,097
Total revenues	56,824	47,097
BMS cleaning fees
Disaggregation of Revenue [Line Items]
Revenue	36,476	35,780
Management and leasing fees
Disaggregation of Revenue [Line Items]
Revenue	3,030	2,611
Other income
Disaggregation of Revenue [Line Items]
Revenue	17,318	8,706
New York
Disaggregation of Revenue [Line Items]
Total revenues	376,206	358,234
New York | Rental revenues
Disaggregation of Revenue [Line Items]
Total revenues	324,299	311,735
New York | Lease revenues
Disaggregation of Revenue [Line Items]
Lease income	312,302	301,531
New York | Property rentals
Disaggregation of Revenue [Line Items]
Lease income	312,302	301,531
New York | Trade shows
Disaggregation of Revenue [Line Items]
Lease income	0	0
New York | Tenant services
Disaggregation of Revenue [Line Items]
Revenue	8,173	6,547
New York | Parking revenues
Disaggregation of Revenue [Line Items]
Revenue	3,824	3,657
New York | Fee and other income
Disaggregation of Revenue [Line Items]
Revenue	51,907	46,499
New York | BMS cleaning fees
Disaggregation of Revenue [Line Items]
Revenue	38,497	38,640
New York | Management and leasing fees
Disaggregation of Revenue [Line Items]
Revenue	3,205	2,712
New York | Other income
Disaggregation of Revenue [Line Items]
Revenue	10,205	5,147
Other
Disaggregation of Revenue [Line Items]
Total revenues	85,373	78,141
Other | Rental revenues
Disaggregation of Revenue [Line Items]
Total revenues	80,456	77,543
Other | Lease revenues
Disaggregation of Revenue [Line Items]
Lease income	76,648	74,068
Other | Property rentals
Disaggregation of Revenue [Line Items]
Lease income	70,212	68,352
Other | Trade shows
Disaggregation of Revenue [Line Items]
Lease income	6,436	5,716
Other | Tenant services
Disaggregation of Revenue [Line Items]
Revenue	2,762	2,481
Other | Parking revenues
Disaggregation of Revenue [Line Items]
Revenue	1,046	994
Other | Fee and other income
Disaggregation of Revenue [Line Items]
Revenue	4,917	598
Other | BMS cleaning fees
Disaggregation of Revenue [Line Items]
Revenue	(2,021)	(2,860)
Other | Management and leasing fees
Disaggregation of Revenue [Line Items]
Revenue	(175)	(101)
Other | Other income
Disaggregation of Revenue [Line Items]
Revenue	$ 7,113	$ 3,559