Revenue Recognition (Revenues by Segment) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Disaggregation of Revenue [Line Items]
Lease income	$ 383,031	$ 332,058
Total revenues	442,130	379,977
New York
Disaggregation of Revenue [Line Items]
Total revenues	358,548	303,971
Other
Disaggregation of Revenue [Line Items]
Total revenues	83,582	76,006
Rental revenues
Disaggregation of Revenue [Line Items]
Total revenues	397,283	339,317
Rental revenues | New York
Disaggregation of Revenue [Line Items]
Total revenues	318,845	266,700
Rental revenues | Other
Disaggregation of Revenue [Line Items]
Total revenues	78,438	72,617
Lease revenues
Disaggregation of Revenue [Line Items]
Lease income	383,031	332,058
Lease revenues | New York
Disaggregation of Revenue [Line Items]
Lease income	307,723	261,691
Lease revenues | Other
Disaggregation of Revenue [Line Items]
Lease income	75,308	70,367
Property rentals
Disaggregation of Revenue [Line Items]
Lease income	377,887	332,058
Property rentals | New York
Disaggregation of Revenue [Line Items]
Lease income	307,723	261,691
Property rentals | Other
Disaggregation of Revenue [Line Items]
Lease income	70,164	70,367
Trade shows
Disaggregation of Revenue [Line Items]
Lease income	5,144	0
Trade shows | New York
Disaggregation of Revenue [Line Items]
Lease income	0	0
Trade shows | Other
Disaggregation of Revenue [Line Items]
Lease income	5,144	0
Tenant services
Disaggregation of Revenue [Line Items]
Revenue	9,889	7,259
Tenant services | New York
Disaggregation of Revenue [Line Items]
Revenue	7,411	5,009
Tenant services | Other
Disaggregation of Revenue [Line Items]
Revenue	2,478	2,250
Parking revenues
Disaggregation of Revenue [Line Items]
Revenue	4,363
Parking revenues | New York
Disaggregation of Revenue [Line Items]
Revenue	3,711
Parking revenues | Other
Disaggregation of Revenue [Line Items]
Revenue	652
Fee and other income
Disaggregation of Revenue [Line Items]
Revenue	44,847	40,660
Total revenues	44,847	40,660
Fee and other income | New York
Disaggregation of Revenue [Line Items]
Revenue	39,703	37,271
Fee and other income | Other
Disaggregation of Revenue [Line Items]
Revenue	5,144	3,389
BMS cleaning fees
Disaggregation of Revenue [Line Items]
Revenue	32,691	28,477
BMS cleaning fees | New York
Disaggregation of Revenue [Line Items]
Revenue	34,711	29,948
BMS cleaning fees | Other
Disaggregation of Revenue [Line Items]
Revenue	(2,020)	(1,471)
Management and leasing fees
Disaggregation of Revenue [Line Items]
Revenue	2,769	5,369
Management and leasing fees | New York
Disaggregation of Revenue [Line Items]
Revenue	2,967	5,522
Management and leasing fees | Other
Disaggregation of Revenue [Line Items]
Revenue	(198)	(153)
Other income
Disaggregation of Revenue [Line Items]
Revenue	9,387	6,814
Other income | New York
Disaggregation of Revenue [Line Items]
Revenue	2,025	1,801
Other income | Other
Disaggregation of Revenue [Line Items]
Revenue	$ 7,362	$ 5,013