Mortgages and Other Loans Payable - Schedule of Mortgages and Other Loans Payable (Details) - USD ($) $ in Thousands	Sep. 30, 2024	Dec. 31, 2023
Debt Instrument [Line Items]
Total fixed rate debt	$ 1,587,898	$ 1,387,386
Total floating rate debt	60,900	110,000
Total mortgages and other loans payable	1,648,798	1,497,386
Deferred financing costs, net of amortization	(4,806)	(6,067)
Total mortgages and other loans payable, net	1,643,992	1,491,319
420 Lexington Ave
Debt Instrument [Line Items]
Total fixed rate debt	272,750	277,238
10 East 53rd Street
Debt Instrument [Line Items]
Total fixed rate debt	205,000	0
100 Church Street
Debt Instrument [Line Items]
Total fixed rate debt	370,000	370,000
7 Dey / 185 Broadway
Debt Instrument [Line Items]
Total fixed rate debt	190,148	190,148
Landmark Square
Debt Instrument [Line Items]
Total fixed rate debt	100,000	100,000
485 Lexington Avenue
Debt Instrument [Line Items]
Total fixed rate debt	450,000	450,000
690 Madison Avenue
Debt Instrument [Line Items]
Total floating rate debt	60,900	60,000
719 Seventh Avenue
Debt Instrument [Line Items]
Total floating rate debt	$ 0	$ 50,000
Weighted Average | 420 Lexington Ave
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)	3.99%
Weighted Average | 10 East 53rd Street
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)	5.45%
Weighted Average | 100 Church Street
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)	5.89%
Weighted Average | 7 Dey / 185 Broadway
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)	6.65%
Weighted Average | Landmark Square
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)	4.90%
Weighted Average | 485 Lexington Avenue
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)	4.25%
Weighted Average | 690 Madison Avenue
Debt Instrument [Line Items]
Interest rate, floating rate debt (as a percent)	0.50%
Weighted Average | 719 Seventh Avenue
Debt Instrument [Line Items]
Interest rate, floating rate debt (as a percent)