Mortgages and Other Loans Payable - Schedule of Mortgages and Other Loans Payable (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Debt Instrument [Line Items]
Total fixed rate debt	$ 1,590,885		$ 1,387,386
Total floating rate debt	110,493		110,000
Total mortgages and other loans payable	1,701,378		1,497,386
Deferred financing costs, net of amortization	(6,215)		(6,067)
Total mortgages and other loans payable, net	1,695,163		1,491,319
Repayments of mortgages	1,501	$ 1,473
420 Lexington Ave
Debt Instrument [Line Items]
Total fixed rate debt	275,737		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	60,493		60,000
719 Seventh Avenue
Debt Instrument [Line Items]
Total floating rate debt	50,000		$ 50,000
Total mortgages and other loans payable, net	50,000
Repayments of mortgages	$ 32,000
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)	1.31%