Mortgages and Other Loans Payable (Details)	12 Months Ended
	Dec. 31, 2022 USD ($) extension	Dec. 31, 2021 USD ($)	Apr. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)
Debt Instrument [Line Items]
Total fixed rate debt	$ 3,165,814,000	$ 1,073,409,000
Total floating rate debt	70,148,000	361,051,000
Total fixed rate and floating rate debt	3,235,962,000	1,434,460,000
Mortgages reclassed to liabilities related to assets held for sale	0	(34,537,000)
Total mortgages and other loans payable	3,235,962,000	1,399,923,000
Deferred financing costs, net of amortization	(8,399,000)	(5,537,000)
Total mortgages and other loans payable	3,227,563,000	1,394,386,000
Book value of collateral	3,800,000,000	2,100,000,000
719 Seventh Avenue
Debt Instrument [Line Items]
Total fixed rate debt	50,000,000	0
Total floating rate debt	0	50,000,000
7 Dey/185 Broadway
Debt Instrument [Line Items]
Total fixed rate debt	200,000,000	0
Total floating rate debt	10,148,000	198,169,000
420 Lexington Avenue
Debt Instrument [Line Items]
Total fixed rate debt	283,064,000	288,660,000
100 Church Street
Debt Instrument [Line Items]
Total fixed rate debt	370,000,000	200,212,000
Landmark Square
Debt Instrument [Line Items]
Total fixed rate debt	100,000,000	100,000,000
485 Lexington Avenue
Debt Instrument [Line Items]
Total fixed rate debt	450,000,000	450,000,000
245 Park Avenue
Debt Instrument [Line Items]
Total fixed rate debt	1,712,750,000	0
1080 Amsterdam Avenue
Debt Instrument [Line Items]
Total fixed rate debt	0	34,537,000
690 Madison Avenue
Debt Instrument [Line Items]
Total floating rate debt	60,000,000	60,000,000
609 Fifth Avenue
Debt Instrument [Line Items]
Total floating rate debt	$ 0	$ 52,882,000
Weighted Average | 719 Seventh Avenue
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)	4.70%
Weighted Average | 7 Dey/185 Broadway
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)	7.59%
Interest rate, floating rate debt (as a percent)	2.85%
Weighted Average | 420 Lexington Avenue
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)	3.99%
Weighted Average | 100 Church Street
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)	5.89%
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 | 245 Park Avenue
Debt Instrument [Line Items]
Interest rate, fixed rate debt (as a percent)	4.22%
Weighted Average | 690 Madison Avenue
Debt Instrument [Line Items]
Interest rate, floating rate debt (as a percent)	1.50%
2017 Master Repurchase Agreement 2017
Debt Instrument [Line Items]
Maximum facility capacity			$ 400,000,000.0	$ 300,000,000
Construction Loans | 185 Broadway
Debt Instrument [Line Items]
Maximum facility capacity	$ 225,000,000
Term	3 years
Number of extension options | extension	2
Period of extension option	1 year