Fair Value of Financial Instruments - Financial Instruments Not Carried at Fair Value (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Impairment of real estate investments	$ 112,541	$ 66,565	$ 0
1140 Avenues of the Americas
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Impairment of real estate investments	25,800	66,100
Mortgages | Significant Unobservable Inputs | Gross Principal Balance
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Mortgage notes payable	350,000	399,500
Mortgages | Significant Unobservable Inputs | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Mortgage notes payable	287,460	348,839
Mortgages | Mortgage note payable - 9 Times Square | Significant Unobservable Inputs | Gross Principal Balance
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Mortgage notes payable	0	49,500
Mortgages | Mortgage note payable - 9 Times Square | Significant Unobservable Inputs | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Mortgage notes payable	0	49,265
Mortgages | Mortgage note payable - 1140 Avenue of the Americas | Significant Unobservable Inputs | Gross Principal Balance
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Mortgage notes payable	99,000	99,000
Mortgages | Mortgage note payable - 1140 Avenue of the Americas | Significant Unobservable Inputs | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Mortgage notes payable	69,238	69,619
Mortgages | Mortgage note payable - 123 William Street | Significant Unobservable Inputs | Gross Principal Balance
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Mortgage notes payable	140,000	140,000
Mortgages | Mortgage note payable - 123 William Street | Significant Unobservable Inputs | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Mortgage notes payable	132,474	130,463
Mortgages | Mortgage note payable — 400 E. 67th Street - Laurel Condominium / 200 Riverside Boulevard - ICON Garage (2) | Significant Unobservable Inputs | Gross Principal Balance
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Mortgage notes payable	50,000	50,000
Mortgages | Mortgage note payable — 400 E. 67th Street - Laurel Condominium / 200 Riverside Boulevard - ICON Garage (2) | Significant Unobservable Inputs | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Mortgage notes payable	31,671	45,442
Mortgages | Mortgage note payable — 8713 Fifth Avenue | Significant Unobservable Inputs | Gross Principal Balance
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Mortgage notes payable	10,000	10,000
Mortgages | Mortgage note payable — 8713 Fifth Avenue | Significant Unobservable Inputs | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Mortgage notes payable	9,181	9,193
Mortgages | Mortgage note payable - 196 Orchard Street | Significant Unobservable Inputs | Gross Principal Balance
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Mortgage notes payable	51,000	51,000
Mortgages | Mortgage note payable - 196 Orchard Street | Significant Unobservable Inputs | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Mortgage notes payable	$ 44,896	$ 44,857