Fair Value Measurements (Schedule of Derivative Instruments) (Details) - USD ($) $ in Thousands	Dec. 31, 2024	Jan. 31, 2024	Dec. 31, 2023
Derivative [Line Items]
Long term debt	$ 2,566,862		$ 2,563,432
Matures in May 2028 | 555 California Street, California | Office Building
Derivative [Line Items]
Equity method ownership percentage	70.00%		70.00%
Debt amount	$ 1,200,000		$ 1,200,000
Designated as a Hedge
Derivative [Line Items]
Fair Value Asset	88,982		138,772
Fair Value Liability	1,023		7,239
Designated as a Hedge | 555 California Street mortgage loan | Interest Rate Swap
Derivative [Line Items]
Notional amount and swapped balance	$ 840,000
All-In Swapped Rate	6.03%
Fair Value Asset	$ 765		15,494
Fair Value Liability	0		6,091
Designated as a Hedge | 770 Broadway mortgage loan | Interest Rate Swap
Derivative [Line Items]
Notional amount and swapped balance	$ 700,000
All-In Swapped Rate	4.98%
Fair Value Asset	$ 21,332		20,306
Fair Value Liability	0		0
Designated as a Hedge | PENN 11 mortgage loan | Interest Rate Swap
Derivative [Line Items]
Notional amount and swapped balance	$ 500,000
All-In Swapped Rate	6.28%
Fair Value Asset	$ 17		4,702
Fair Value Liability	282		1,148
Designated as a Hedge | Unsecured revolving credit facility | Interest Rate Swap
Derivative [Line Items]
Notional amount and swapped balance	$ 575,000
All-In Swapped Rate	3.88%
Fair Value Asset	$ 18,510		17,064
Fair Value Liability	0		0
Designated as a Hedge | Unsecured term loan | Interest Rate Swap
Derivative [Line Items]
Notional amount and swapped balance	$ 700,000
All-In Swapped Rate	4.53%
Fair Value Asset	$ 10,128		11,089
Fair Value Liability	0		0
Designated as a Hedge | 100 West 33rd Street mortgage loan | Interest Rate Swap
Derivative [Line Items]
Notional amount and swapped balance	$ 480,000
All-In Swapped Rate	5.26%
Fair Value Asset	$ 6,808		3,550
Fair Value Liability	0		0
Designated as a Hedge | 888 Seventh Avenue mortgage loan | Interest Rate Swap
Derivative [Line Items]
Notional amount and swapped balance	$ 200,000
All-In Swapped Rate	4.76%
Fair Value Asset	$ 5,249		4,340
Fair Value Liability	0		0
Long term debt	$ 58,057
Derivative, basis spread on variable rate	1.80%
Variable interest rate	6.35%
Designated as a Hedge | 4 Union Square South mortgage loan | Interest Rate Swap
Derivative [Line Items]
Notional amount and swapped balance	$ 96,400
All-In Swapped Rate	3.74%
Fair Value Asset	$ 12		2,327
Fair Value Liability	0		0
Long term debt	$ 23,600
Derivative, basis spread on variable rate	1.50%
Variable interest rate	6.05%
Designated as a Hedge | 435 Seventh Avenue mortgage loan | Interest Rate Swap
Derivative [Line Items]
Notional amount and swapped balance	$ 75,000
All-In Swapped Rate	6.96%
Fair Value Asset	$ 0		0
Fair Value Liability	741		0
Designated as a Hedge | 1290 Avenue of the Americas mortgage loan | Interest Rate Cap
Derivative [Line Items]
Notional amount and swapped balance	950,000
Fair Value Asset	25,673		53,784
Fair Value Liability	$ 0		0
Cap strike rate	1.00%
Premium paid in connection with the purchase of cap arrangement			63,100
Designated as a Hedge | 1290 Avenue of the Americas mortgage loan | Interest Rate Cap | Non- controlling Interests in Consolidated Subsidiaries
Derivative [Line Items]
Premium paid in connection with the purchase of cap arrangement			18,930
Designated as a Hedge | One Park Avenue mortgage loan | Interest Rate Cap
Derivative [Line Items]
Notional amount and swapped balance	$ 525,000
Fair Value Asset	464		5,297
Fair Value Liability	$ 0		0
Cap strike rate	3.89%
Designated as a Hedge | Various mortgage loans | Interest Rate Cap
Derivative [Line Items]
Fair Value Asset	$ 24		819
Fair Value Liability	0		$ 0
Designated as a Hedge | PENN 11 mortgage loan, Interest Rate Swap | Interest Rate Swap
Derivative [Line Items]
Notional amount and swapped balance		$ 250,000
Designated as a Hedge | PENN 11 mortgage loan, In-Place Swap | Interest Rate Swap
Derivative [Line Items]
All-In Swapped Rate		6.28%
Long term debt		$ 500,000
Designated as a Hedge | Unsecured Term Loan Expiring July 2025 | Interest Rate Swap
Derivative [Line Items]
Notional amount and swapped balance	$ 700,000
All-In Swapped Rate	4.53%
Unswapped Balance	$ 100,000
Designated as a Hedge | Unsecured Term Loan July 2025 through October 2026 | Interest Rate Swap
Derivative [Line Items]
Notional amount and swapped balance	$ 550,000
All-In Swapped Rate	4.36%
Unswapped Balance	$ 250,000
Designated as a Hedge | Unsecured Term Loan October 2026 through August 2027 | Interest Rate Swap
Derivative [Line Items]
Notional amount and swapped balance	$ 50,000
All-In Swapped Rate	4.04%
Unswapped Balance	$ 750,000