Fair Value Measurements (Schedule of Derivative Instruments) (Details) - USD ($) $ in Thousands	Jan. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Derivative [Line Items]
Long term debt		$ 2,563,432	$ 2,560,025
Matures in May 2028 | 555 California Street, California | Office Building
Derivative [Line Items]
Ownership interest		70.00%	70.00%
Debt instrument, amount		$ 1,200,000	$ 1,200,000
Designated as a Hedge
Derivative [Line Items]
Fair Value Asset		138,772	183,804
Fair Value Liability		7,239
Designated as a Hedge | 555 California Street mortgage loan, In-place swap | Interest Rate Swap
Derivative [Line Items]
Notional Amount		$ 840,000
All-In Swapped Rate		2.29%
Fair Value Asset		$ 15,494	49,888
Fair Value Liability		0
Designated as a Hedge | 555 California Street mortgage loan, Forward swap | Interest Rate Swap
Derivative [Line Items]
Notional Amount		$ 840,000
All-In Swapped Rate		6.03%
Fair Value Asset		$ 0	0
Fair Value Liability		6,091
Designated as a Hedge | 770 Broadway mortgage loan | Interest Rate Swap
Derivative [Line Items]
Notional Amount		$ 700,000
All-In Swapped Rate		4.98%
Fair Value Asset		$ 20,306	29,226
Fair Value Liability		0
Designated as a Hedge | PENN 11 mortgage loan, In-Place Swap | Interest Rate Swap
Derivative [Line Items]
Notional Amount		$ 500,000
All-In Swapped Rate		2.22%
Fair Value Asset		$ 4,702	26,587
Fair Value Liability		0
Long term debt		500
Designated as a Hedge | PENN 11 mortgage loan, In-Place Swap | Interest Rate Swap | Subsequent Event
Derivative [Line Items]
All-In Swapped Rate	6.28%
Designated as a Hedge | PENN 11 mortgage loan, Forward Swap | Interest Rate Swap
Derivative [Line Items]
Notional Amount		$ 250,000
All-In Swapped Rate		6.34%
Fair Value Asset		$ 0	0
Fair Value Liability		1,148
Designated as a Hedge | PENN 11 mortgage loan, Forward Swap | Interest Rate Swap | Subsequent Event
Derivative [Line Items]
Notional Amount	$ 250
Designated as a Hedge | Unsecured revolving credit facility | Interest Rate Swap
Derivative [Line Items]
Notional Amount		$ 575,000
All-In Swapped Rate		3.87%
Fair Value Asset		$ 17,064	24,457
Fair Value Liability		0
Designated as a Hedge | Unsecured term loan | Interest Rate Swap
Derivative [Line Items]
Notional Amount		$ 700,000
All-In Swapped Rate		4.52%
Fair Value Asset		$ 11,089	21,024
Fair Value Liability		0
Designated as a Hedge | Unsecured term loan | Notional swap expired October 2023
Derivative [Line Items]
Notional Amount			100
Designated as a Hedge | 100 West 33rd Street mortgage loan | Interest Rate Swap
Derivative [Line Items]
Notional Amount		$ 480,000
All-In Swapped Rate		5.06%
Fair Value Asset		$ 3,550	6,886
Fair Value Liability		0
Designated as a Hedge | 888 Seventh Avenue mortgage loan | Interest Rate Swap
Derivative [Line Items]
Notional Amount		$ 200,000
All-In Swapped Rate		4.76%
Fair Value Asset		$ 4,340	6,544
Fair Value Liability		0
Long term debt		$ 59,800
Basis spread		7.14%
Designated as a Hedge | 888 Seventh Avenue mortgage loan | Interest Rate Swap | SOFR
Derivative [Line Items]
Derivative, basis spread on variable rate		1.80%
Designated as a Hedge | 4 Union Square South mortgage loan | Interest Rate Swap
Derivative [Line Items]
Notional Amount		$ 98,200
All-In Swapped Rate		3.74%
Fair Value Asset		$ 2,327	4,050
Fair Value Liability		0
Long term debt		$ 21,800
Basis spread		6.84%
Designated as a Hedge | 4 Union Square South mortgage loan | Interest Rate Swap | SOFR
Derivative [Line Items]
Derivative, basis spread on variable rate		1.50%
Designated as a Hedge | 1290 Avenue of the Americas mortgage loan | Interest Rate Cap
Derivative [Line Items]
Notional Amount		$ 950,000
Fair Value Asset		53,784	7,590
Fair Value Liability		0
Up-front payment		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]
Up-front payment		$ 18,930
Designated as a Hedge | 1290 Avenue of the Americas mortgage loan | Interest Rate Cap | SOFR
Derivative [Line Items]
Cap strike rate		1.00%
Designated as a Hedge | One Park Avenue mortgage loan | Interest Rate Cap
Derivative [Line Items]
Notional Amount		$ 525,000
Fair Value Asset		5,297	5,472
Fair Value Liability		$ 0
Designated as a Hedge | One Park Avenue mortgage loan | Interest Rate Cap | SOFR
Derivative [Line Items]
Cap strike rate		3.89%
Designated as a Hedge | One Park Avenue mortgage loan | Forward Cap | SOFR
Derivative [Line Items]
Cap strike rate		3.89%
Designated as a Hedge | Various mortgage loans | Interest Rate Cap
Derivative [Line Items]
Fair Value Asset		$ 819	$ 2,080
Fair Value Liability		0
Designated as a Hedge | Unsecured Term Loan Expiring October 2026 | Interest Rate Swap
Derivative [Line Items]
Notional Amount		$ 550,000
All-In Swapped Rate		4.35%
Derivative liability, notional amount		$ 250,000
Designated as a Hedge | Unsecured Term Loan Expiring July 2025 | Interest Rate Swap
Derivative [Line Items]
Notional Amount		$ 700,000
All-In Swapped Rate		4.52%
Derivative liability, notional amount		$ 100,000
Designated as a Hedge | Unsecured Term Loan Expiring August 2027 | Interest Rate Swap
Derivative [Line Items]
Notional Amount		$ 50,000
All-In Swapped Rate		4.03%
Derivative liability, notional amount		$ 750,000