Fair Value Measurements (Schedule of Derivative Instruments) (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Jan. 31, 2024	Dec. 31, 2023
Derivative [Line Items]
Long term debt	$ 2,564,289		$ 2,563,432
Matures in May 2028 | 555 California Street | Office
Derivative [Line Items]
Equity method ownership percentage	70.00%		70.00%
Debt instrument, amount	$ 1,200,000		$ 1,200,000
Designated as Hedging Instrument | Interest rate swaps
Derivative [Line Items]
Derivative, Average Fixed Interest Rate	1.29%
Designated as Hedging Instrument | Interest Rate Cap
Derivative [Line Items]
Fair Value Asset	$ 168,853		138,772
Fair Value Liability			7,239
Designated as Hedging Instrument | 555 California Street Mortgage Loan, In-Place Swap | Interest rate swaps
Derivative [Line Items]
Notional amount and swapped balance	$ 840,000
All-In Swapped Rate	2.29%
Fair Value Asset	$ 5,187		15,494
Fair Value Liability			0
Designated as Hedging Instrument | 555 California Street Mortgage Loan, Forward Swap | Interest rate swaps
Derivative [Line Items]
Notional amount and swapped balance	$ 840,000
All-In Swapped Rate	6.03%
Fair Value Asset	$ 6,108		0
Fair Value Liability			6,091
Designated as Hedging Instrument | 770 Broadway mortgage loan | Interest rate swaps
Derivative [Line Items]
Notional amount and swapped balance	$ 700,000
All-In Swapped Rate	4.98%
Fair Value Asset	$ 29,953		20,306
Fair Value Liability			0
Designated as Hedging Instrument | PENN 11 mortgage loan | Interest rate swaps
Derivative [Line Items]
Notional amount and swapped balance	$ 500,000
All-In Swapped Rate	6.28%
Fair Value Asset	$ 3,247		4,702
Fair Value Liability			1,148
Designated as Hedging Instrument | Unsecured revolving credit facility | Interest rate swaps
Derivative [Line Items]
Notional amount and swapped balance	$ 575,000
All-In Swapped Rate	3.87%
Fair Value Asset	$ 25,251		17,064
Fair Value Liability			0
Designated as Hedging Instrument | Unsecured term loan | Interest rate swaps
Derivative [Line Items]
Notional amount and swapped balance	$ 700,000
All-In Swapped Rate	4.52%
Fair Value Asset	$ 18,577		11,089
Fair Value Liability			0
Designated as Hedging Instrument | 100 West 33rd Street mortgage loan | Interest rate swaps
Derivative [Line Items]
Notional amount and swapped balance	$ 480,000
All-In Swapped Rate	5.06%
Fair Value Asset	$ 10,826		3,550
Fair Value Liability			0
Designated as Hedging Instrument | 888 Seventh Avenue mortgage loan | Interest rate swaps
Derivative [Line Items]
Notional amount and swapped balance	$ 200,000
All-In Swapped Rate	4.76%
Fair Value Asset	$ 7,299		4,340
Fair Value Liability			0
Long term debt	$ 59,800
Rate	7.13%
Designated as Hedging Instrument | 888 Seventh Avenue mortgage loan | Interest rate swaps | SOFR
Derivative [Line Items]
Derivative, basis spread on variable rate	1.80%
Designated as Hedging Instrument | 4 Union Square South mortgage loan | Interest rate swaps
Derivative [Line Items]
Notional amount and swapped balance	$ 97,750
All-In Swapped Rate	3.74%
Fair Value Asset	$ 2,048		2,327
Fair Value Liability			0
Long term debt	$ 22,250
Rate	6.83%
Designated as Hedging Instrument | 4 Union Square South mortgage loan | Interest rate swaps | SOFR
Derivative [Line Items]
Derivative, basis spread on variable rate	1.50%
Designated as Hedging Instrument | 1290 Avenue of the Americas mortgage loan | Interest Rate Cap
Derivative [Line Items]
Notional amount and swapped balance	$ 950,000
Fair Value Asset	54,223		53,784
Fair Value Liability			0
Premium paid in connection with the purchase of cap arrangement	63,100
Designated as Hedging Instrument | 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 Hedging Instrument | 1290 Avenue of the Americas mortgage loan | Interest Rate Cap | SOFR
Derivative [Line Items]
Cap strike rate	1.00%
Designated as Hedging Instrument | One Park Avenue mortgage loan | Interest Rate Cap
Derivative [Line Items]
Notional amount and swapped balance	$ 525,000
Fair Value Asset	$ 5,464		5,297
Fair Value Liability			0
Designated as Hedging Instrument | One Park Avenue mortgage loan | Interest Rate Cap | SOFR
Derivative [Line Items]
Cap strike rate	3.89%
Designated as Hedging Instrument | Various mortgage loans | Interest Rate Cap
Derivative [Line Items]
Fair Value Asset	$ 670		819
Fair Value Liability			$ 0
Designated as Hedging Instrument | PENN 11 mortgage loan, Forward Swap | Interest rate swaps
Derivative [Line Items]
Notional amount and swapped balance		$ 250,000
Designated as Hedging Instrument | PENN 11 mortgage loan, In-Place Swap | Interest rate swaps
Derivative [Line Items]
All-In Swapped Rate		6.28%
Long term debt		$ 500,000
Designated as Hedging Instrument | Unsecured Term Loan Expiring July 2025 | Interest rate swaps
Derivative [Line Items]
Notional amount and swapped balance	$ 700,000
All-In Swapped Rate	4.52%
Unswapped Balance	$ 100,000
Designated as Hedging Instrument | Unsecured Term Loan Expiring October 2026 | Interest rate swaps
Derivative [Line Items]
Notional amount and swapped balance	$ 550,000
All-In Swapped Rate	4.35%
Unswapped Balance	$ 250,000
Designated as Hedging Instrument | Unsecured Term Loan Expiring August 2027 | Interest rate swaps
Derivative [Line Items]
Notional amount and swapped balance	$ 50,000
All-In Swapped Rate	4.03%
Unswapped Balance	$ 750,000