Fair Value Measurements (Schedule of Derivative Instruments) (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Feb. 28, 2023	Dec. 31, 2022
Derivative [Line Items]
Long term debt	$ 2,561,717		$ 2,560,025
Non-controlling Interests in Consolidated Subsidiaries
Derivative [Line Items]
Rate (as percent)	30.00%
SOFR
Derivative [Line Items]
Rate (as percent)	1.00%
Matures in May 2028 | Five Five Five 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 Cap
Derivative [Line Items]
Derivative asset, fair value	242,379		183,804
Derivative liability, fair value	1,280
Designated as Hedging Instrument | 555 California Street Mortgage Loan, In-Place Swap | Interest rate swaps
Derivative [Line Items]
Derivative asset, notional amount	$ 840,000
Derivative, fixed interest rate	2.29%
Derivative asset, fair value	$ 36,414		49,888
Derivative liability, fair value	0
Designated as Hedging Instrument | 555 California Street Mortgage Loan, Forward Swap | Interest rate swaps
Derivative [Line Items]
Derivative asset, notional amount	$ 840,000
Derivative, fixed interest rate	6.03%
Derivative asset, fair value	$ 0		0
Derivative liability, fair value	1,280
Designated as Hedging Instrument | 770 Broadway mortgage loan | Interest rate swaps
Derivative [Line Items]
Derivative asset, notional amount	$ 700,000
Derivative, fixed interest rate	4.98%
Derivative asset, fair value	$ 33,320		29,226
Derivative liability, fair value	0
Designated as Hedging Instrument | PENN 11 mortgage loan | Interest rate swaps
Derivative [Line Items]
Derivative asset, notional amount	$ 500,000
Derivative, fixed interest rate	2.22%
Derivative asset, fair value	$ 17,471		26,587
Derivative liability, fair value	0
Designated as Hedging Instrument | Unsecured revolving credit facility | Interest rate swaps
Derivative [Line Items]
Derivative asset, notional amount	$ 575,000
Derivative, fixed interest rate	3.87%
Derivative asset, fair value	$ 27,738		24,457
Derivative liability, fair value	0
Designated as Hedging Instrument | Unsecured term loan | Interest rate swaps
Derivative [Line Items]
Derivative asset, notional amount	$ 800,000
Derivative, fixed interest rate	4.04%
Derivative asset, fair value	$ 24,001		21,024
Derivative liability, fair value	0
Designated as Hedging Instrument | 100 West 33rd Street mortgage loan | Interest rate swaps
Derivative [Line Items]
Derivative asset, notional amount	$ 480,000
Derivative, fixed interest rate	5.06%
Derivative asset, fair value	$ 11,203		6,886
Derivative liability, fair value	0
Designated as Hedging Instrument | 888 Seventh Avenue mortgage loan | Interest rate swaps
Derivative [Line Items]
Derivative asset, notional amount	$ 200,000
Derivative, fixed interest rate	4.76%
Derivative asset, fair value	$ 7,880		6,544
Derivative liability, fair value	0
Long term debt	$ 67,000
Rate (as percent)	6.96%
Designated as Hedging Instrument | 888 Seventh Avenue mortgage loan | Interest rate swaps | SOFR
Derivative [Line Items]
Derivative, basis spread on variable rate (as percent)	1.80%
Designated as Hedging Instrument | 4 Union Square South mortgage loan | Interest rate swaps
Derivative [Line Items]
Derivative asset, notional amount	$ 99,100
Derivative, fixed interest rate	3.74%
Derivative asset, fair value	$ 3,916		4,050
Derivative liability, fair value	0
Long term debt	$ 20,900
Rate (as percent)	6.66%
Designated as Hedging Instrument | 4 Union Square South mortgage loan | Interest rate swaps | SOFR
Derivative [Line Items]
Derivative, basis spread on variable rate (as percent)	1.50%
Designated as Hedging Instrument | 1290 Avenue of the Americas mortgage loan | Interest Rate Cap
Derivative [Line Items]
Derivative asset, notional amount	$ 950,000
Derivative asset, fair value	66,456		7,590
Derivative liability, fair value	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 (as percent)	1.00%
Designated as Hedging Instrument | One Park Avenue mortgage loan | Interest Rate Cap
Derivative [Line Items]
Derivative asset, notional amount	$ 525,000
Derivative asset, fair value	10,870		$ 5,472
Derivative liability, fair value	$ 0
Designated as Hedging Instrument | One Park Avenue mortgage loan | Interest Rate Cap | SOFR
Derivative [Line Items]
Cap strike rate (as percent)	3.89%		3.89%
Designated as Hedging Instrument | One Park Avenue mortgage loan | Forward Cap | SOFR
Derivative [Line Items]
Cap strike rate (as percent)	3.89%
Designated as Hedging Instrument | Various mortgage loans | Interest Rate Cap
Derivative [Line Items]
Derivative asset, fair value	$ 3,110		$ 2,080
Derivative liability, fair value	0
Designated as Hedging Instrument | Unsecured Term Loan Expiring December 2027 | Interest rate swaps
Derivative [Line Items]
Derivative asset, notional amount		$ 800,000
Designated as Hedging Instrument | Unsecured Term Loan Expiring October 2023 | Interest rate swaps
Derivative [Line Items]
Derivative asset, notional amount	$ 800,000
Derivative, fixed interest rate	4.04%
Derivative liability, notional amount	$ 0
Designated as Hedging Instrument | Unsecured Term Loan Expiring July 2025 | Interest rate swaps
Derivative [Line Items]
Derivative asset, notional amount	$ 700,000
Derivative, fixed interest rate	4.52%
Derivative liability, notional amount	$ 100,000
Designated as Hedging Instrument | Unsecured Term Loan Expiring October 2026 | Interest rate swaps
Derivative [Line Items]
Derivative asset, notional amount	$ 550,000	$ 150,000
Derivative, fixed interest rate	4.35%
Derivative liability, notional amount	$ 250,000
Designated as Hedging Instrument | Unsecured Term Loan Expiring August 2027 | Interest rate swaps
Derivative [Line Items]
Derivative asset, notional amount	$ 50,000
Derivative, fixed interest rate	4.03%
Derivative liability, notional amount	$ 750,000
Designated as Hedging Instrument | 1290 Avenue of Americas mortgage loan Expiring November 2025 | Interest Rate Cap | SOFR
Derivative [Line Items]
Cap strike rate (as percent)	3.89%