Derivative Financial Instruments - Floating-to-Fixed Interest Rate Swaps (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Sep. 30, 2021	Dec. 31, 2020
Derivative [Line Items]
Notional Amount	$ 1,073,587		$ 874,606
Interest rate swaps
Derivative [Line Items]
Notional Amount	289,633
Not Designated as Hedging Instrument
Derivative [Line Items]
Notional Amount	449,579		200,000
Not Designated as Hedging Instrument | Interest rate swaps
Derivative [Line Items]
Notional Amount	50,000		50,000
Not Designated as Hedging Instrument | Senior Unsecured Term Loan 2.78% | Interest rate swaps
Derivative [Line Items]
Notional Amount	$ 50,000
Swap Fixed Rate	2.78%
Debt effective rate	4.33%
Designated as Hedging Instrument | Interest rate swaps
Derivative [Line Items]
Notional Amount	$ 239,633		$ 290,231
Designated as Hedging Instrument | Senior Unsecured Term Loan 3.02% | Interest rate swaps
Derivative [Line Items]
Notional Amount	$ 10,500
Swap Fixed Rate	3.02%
Debt effective rate	4.57%
Designated as Hedging Instrument | 249 Central Park Retail | Interest rate swaps
Derivative [Line Items]
Notional Amount	$ 33,372
Swap Fixed Rate	2.25%
Debt effective rate	3.85%
Designated as Hedging Instrument | Senior Unsecured Term Loan 2.26% | Interest rate swaps
Derivative [Line Items]
Notional Amount	$ 50,000
Swap Fixed Rate	2.26%
Debt effective rate	3.81%
Designated as Hedging Instrument | Senior Unsecured Term Loan 0.50% | Interest rate swaps
Derivative [Line Items]
Notional Amount	$ 25,000
Swap Fixed Rate	0.50%
Debt effective rate	2.05%
Designated as Hedging Instrument | Senior Unsecured Term Loan 0.50% | Interest rate swaps
Derivative [Line Items]
Notional Amount	$ 25,000
Swap Fixed Rate	0.50%
Debt effective rate	2.05%
Designated as Hedging Instrument | Senior Unsecured Term Loan 0.55% | Interest rate swaps
Derivative [Line Items]
Notional Amount	$ 25,000
Swap Fixed Rate	0.55%
Debt effective rate	2.10%
Designated as Hedging Instrument | Thames Street Wharf | Interest rate swaps
Derivative [Line Items]
Notional Amount		$ 70,761
Swap Fixed Rate		1.05%
Debt effective rate		2.35%