Commitments and Contingencies - Narrative (Details) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2021 USD ($) ground_lease	Sep. 30, 2020 USD ($)
Long-term Purchase Commitment [Line Items]
Commitments for contracts and executed leases directly related to operating and development properties	$ 980.1		$ 980.1
Weighted average discount rate, ground leases	4.65%		4.65%
Weighted average remaining lease term	65 years		65 years
Variable lease, cost	$ 0.8	$ 0.7	$ 1.7	$ 2.4
Environmental matters [Member]
Long-term Purchase Commitment [Line Items]
Accrued environmental remediation liabilities	$ 77.2		$ 77.2
Ten year ground lease extension option [Member]
Long-term Purchase Commitment [Line Items]
Number of extension options | ground_lease			3
Ground lease extension option term			10 years
Forty-five year ground lease extension option [Member]
Long-term Purchase Commitment [Line Items]
Number of extension options | ground_lease			1
Ground lease extension option term			45 years