Intangible Assets and Liabilities - Intangible Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible liabilities, net	$ 56,521	$ 69,846
Below-Market Rents
Finite-Lived Intangible Assets [Line Items]
Accumulated amortization	(55,946)	(73,612)
Finite-lived intangible liabilities, net	54,929	68,219
Above-Market Ground Lease
Finite-Lived Intangible Assets [Line Items]
Accumulated amortization	(389)	(354)
Finite-lived intangible liabilities, net	$ 1,592	$ 1,627