Summary of Significant Accounting Policies - Revenue Recognition (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Disaggregation of Revenue [Line Items]
Type of Revenue	$ 2,427	$ 1,332	$ 4,378	$ 3,496
Parking income
Disaggregation of Revenue [Line Items]
Type of Revenue	1,880	1,227	3,538	3,278
Management fee income
Disaggregation of Revenue [Line Items]
Type of Revenue	419	69	658	147
Miscellaneous
Disaggregation of Revenue [Line Items]
Type of Revenue	$ 128	$ 36	$ 182	$ 71