Summary of Significant Accounting Policies - Revenue Recognition (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Disaggregation of Revenue [Line Items]
Other operating	$ 1,966	$ 2,068	$ 3,928	$ 3,963
Parking Income
Disaggregation of Revenue [Line Items]
Other operating	1,870	1,819	3,603	3,445
Rental Lease Guaranty
Disaggregation of Revenue [Line Items]
Other operating	0	146	128	321
Management Fee Income
Disaggregation of Revenue [Line Items]
Other operating	64	69	133	137
Miscellaneous
Disaggregation of Revenue [Line Items]
Other operating	$ 32	$ 34	$ 64	$ 60