Summary of Significant Accounting Policies - Summary of Revenue from Contracts with Customers Disaggregated by Type of Revenue (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Disaggregation Of Revenue [Line Items]
Revenue from Contracts with customers	$ 1,531	$ 2,419	$ 3,068	$ 4,925
Property Management Fee income
Disaggregation Of Revenue [Line Items]
Revenue from Contracts with customers	727	738	1,493	1,601
Parking
Disaggregation Of Revenue [Line Items]
Revenue from Contracts with customers	231	492	433	967
Leasing Commission income
Disaggregation Of Revenue [Line Items]
Revenue from Contracts with customers	344	522	664	1,168
Other miscellaneous
Disaggregation Of Revenue [Line Items]
Revenue from Contracts with customers	$ 229	$ 667	$ 477	$ 1,190