Summary of Significant Accounting Policies - Summary of Revenue from Contracts with Customers Disaggregated by Type of Revenue (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Disaggregation Of Revenue [Line Items]
Revenue from contracts with customers	$ 1,537	$ 2,506
Property Management Fee income
Disaggregation Of Revenue [Line Items]
Revenue from contracts with customers	766	863
Parking
Disaggregation Of Revenue [Line Items]
Revenue from contracts with customers	202	475
Leasing Commission income
Disaggregation Of Revenue [Line Items]
Revenue from contracts with customers	320	645
Other miscellaneous
Disaggregation Of Revenue [Line Items]
Revenue from contracts with customers	$ 248	$ 523