Summary of Significant Accounting Policies - Summary of Revenue from Contracts with Customers Disaggregated by Type of Revenue (Detail) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017
Disaggregation Of Revenue [Line Items]
Revenue from Contracts with customers	$ 3,970	$ 9,548
Property Management Fee income
Disaggregation Of Revenue [Line Items]
Revenue from Contracts with customers	1,762	3,108
Parking
Disaggregation Of Revenue [Line Items]
Revenue from Contracts with customers	514	1,780
Leasing Commission income
Disaggregation Of Revenue [Line Items]
Revenue from Contracts with customers	742	2,134
Other miscellaneous
Disaggregation Of Revenue [Line Items]
Revenue from Contracts with customers	$ 952	$ 2,526

Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=109196051&loc=SL49130543-203045

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=109196051&loc=SL49130539-203045

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=109196051&loc=SL49130545-203045

Name:	us-gaap_RevenueFromContractWithCustomerExcludingAssessedTax
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration