Commitments and Contingencies - Additional Information (Detail) a in Thousands, $ in Thousands, ft² in Millions		12 Months Ended
	Sep. 14, 2016 USD ($) a	Dec. 31, 2016 USD ($) ft² tenant	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Feb. 25, 2014 USD ($)
Commitments And Contingencies [Line Items]
Estimated remedian costs					$ 1,300
Deposits paid					1,400
Holdback escrow seller funded					1,300
Holdback escrow buyer funded					100
Maximum seller liability remediation costs					$ 1,300
Ground lease, expiration date		Jun. 01, 2062
Area of real estate property (square feet) | ft²		15.0
Commitments for tenant improvement and construction work		$ 10,100
Cash, FDIC Insured Amount		$ 250
Base Rent | Customer Concentration Risk
Commitments And Contingencies [Line Items]
Number of major tenants | tenant		0
Total Rental Revenues | Customer Concentration Risk
Commitments And Contingencies [Line Items]
Concentration risk, percentage		5.00%
Accounts Payable and Accrued Expenses
Commitments And Contingencies [Line Items]
Contingent liability		$ 1,100	$ 1,200
Other Assets
Commitments And Contingencies [Line Items]
Indemnification asset		1,100	1,200
Ground Rent
Commitments And Contingencies [Line Items]
Rent expense		100	100	$ 100
Ground Rent | Corona, CA [Member]
Commitments And Contingencies [Line Items]
Area of real estate property (square feet) | a	1,580
Lessee Leasing Arrangements, Operating Leases, Contingency Period	420 days
Lessee Leasing Arrangements, Operating Leases, Lease Commencement Period After Contingencies	30 days
Lessee Leasing Arrangements, Operating Leases, Lease Commencement Delay Period	24 months
Lessee Leasing Arrangements, Operating Leases, Term of Contract	99 years
Lessee Leasing Arrangements, Operating Leases, Period From Commencement To Rent Payments	9 months
Lessee Leasing Arrangements, Operating Leases, Period Of Base Rent Without Increase	10 years
Operating Leases, Rent Expense, Minimum Rentals	$ 956
Operating Leases, Rent Expense, Percent Increase In Rent	15.00%
Office Lease
Commitments And Contingencies [Line Items]
Rent expense		$ 500	$ 500	$ 400