Related Party Transactions - Schedule of Amount Outstanding to Affiliates (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Related Party Transaction [Line Items]
Due to Affiliate	$ 1,008,000		$ 1,016,000
Operating Expense [Member]
Related Party Transaction [Line Items]
Percentage Of Operating Expenses Of Average Invested Assets	1.20%	1.30%
Percentage Of Operating Expenses Of Net Income	37.80%	33.30%
Asset And Property Management Fees [Member]
Related Party Transaction [Line Items]
Due to Affiliate	$ 812,000		768,000
Property Management Fee [Member]
Related Party Transaction [Line Items]
Due to Affiliate	138,000		145,000
Construction Management Fee [Member]
Related Party Transaction [Line Items]
Due to Affiliate	42,000		65,000
Operating Expense [Member]
Related Party Transaction [Line Items]
Due to Affiliate	15,000		12,000
Lease Commissions [Member]
Related Party Transaction [Line Items]
Due to Affiliate	1,000		21,000
Acquisition and development fees [Member]
Related Party Transaction [Line Items]
Due to Affiliate	$ 0		$ 5,000