Subsequent Events - Additional Information (Detail) - USD ($)		9 Months Ended
	Nov. 05, 2018	Sep. 30, 2018	Sep. 30, 2017	Oct. 09, 2018
Subsequent Event [Line Items]
Gross proceeds from issuance of common stock		$ 16,798,588	$ 40,063,542
Subsequent Event [Member]
Subsequent Event [Line Items]
Gross proceeds from issuance of common stock	$ 1,200,000
Subsequent Event [Member] | Portland Delayed Draw Commitment [Member]
Subsequent Event [Line Items]
Delayed draw commitment, amount				$ 2,500,000
Class A Common Stock [Member]
Subsequent Event [Line Items]
Sale of shares of common stock		51,000
Class A Common Stock [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Sale of shares of common stock	100,000
Class T Common Stock [Member]
Subsequent Event [Line Items]
Sale of shares of common stock		0
Class T Common Stock [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Sale of shares of common stock	5,000
Class W Common Stock [Member]
Subsequent Event [Line Items]
Sale of shares of common stock		27,000
Class W Common Stock [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Sale of shares of common stock	32,000