Summary of Significant Accounting Policies - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2019 USD ($) Segment	Mar. 31, 2018 USD ($) Property	Dec. 31, 2018 USD ($)	Nov. 15, 2017
Summary of Significant Accounting Policies [Line Items]
Beneficial interest for ownership percentage	2.60%
Number of properties acquired | Property		3
Capitalized acquisition-related transaction costs		$ 1,700,000
Business acquisition, transaction costs	$ 0	200,000
Days allowed for lease cancellation	30 days
Estimated amortization expenses of intangible assets in 2019	$ 5,500,000
Estimated amortization expenses of intangible assets in 2020	3,800,000
Estimated amortization expenses of intangible assets in 2021	600,000
Debt issuance costs	$ 2,254,500		$ 2,184,030
Offering cost as percentage of gross offering proceeds	1.00%
Maximum period for reimbursement of offering cost	60 days
Maximum offering cost rate	3.50%
Maximum Dealer Manager sales commission as percentage of gross offering proceeds	6.00%
Maximum Dealer Manager fee as percentage of gross offering proceeds	3.00%			2.00%
Underwriting compensation	10.00%
Minimum percentage of ordinary taxable income to be distributed to stockholders	90.00%
Number of reportable segments | Segment	2
Class A Common Stock [Member]
Summary of Significant Accounting Policies [Line Items]
Maximum Dealer Manager sales commission as percentage of gross offering proceeds	6.00%
Maximum Dealer Manager fee as percentage of gross offering proceeds	3.00%
Class T Common Stock [Member]
Summary of Significant Accounting Policies [Line Items]
Maximum Dealer Manager sales commission as percentage of gross offering proceeds	3.00%
Maximum Dealer Manager fee as percentage of gross offering proceeds	3.00%
Daily stockholder servicing fee accrual description	1/365th of 1% of the purchase price per share
Class W Common Stock [Member]
Summary of Significant Accounting Policies [Line Items]
Maximum Dealer Manager fee as percentage of gross offering proceeds	9.00%
Daily stockholder servicing fee accrual description	1/365th of 0.5% of the purchase price per share
Maximum [Member]
Summary of Significant Accounting Policies [Line Items]
Initial term of lease	12 months
Maximum [Member] | Furniture, Fixtures and Equipment [Member]
Summary of Significant Accounting Policies [Line Items]
Standard depreciable life	7 years
Minimum [Member] | Furniture, Fixtures and Equipment [Member]
Summary of Significant Accounting Policies [Line Items]
Standard depreciable life	3 years
In-Place Leases [Member]
Summary of Significant Accounting Policies [Line Items]
Payments to acquire intangible assets	$ 0	$ 6,500,000
Gross amount of lease intangibles	22,300,000		22,300,000
Accumulated amortization of lease intangibles	$ 12,400,000		$ 10,600,000
Reno Student Housing, DST [Member]
Summary of Significant Accounting Policies [Line Items]
Beneficial interest for ownership percentage	2.60%
Power 5 Conference Student Housing [Member]
Summary of Significant Accounting Policies [Line Items]
Beneficial interest for ownership percentage	1.40%