Related Party Transactions - Additional Information (Detail) - USD ($)				1 Months Ended	9 Months Ended
	May 01, 2018	Apr. 30, 2018	Oct. 20, 2017	Oct. 31, 2018	Sep. 30, 2018	Sep. 06, 2018	Nov. 15, 2017
Related Party Transaction [Line Items]
Maximum period for reimbursement of offering cost					60 days
Maximum offering cost rate					3.50%
Reimbursement of offering cost rate					1.00%
Acquisition fee as percentage of contract purchase price					2.00%
Monthly asset management fee					0.05417%
Monthly asset management fee one twelfth of less than one percentage of average invested assets					one twelfth of 0.65%
Underwriting compensation					10.00%
Maximum Dealer Manager fee as percentage of gross offering proceeds					3.00%		2.00%
Reno Student Housing, DST [Member]
Related Party Transaction [Line Items]
Proceeds from Private Offering			$ 1,030,000
Beneficial interest percentage			2.60%
Power 5 Conference Student Housing [Member]
Related Party Transaction [Line Items]
Beneficial interest percentage				1.40%
Proceeds from issuance of preferred units in operating partnership				$ 800,000
Class A Common Stock [Member]
Related Party Transaction [Line Items]
Maximum Dealer Manager fee as percentage of gross offering proceeds					3.00%
Class T Common Stock [Member]
Related Party Transaction [Line Items]
Maximum Dealer Manager fee as percentage of gross offering proceeds					3.00%
Class W Common Stock [Member]
Related Party Transaction [Line Items]
Maximum Dealer Manager fee as percentage of gross offering proceeds					9.00%
Maximum [Member]
Related Party Transaction [Line Items]
Financing fee percentage		0.50%
Advisory Agreements [Member]
Related Party Transaction [Line Items]
Maximum period for reimbursement of offering cost					60 days
Maximum offering cost rate					3.50%
Reimbursement of offering cost rate					1.00%
Gross proceeds from offering, threshold percentage of expenses for reimbursement					15.00%
Acquisition fee as percentage of contract purchase price						1.75%
Monthly asset management fee	0.05208%
Monthly asset management fee one twelfth of less than one percentage of average invested assets					one twelfth of 0.625%
Increase in monthly asset management fee	0.66667%
Increase in monthly asset management fee one twelfth of less than one percentage of average invested assets					one twelfth of 0.8%
Disposition fees percentage of sale price of property					3.00%
Operating expenses reimbursement percentage of average investment in assets					2.00%
Operating expenses reimbursement percentage of net income					25.00%
Operating expenses exceed limitation					12 months
Maximum days for disclosure fact					60 days
Dealer Manager [Member]
Related Party Transaction [Line Items]
Maximum dealer manager commission fee percentage of proceeds from Primary Offering					3.00%
Maximum dealer manager fee percentage of proceeds from sales in Primary Private Offering					2.00%
Underwriting compensation					10.00%
Maximum Dealer Manager fee as percentage of gross offering proceeds					3.00%
Percentage of non-voting equity interest					15.00%
Percentage owned by affiliate in advisor					2.50%
Dealer Manager [Member] | Primary Offering Dealer Manager Agreement [Member]
Related Party Transaction [Line Items]
Underwriting compensation					10.00%
Dealer Manager [Member] | Class A Common Stock [Member]
Related Party Transaction [Line Items]
Sale commission fees percentage of proceed from Primary Offering					6.00%
Maximum dealer manager fee percentage of proceeds from sales in Primary Private Offering					3.00%
Dealer Manager [Member] | Class T Common Stock [Member]
Related Party Transaction [Line Items]
Sale commission fees percentage of proceed from Primary Offering					3.00%
Maximum dealer manager fee percentage of proceeds from sales in Primary Private Offering					3.00%
Dealer Manager [Member] | Class T Common Stock [Member] | Additional Paid In Capital Selling Commissions [Member]
Related Party Transaction [Line Items]
Monthly stockholder servicing fee accrual description					accrues daily in an amount equal to 1/365th of 0.5% of the purchase price per share
Dealer Manager [Member] | Class W Common Stock [Member]
Related Party Transaction [Line Items]
Servicing fee percentage					9.00%
Dealer Manager [Member] | Class W Common Stock [Member] | Additional Paid In Capital Selling Commissions [Member]
Related Party Transaction [Line Items]
Monthly stockholder servicing fee accrual description					accrues daily in an amount equal to 1/365th of 0.5% of the purchase price per share
Dealer Manager [Member] | Maximum [Member]
Related Party Transaction [Line Items]
Sale commission fees percentage of proceed from Primary Offering					6.00%
SmartStop Asset Management [Member]
Related Party Transaction [Line Items]
Transfer Agent, one-time initial setup fee					$ 50,000
Property Managers [Member]
Related Party Transaction [Line Items]
Property Managers fee percentage description					Effective May 1, 2018, we now pay our Property Manager an oversight fee equal to 1% of the gross revenues attributable to such properties; provided, however, that our Property Manager will receive an oversight fee equal to 1.5% of the gross revenues attributable to any senior housing property other than such properties that are leased to third party tenants under triple-net or similar lease structures. In the event any of our properties are managed directly by our Property Manager, we will pay our Property Manager a property management fee that is approved by a majority of our board of directors, including a majority of our independent directors not otherwise interested in such transaction, as being fair and reasonable to us and on terms and conditions not less favorable to us than those available from unaffiliated third parties.
Percentage of oversight fee equal to gross revenues					1.00%
Property Managers [Member] | Senior Housing Properties [Member]
Related Party Transaction [Line Items]
Percentage of oversight fee equal to gross revenues					1.50%