Organization - Additional Information (Detail)									1 Months Ended		3 Months Ended
	Apr. 17, 2020	Jul. 10, 2019 USD ($) $ / shares	May 01, 2018 USD ($) shares	Oct. 20, 2017	Sep. 28, 2017 USD ($) shares	Jan. 27, 2017 USD ($) shares	Oct. 05, 2016 USD ($) shares	Oct. 04, 2016 USD ($) shares	Jun. 30, 2019	Oct. 31, 2018	Mar. 31, 2021 USD ($) Property Employee $ / shares shares	Mar. 31, 2020 USD ($)
Organization and Nature of Operations [Line Items]
Date of formation of company											Oct. 04, 2016
Issuance of common stock												$ 3,313,673
Gross proceeds from issuance of common stock												$ 3,313,677
Number of senior housing properties | Property											4
Number of student housing properties | Property											2
Number of employees | Employee											0
Dealer manager agreement termination notice period	60 days
Strategic Storage Operating Partnership IV, L.P. [Member]
Organization and Nature of Operations [Line Items]
Date of formation of company											Oct. 05, 2016
Capital contribution							$ 1,000
Percentage of common units of limited partnership interest of operating partnership											99.80%
SSSHT Property Management, LLC (Property Manager) [Member]
Organization and Nature of Operations [Line Items]
Date of formation of company											Oct. 03, 2016
Reno Student Housing, DST [Member]
Organization and Nature of Operations [Line Items]
Beneficial interest for ownership percentage											2.60%
Beneficial interest percentage				2.60%
Power 5 Conference Student Housing [Member]
Organization and Nature of Operations [Line Items]
Number of student housing properties | Property											2
Beneficial interest for ownership percentage											1.40%
Beneficial interest percentage										1.40%	1.40%
Class Y Common Stock [Member]
Organization and Nature of Operations [Line Items]
Number of common stock issued | shares											1,100,000
Estimated value per share | $ / shares											$ 6.08
Class Z Common Stock [Member]
Organization and Nature of Operations [Line Items]
Number of common stock issued | shares											165,000
Estimated value per share | $ / shares											$ 6.08
Class A, T, W, Y and Z Common Stock [Member]
Organization and Nature of Operations [Line Items]
Gross proceeds from issuance of common stock											$ 17,100,000
Class A Common Stock [Member]
Organization and Nature of Operations [Line Items]
Number of common stock issued | shares											362,000
Estimated value per share | $ / shares											$ 6.08
Class T Common Stock [Member]
Organization and Nature of Operations [Line Items]
Number of common stock issued | shares											70,000
Estimated value per share | $ / shares											$ 6.08
Class W Common Stock [Member]
Organization and Nature of Operations [Line Items]
Number of common stock issued | shares											83,000
Estimated value per share | $ / shares											$ 6.08
Private Offering [Member]
Organization and Nature of Operations [Line Items]
Number of common stock issued | shares						10,800,000
Shares issued pursuant to distribution reinvestment plan | shares						1,000,000
Gross proceeds from issuance of common stock						$ 93,000,000
Primary Offering [Member] | Class Y Common Stock [Member]
Organization and Nature of Operations [Line Items]
Common stock sales price per share | $ / shares		$ 9.30
Primary Offering [Member] | Class Z Common Stock [Member]
Organization and Nature of Operations [Line Items]
Common stock sales price per share | $ / shares		9.30
Primary and Public Offering [Member] | Class A, T, W, Y and Z Common Stock [Member]
Organization and Nature of Operations [Line Items]
Shares issuable pursuant to distribution reinvestment plan per share | $ / shares		$ 9.30
SSSHT Advisor, LLC (Advisor) [Member] | Strategic Storage Operating Partnership IV, L.P. [Member]
Organization and Nature of Operations [Line Items]
Advisor purchased a limited partnership interest in operating partnership					$ 199,000		$ 1,000
Advisor acquired limited partnership interest in operating partnership, number of partnership units | shares					25,447.57		111.11
Capital contribution					$ 200,000
Percentage of common units of limited partnership interest of operating partnership											0.20%
SSSHT Advisor, LLC (Advisor) [Member] | Strategic Transfer Agent Services, LLC (Transfer Agent) [Member]
Organization and Nature of Operations [Line Items]
Ownership percentage											100.00%
SSSHT Advisor, LLC (Advisor) [Member] | Common Stock [Member]
Organization and Nature of Operations [Line Items]
Number of common stock issued | shares								111.11
Issuance of common stock								$ 1,000
SmartStop Asset Management, LLC (Sponsor) [Member] | SSSHT Advisor, LLC (Advisor) [Member]
Organization and Nature of Operations [Line Items]
Percentage of economic interest owned by sponsor									97.50%
Percentage of voting membership interests owned by sponsor									100.00%
SmartStop Asset Management, LLC (Sponsor) [Member] | SSSHT Property Management, LLC (Property Manager) [Member]
Organization and Nature of Operations [Line Items]
Percentage of property management owned by sponsor									100.00%
SmartStop Asset Management, LLC (Sponsor) [Member] | Select Capital Corporation (Dealer Manager) [Member]
Organization and Nature of Operations [Line Items]
Percentage of non-voting equity interest											15.00%
Affiliate [Member] | SSSHT Property Management, LLC (Property Manager) [Member]
Organization and Nature of Operations [Line Items]
Percentage owned by affiliate											2.50%
Maximum [Member] | Class Y Common Stock [Member]
Organization and Nature of Operations [Line Items]
Shares issuable pursuant to distribution reinvestment plan		$ 700,000,000
Maximum [Member] | Class Z Common Stock [Member]
Organization and Nature of Operations [Line Items]
Shares issuable pursuant to distribution reinvestment plan		$ 300,000,000
Maximum [Member] | Private Offering [Member]
Organization and Nature of Operations [Line Items]
Issuance of common stock						100,000,000
Maximum [Member] | Primary Offering [Member] | S-11 Registration Statement [Member]
Organization and Nature of Operations [Line Items]
Common stock shares registered for sale to public | shares			1,000,000,000.0
Maximum [Member] | Primary and Public Offering [Member] | S-11 Registration Statement [Member]
Organization and Nature of Operations [Line Items]
Shares issuable pursuant to distribution reinvestment plan			$ 95,000,000
Minimum [Member] | Private Offering [Member]
Organization and Nature of Operations [Line Items]
Issuance of common stock						$ 1,000,000