Document and Entity Information - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Mar. 19, 2019	Jun. 30, 2018
Document Information [Line Items]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2018
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	FY
Trading Symbol	ck0001698538
Entity Registrant Name	Strategic Student & Senior Housing Trust, Inc.
Entity Central Index Key	0001698538
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Non-accelerated Filer
Entity Emerging Growth Company	true
Entity Small Business	true
Entity Ex Transition Period	true
Entity Shell Company	false
Entity Public Float			$ 112
Class A Common Stock [Member]
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		11,100,000
Class T Common Stock [Member]
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		47,000
Class W Common Stock [Member]
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		67,000