| Cover | Dec. 30, 2021 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Dec. 30, 2021 |
| Entity File Number | 000-52566 |
| Entity Registrant Name | SUMMIT HEALTHCARE REIT, INC. |
| Entity Central Index Key | 0001310383 |
| Entity Tax Identification Number | 73-1721791 |
| Entity Incorporation, State or Country Code | MD |
| Entity Address, Address Line One | 2 South Pointe Drive |
| Entity Address, Address Line Two | Suite 100 |
| Entity Address, City or Town | Lake Forest |
| Entity Address, State or Province | CA |
| Entity Address, Postal Zip Code | 92630 |
| City Area Code | 800 |
| Local Phone Number | 978-8136 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | false |
