| Document and Entity Information | Jun. 23, 2021 |
| Cover [Abstract] | |
| Amendment Flag | false |
| Entity Central Index Key | 0001632970 |
| Document Type | 8-K |
| Document Period End Date | Jun. 23, 2021 |
| Entity Registrant Name | Griffin-American Healthcare REIT IV, Inc. |
| Entity Incorporation State Country Code | MD |
| Entity File Number | 000-55775 |
| Entity Tax Identification Number | 47-2887436 |
| Entity Address, Address Line One | 18191 Von Karman Avenue |
| Entity Address, Address Line Two | Suite 300 |
| Entity Address, City or Town | Irvine |
| Entity Address, State or Province | CA |
| Entity Address, Postal Zip Code | 92612 |
| City Area Code | (949) |
| Local Phone Number | 270-9200 |
| Written Communications | true |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | true |
| Entity Ex Transition Period | true |
