| Document And Entity Information | Mar. 02, 2022 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Mar. 2, 2022 |
| Entity Registrant Name | Grayscale Bitcoin Cash Trust (BCH) |
| Entity Central Index Key | 0001732409 |
| Entity Emerging Growth Company | true |
| Entity File Number | 000-56308 |
| Entity Incorporation, State or Country Code | DE |
| Entity Tax Identification Number | 82-6867376 |
| Entity Address, Address Line One | c/o Grayscale Investments, LLC |
| Entity Address, Address Line Two | 290 Harbor Drive, 4th Floor |
| Entity Address, City or Town | Stamford |
| Entity Address, State or Province | CT |
| Entity Address, Postal Zip Code | 06902 |
| City Area Code | 212 |
| Local Phone Number | 668-1427 |
| Entity Information, Former Legal or Registered Name | N/A |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Entity Ex Transition Period | false |
| Title of 12(b) Security | N/A |
| Trading Symbol | BCHG |
| Security Exchange Name | NONE |
