cm:Concept: us-gaap:PercentageOfUnamortizedFilmCostsDescription
| Percentage of Unamortized Film Costs, Description |
| us-gaap:PercentageOfUnamortizedFilmCostsDescription |
| Additional information about the amortization of films costs, including the period required to reach an amortization level of 80 percent, for unamortized film costs for released films, excluding acquired film libraries, that it expects to amortize within three years from the date of the balance sheet. |
| cm:Concept |
| Text/String (xbrli:stringItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:PercentageOfUnamortizedFilmCostsDescription |