cm:Concept: us-gaap:TimeSharingTransactionsEffectOfChangesInEstimateInRelativeSalesValueMethod
| Time Sharing Transactions, Effect of Changes in Estimate in Relative Sales Value Method |
| us-gaap:TimeSharingTransactionsEffectOfChangesInEstimateInRelativeSalesValueMethod |
| Effects on income of the current period due to a material change in the estimate of revenue or cost under the relative sales method that affects several future periods. |
| cm:Concept |
| Text/String (xbrli:stringItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:TimeSharingTransactionsEffectOfChangesInEstimateInRelativeSalesValueMethod |