cm:Level2TextBlock: us-gaap:AdvertisingCostsPolicyCapitalizedDirectResponseAdvertising
| Advertising Costs, Policy, Capitalized Direct Response Advertising [Policy Text Block] |
| us-gaap:AdvertisingCostsPolicyCapitalizedDirectResponseAdvertising |
| Disclosure of accounting policy for capitalizing direct response advertising costs, including a description of the qualifying activity and the types of costs capitalized, and the manner in which capitalized costs are recognized as expense and the basis for the timing thereof. The following amounts may also be disclosed: (1) total advertising costs reported as assets in each balance sheet presented and (2) any write-downs of capitalized advertising costs to net realizable value that are included in advertising expense. |
| cm:Level2TextBlock |
| Text Block (HTML) (nonnum:textBlockItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:AdvertisingCostsPolicyCapitalizedDirectResponseAdvertising |