cm:Concept: us-gaap:PaymentsForProceedsFromShortTermInvestments
| Payments for (Proceeds from) Short-term Investments |
| us-gaap:PaymentsForProceedsFromShortTermInvestments |
| The net amount paid (received) by the reporting entity through acquisition or sale and maturities of short-term investments with an original maturity that is three months or less which qualify for treatment as an investing activity based on management's intention and intended by management to be liquidated, if necessary, within the current operating cycle. Includes cash flows from securities classified as trading securities that were acquired for reasons other than sale in the short-term. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| For Period (duration) |
| Credit |
| false |
| us-gaap:PaymentsForProceedsFromShortTermInvestments |