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