cm:Concept: us-gaap:StatutoryAccountingPracticesRetainedEarningsNotAvailableForDividends
| Statutory Accounting Practices, Retained Earnings Not Available for Dividends |
| us-gaap:StatutoryAccountingPracticesRetainedEarningsNotAvailableForDividends |
| The amount of retained earnings as of the balance sheet date that cannot be distributed to stockholders pursuant to statutory rules and regulations. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| As Of (instant) |
| Credit |
| false |
| us-gaap:StatutoryAccountingPracticesRetainedEarningsNotAvailableForDividends |