cm:Concept: us-gaap:DilutiveSecurities
| Dilutive Securities, Effect on Basic Earnings Per Share |
| us-gaap:DilutiveSecurities |
| Amount of increase (decrease) to net income used for calculating diluted earnings per share (EPS), resulting from the assumed exercise stock options, restrictive stock units (RSUs), convertible preferred stock of an employee stock ownership plan (ESOP), and other dilutive convertible securities. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| For Period (duration) |
| Credit |
| false |
| us-gaap:DilutiveSecurities |