cm:Level1TextBlock: us-gaap:RestrictionsOnDividendsLoansAndAdvancesTextBlock
       
          
          | Restrictions on Dividends, Loans and Advances [Text Block] | 
       
       
          
          | us-gaap:RestrictionsOnDividendsLoansAndAdvancesTextBlock | 
       
       
          
          | The entire disclosure for a banking or savings institution's compliance during the year with (a) federal and state laws and regulations relative to dividend restrictions and (b) federal laws and regulations relative to insider loans. | 
       
       
          
          | cm:Level1TextBlock | 
       
       
          
          | Text Block (HTML) (nonnum:textBlockItemType) | 
       
       
          
          | For Period (duration) | 
       
       
          
          | (no balance type) | 
       
       
          
          | false | 
       
       
          
          | us-gaap:RestrictionsOnDividendsLoansAndAdvancesTextBlock | 
       
       
          
          | RestrictionsonDividendsLoansAndAdvances |