cm:Concept: us-gaap:LongTermContractForPurchaseOfElectricPowerDescription
| Long-term Contract for Purchase of Electric Power, Description |
| us-gaap:LongTermContractForPurchaseOfElectricPowerDescription |
| Description of the arrangement to purchase electricity from a production plant constructed and financed by a public utility district, cooperative, or other organization with an expiration date longer than one year from the balance sheet date, including its form and substance. |
| cm:Concept |
| Text/String (xbrli:stringItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:LongTermContractForPurchaseOfElectricPowerDescription |