cm:Concept: us-gaap:SiteContingencyFactorsChangingEstimate
| Site Contingency, Factors Changing Estimate |
| us-gaap:SiteContingencyFactorsChangingEstimate |
| Factors that may cause a change in an estimate of a possible loss exposure that exceeds the amount accrued for the loss contingency, a recognized asset for third-party recoveries, an estimated loss contingency that has not been accrued, or a disclosed gain contingency for an individual site. |
| cm:Concept |
| Text/String (xbrli:stringItemType) |
| For Period (duration) |
| (no balance type) |
| false |
| us-gaap:SiteContingencyFactorsChangingEstimate |