cm:Level2TextBlock: us-gaap:RoyaltyTrustDistributableIncomePolicy
| Royalty Trust Distributable Income, Policy [Policy Text Block] |
| us-gaap:RoyaltyTrustDistributableIncomePolicy |
| Disclosure of accounting policy for a royalty trust in determining distributable income and how distributable income differs from income determined on the basis of US GAAP. |
| cm:Level2TextBlock |
| Text Block (HTML) (nonnum:textBlockItemType) |
| For Period (duration) |
| (no balance type) |
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| us-gaap:RoyaltyTrustDistributableIncomePolicy |