cm:Concept: us-gaap:AdvancesReceivedOnGovernmentContractsNotNettedAgainstAccountsReceivable
| Advances Received on Government Contracts, Not Netted Against Accounts Receivable |
| us-gaap:AdvancesReceivedOnGovernmentContractsNotNettedAgainstAccountsReceivable |
| Advances received on government contracts that are not offset against receivables because they cannot be definitely regarded as payments on account for contract work in progress. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| As Of (instant) |
| Credit |
| false |
| us-gaap:AdvancesReceivedOnGovernmentContractsNotNettedAgainstAccountsReceivable |