cm:Concept: us-gaap:InventoryAmountUnpricedChangeOrdersForLongTermContractsOrPrograms
| Inventory Amount, Unpriced Change Orders for Long-term Contracts or Programs |
| us-gaap:InventoryAmountUnpricedChangeOrdersForLongTermContractsOrPrograms |
| Amount of unpriced change orders or other similar items subject to uncertainty concerning their determination or ultimate realization included in inventory as of the balance sheet date. |
| cm:Concept |
| Monetary (xbrli:monetaryItemType) |
| As Of (instant) |
| Debit |
| false |
| us-gaap:InventoryAmountUnpricedChangeOrdersForLongTermContractsOrPrograms |