Note 9 - Other Income (Details Textual)	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016
Statement Line Items [Line Items]
Government grants, export incentive on gold	3.50%	2.50%

Export incentive on gold proceeds received from government grants.

No definition available.

Name:	cmcl_GovernmentGrantsExportIncentiveOnGold
Namespace Prefix:	cmcl_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration