Note 3 - Revenue - Schedule of Changes in the Contract Assets (Details) $ in Thousands	3 Months Ended
Mar. 31, 2018 USD ($)
Contract With Customer Asset And Liability [Abstract]
Balance as of January 1, 2018	$ 51,896
Revenue recognized from performance obligations satisfied	72,031
Transferred to trade receivables	(34,751)
Currency impact	(186)
Balance as of March 31, 2018	$ 88,990

Amount of right to consideration in exchange for good or service transferred to customer when right is conditioned on something other than passage of time.

No definition available.

+ Details

Name:	cbm_ContractWithCustomerAsset
Namespace Prefix:	cbm_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Contract with customer asset, performance obligation satisfied, revenue recognized.

+ References

No definition available.

+ Details

Name:	cbm_ContractWithCustomerAssetPerformanceObligationSatisfiedRevenueRecognized
Namespace Prefix:	cbm_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- References

No definition available.

+ Details

Name:	us-gaap_ContractWithCustomerAssetAndLiabilityAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of increase (decrease) in revenue recognized for cumulative catch-up adjustment from change in estimate of transaction price which increases (decreases) right to consideration in exchange for good or service transferred to customer when right is conditioned on something other than passage of time. Includes, but is not limited to, change in assessment of whether estimate of variable consideration is constrained.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 10
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=82913847&loc=SL49130551-203045

+ Details

Name:	us-gaap_ContractWithCustomerAssetCumulativeCatchUpAdjustmentToRevenueChangeInEstimateOfTransactionPrice
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of decrease in right to consideration in exchange for good or service transferred to customer when right is conditioned on something other than passage of time from transfer to receivable due to right to consideration becoming unconditional.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 10
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=82913847&loc=SL49130551-203045

+ Details

Name:	us-gaap_ContractWithCustomerAssetReclassifiedToReceivable
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration