Number of former owners of acquired entity that control entity that owns facility leased by entity.

No definition available.

Name:	cmn_NumberOfFormerOwnersOfAcquiredEntityControllingEntityOwningFacility
Namespace Prefix:	cmn_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of monthly base rent in current fiscal year under the terms of the lease agreement.

+ References

No definition available.

+ Details

Name:	cmn_OperatingLeasesMonthlyBaseRent
Namespace Prefix:	cmn_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of monthly base rent in year of lease expiration under escalation clause of lease agreement.

+ References

No definition available.

+ Details

Name:	cmn_OperatingLeasesMonthlyBaseRentInYearOfExpiration
Namespace Prefix:	cmn_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Represents the number of significant leases that contain escalation clauses.

+ References

No definition available.

+ Details

Name:	cmn_OperatingLeasesNumberOfSignificantLeasesThatContainEscalationClauses
Namespace Prefix:	cmn_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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

- Definition

Rental expense for the reporting period incurred under operating leases, including minimum and any contingent rent expense, net of related sublease income.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 840
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6453985&loc=d3e41499-112717

+ Details

Name:	us-gaap_OperatingLeasesRentExpenseNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=cmn_WaterPurificationAndFiltrationMember
Namespace Prefix:
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Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=cmn_HealthcareDisposablesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LeaseArrangementTypeAxis=cmn_LeaseArrangementUnitedStatesHeadquartersPhiladelphiaPennsylvaniaMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LeaseArrangementTypeAxis=cmn_LeaseArrangementCanadianHeadquartersTorontoOntarioMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LeaseArrangementTypeAxis=cmn_LeaseArrangementManufacturingAndWarehousingFacilitiesSharonPennsylvaniaMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LeaseArrangementTypeAxis=cmn_LeaseArrangementManufacturingAndWarehousingFacilitiesSantaFeSpringsCaliforniaMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LeaseArrangementTypeAxis=cmn_LeaseArrangementManufacturingAndWarehousingFacilitiesCubaNewYorkMember
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Data Type:	na
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- Details

Name:	us-gaap_LeaseArrangementTypeAxis=cmn_LeaseArrangementManufacturingAndWarehousingFacilitiesConroeParkTexasMember
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Commitments and Contingencies - Operating Leases (Details)	12 Months Ended
	Jul. 31, 2016 USD ($) item	Jul. 31, 2015 USD ($)	Jul. 31, 2014 USD ($)
Operating Leases
Number of significant leases that contain escalation clauses \| item	4
Rent expense	$ 6,675,000	$ 6,025,000	$ 4,409,000
Water Purification and Filtration
Operating Leases
Number of significant leases that contain escalation clauses \| item	2
Healthcare Disposables
Operating Leases
Number of significant leases that contain escalation clauses \| item	2
US Headquarters lease with escalation clauses , Philadelphia, Pennsylvania \| Water Purification and Filtration
Operating Leases
Monthly base rent	$ 17,200
Monthly base rent in year of lease expiration under escalation clause	20,100
Canadian Headquarters lease with escalation clauses, Toronto, Ontario \| Water Purification and Filtration
Operating Leases
Monthly base rent	12,800
Monthly base rent in year of lease expiration under escalation clause	13,300
Manufacturing and warehousing facilities lease with escalation clauses, Sharon, Pennsylvania \| Healthcare Disposables
Operating Leases
Monthly base rent	19,300
Monthly base rent in year of lease expiration under escalation clause	20,700
Manufacturing and warehousing facilities lease with escalation clauses, Santa Fe Springs, California \| Healthcare Disposables
Operating Leases
Monthly base rent	18,600
Monthly base rent in year of lease expiration under escalation clause	20,100
Manufacturing and warehousing facilities lease, Cuba, New York \| Healthcare Disposables
Operating Leases
Monthly base rent	$ 8,000
Number of former owners of Sterilator and current employees of the segment that control entity that owns facility \| item	2
Manufacturing and warehousing facilities lease, Conroe Park, Texas
Operating Leases
Monthly base rent	$ 31,800
Monthly base rent in year of lease expiration under escalation clause	$ 33,000