Severance (Details) (USD $) In Millions, unless otherwise specified	Apr. 30, 2012	Jan. 31, 2012
Severance [Abstract]
Gross accrued severance liability	$ 50.7	$ 51.2
Amount deposited into insurance policies for funding severance liability	$ 35.2	$ 35.5

Amount deposited into insurance policies for funding severance liability.

No definition available.

Name:	cmvt_AmountDepositedIntoInsurancePoliciesForFundingSeveranceLiability
Namespace Prefix:	cmvt_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant