Severance (Details) (USD $) In Millions, unless otherwise specified	Oct. 31, 2011	Jan. 31, 2011
Severance [Abstract]
Gross accrued severance liability	$ 55.0	$ 61.9
Amount deposited into insurance policies for funding severance liability	$ 38.1	$ 44.7

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