Severance (Details) (USD $) In Millions	Jul. 31, 2011	Jan. 31, 2011
Severance
Gross accrued severance liability	$ 57.9	$ 61.9
Amount deposited into insurance policies for funding severance liability	$ 40.3	$ 44.7

Name:

cmvt_AmountDepositedIntoInsurancePoliciesForFundingSeveranceLiability

Namespace Prefix:

cmvt

Data Type:

xbrli:monetaryItemType

Balance Type:

debit

Period Type:

instant