Annual report pursuant to Section 13 and 15(d)

Income Taxes (Details 6)

v2.4.1.9
Income Taxes (Details 6) (USD $)
In Thousands, unless otherwise specified
12 Months Ended
Dec. 31, 2014
item
Dec. 31, 2013
item
Dec. 31, 2012
Reconciliation of unrecognized tax benefit      
Unrecognized tax benefits balance at beginning of year $ 2,058us-gaap_UnrecognizedTaxBenefits $ 1,097us-gaap_UnrecognizedTaxBenefits $ 364us-gaap_UnrecognizedTaxBenefits
Additions based on tax positions related to the current year 365us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions 181us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions 517us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromCurrentPeriodTaxPositions
Additions based on tax positions related to prior years 142us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions 1,045us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions 474us-gaap_UnrecognizedTaxBenefitsIncreasesResultingFromPriorPeriodTaxPositions
Reductions for settlements with taxing authorities related to prior years (261)us-gaap_UnrecognizedTaxBenefitsDecreasesResultingFromSettlementsWithTaxingAuthorities (56)us-gaap_UnrecognizedTaxBenefitsDecreasesResultingFromSettlementsWithTaxingAuthorities  
Reductions for lapses of statute of limitations (212)us-gaap_UnrecognizedTaxBenefitsReductionsResultingFromLapseOfApplicableStatuteOfLimitations (209)us-gaap_UnrecognizedTaxBenefitsReductionsResultingFromLapseOfApplicableStatuteOfLimitations (258)us-gaap_UnrecognizedTaxBenefitsReductionsResultingFromLapseOfApplicableStatuteOfLimitations
Unrecognized tax benefits balance at end of year 2,092us-gaap_UnrecognizedTaxBenefits 2,058us-gaap_UnrecognizedTaxBenefits 1,097us-gaap_UnrecognizedTaxBenefits
Unrecognized tax benefits that would impact effective tax rate, if recognized 1,973us-gaap_UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate    
Reasonably possible decrease in liability for unrecognized tax benefits in the next twelve months 1,469us-gaap_SignificantChangeInUnrecognizedTaxBenefitsIsReasonablyPossibleEstimatedRangeOfChangeUpperBound    
Number of states where the entity filed voluntary disclosure agreements   6env_NumberOfStatesWhereVoluntaryDisclosureAgreementsWereFiled  
Number of states where voluntary disclosure agreements were executed 3env_NumberOfStatesWhereVoluntaryDisclosureAgreementsWereFiledWithExecutedAgreements    
Number of states where voluntary disclosure agreements were closed 1env_NumberOfStatesWhereVoluntaryDisclosureAgreementsWereClosed    
Number of states where voluntary disclosure agreements were filed as required 3env_NumberOfStatesWhereVoluntaryDisclosureAgreementsFiledAsRequired    
Timeframe in which the voluntary disclosure agreements are expected to be settle 12 months    
Potential interest and penalties related to unrecognized tax benefits included in income tax expense/(benefit) (41)us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestExpense 33us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestExpense 448us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestExpense
Accrued interest and penalties on unrecognized tax benefits $ 594us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued $ 636us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestAccrued