Quarterly report pursuant to Section 13 or 15(d)

Debt (Details 3)

v2.4.1.9
Debt (Details 3) (USD $)
In Thousands, except Per Share data, unless otherwise specified
0 Months Ended 3 Months Ended
Dec. 15, 2014
item
Mar. 31, 2015
Dec. 31, 2014
Dec. 15, 2014
Debt        
Discount   $ 4,418us-gaap_DebtInstrumentUnamortizedDiscount $ 4,612us-gaap_DebtInstrumentUnamortizedDiscount  
Accretion of debt discount   2,356us-gaap_AmortizationOfDebtDiscountPremium    
Unsecured debt | Convertible Notes        
Debt        
Face amount 172,500us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= env_ConvertibleUnsecured1.75PercentNotesDueDecember2019Member
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_UnsecuredDebtMember
    172,500us-gaap_DebtInstrumentFaceAmount
/ us-gaap_DebtInstrumentAxis
= env_ConvertibleUnsecured1.75PercentNotesDueDecember2019Member
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_UnsecuredDebtMember
Face amount and over-allotment amounts   172,500env_DebtInstrumentFaceAmountAndOverAllotments
/ us-gaap_DebtInstrumentAxis
= env_ConvertibleUnsecured1.75PercentNotesDueDecember2019Member
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_UnsecuredDebtMember
172,500env_DebtInstrumentFaceAmountAndOverAllotments
/ us-gaap_DebtInstrumentAxis
= env_ConvertibleUnsecured1.75PercentNotesDueDecember2019Member
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_UnsecuredDebtMember
 
Interest rate (as a percent) 1.75%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= env_ConvertibleUnsecured1.75PercentNotesDueDecember2019Member
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_UnsecuredDebtMember
1.75%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= env_ConvertibleUnsecured1.75PercentNotesDueDecember2019Member
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_UnsecuredDebtMember
1.75%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= env_ConvertibleUnsecured1.75PercentNotesDueDecember2019Member
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_UnsecuredDebtMember
1.75%us-gaap_DebtInstrumentInterestRateStatedPercentage
/ us-gaap_DebtInstrumentAxis
= env_ConvertibleUnsecured1.75PercentNotesDueDecember2019Member
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_UnsecuredDebtMember
Net proceeds from offering 166,967us-gaap_ProceedsFromDebtNetOfIssuanceCosts
/ us-gaap_DebtInstrumentAxis
= env_ConvertibleUnsecured1.75PercentNotesDueDecember2019Member
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_UnsecuredDebtMember
     
Repurchase percentage of principal (as a percent) 100.00%us-gaap_DebtInstrumentRedemptionPricePercentage
/ us-gaap_DebtInstrumentAxis
= env_ConvertibleUnsecured1.75PercentNotesDueDecember2019Member
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_UnsecuredDebtMember
     
Conversion rate 0.0159022us-gaap_DebtInstrumentConvertibleConversionRatio1
/ us-gaap_DebtInstrumentAxis
= env_ConvertibleUnsecured1.75PercentNotesDueDecember2019Member
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_UnsecuredDebtMember
     
Conversion price (in dollars per share) $ 62.88us-gaap_DebtInstrumentConvertibleConversionPrice1
/ us-gaap_DebtInstrumentAxis
= env_ConvertibleUnsecured1.75PercentNotesDueDecember2019Member
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_UnsecuredDebtMember
$ 62.88us-gaap_DebtInstrumentConvertibleConversionPrice1
/ us-gaap_DebtInstrumentAxis
= env_ConvertibleUnsecured1.75PercentNotesDueDecember2019Member
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_UnsecuredDebtMember
$ 62.88us-gaap_DebtInstrumentConvertibleConversionPrice1
/ us-gaap_DebtInstrumentAxis
= env_ConvertibleUnsecured1.75PercentNotesDueDecember2019Member
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_UnsecuredDebtMember
$ 62.88us-gaap_DebtInstrumentConvertibleConversionPrice1
/ us-gaap_DebtInstrumentAxis
= env_ConvertibleUnsecured1.75PercentNotesDueDecember2019Member
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_UnsecuredDebtMember
Threshold trading days (in days) 20us-gaap_DebtInstrumentConvertibleThresholdTradingDays
/ us-gaap_DebtInstrumentAxis
= env_ConvertibleUnsecured1.75PercentNotesDueDecember2019Member
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_UnsecuredDebtMember
     
Consecutive trading days 30 days      
Threshold percentage of stock price trigger (as a percent) 130.00%us-gaap_DebtInstrumentConvertibleThresholdPercentageOfStockPriceTrigger
/ us-gaap_DebtInstrumentAxis
= env_ConvertibleUnsecured1.75PercentNotesDueDecember2019Member
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_UnsecuredDebtMember
     
Threshold business days 5 days      
Threshold consecutive trading-day period 5 days      
Threshold percentage of trading price trigger (as a percent) 98.00%env_DebtInstrumentConvertibleThresholdPercentageOfTradingPriceTrigger
/ us-gaap_DebtInstrumentAxis
= env_ConvertibleUnsecured1.75PercentNotesDueDecember2019Member
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_UnsecuredDebtMember
     
Allocated to equity components 26,618us-gaap_DebtInstrumentConvertibleCarryingAmountOfTheEquityComponent
/ us-gaap_DebtInstrumentAxis
= env_ConvertibleUnsecured1.75PercentNotesDueDecember2019Member
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_UnsecuredDebtMember
    26,618us-gaap_DebtInstrumentConvertibleCarryingAmountOfTheEquityComponent
/ us-gaap_DebtInstrumentAxis
= env_ConvertibleUnsecured1.75PercentNotesDueDecember2019Member
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_UnsecuredDebtMember
Offering costs 882env_DebtInstrumentConvertibleCarryingAmountOfEquityComponentOfferingCosts
/ us-gaap_DebtInstrumentAxis
= env_ConvertibleUnsecured1.75PercentNotesDueDecember2019Member
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_UnsecuredDebtMember
    882env_DebtInstrumentConvertibleCarryingAmountOfEquityComponentOfferingCosts
/ us-gaap_DebtInstrumentAxis
= env_ConvertibleUnsecured1.75PercentNotesDueDecember2019Member
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_UnsecuredDebtMember
Discount 27,500us-gaap_DebtInstrumentUnamortizedDiscount
/ us-gaap_DebtInstrumentAxis
= env_ConvertibleUnsecured1.75PercentNotesDueDecember2019Member
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_UnsecuredDebtMember
26,089us-gaap_DebtInstrumentUnamortizedDiscount
/ us-gaap_DebtInstrumentAxis
= env_ConvertibleUnsecured1.75PercentNotesDueDecember2019Member
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_UnsecuredDebtMember
27,297us-gaap_DebtInstrumentUnamortizedDiscount
/ us-gaap_DebtInstrumentAxis
= env_ConvertibleUnsecured1.75PercentNotesDueDecember2019Member
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_UnsecuredDebtMember
27,500us-gaap_DebtInstrumentUnamortizedDiscount
/ us-gaap_DebtInstrumentAxis
= env_ConvertibleUnsecured1.75PercentNotesDueDecember2019Member
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_UnsecuredDebtMember
Accretion of debt discount   1,210us-gaap_AmortizationOfDebtDiscountPremium
/ us-gaap_DebtInstrumentAxis
= env_ConvertibleUnsecured1.75PercentNotesDueDecember2019Member
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_UnsecuredDebtMember
   
Effective interest rate on the liability component (as a percent)   6.10%us-gaap_DebtInstrumentInterestRateEffectivePercentage
/ us-gaap_DebtInstrumentAxis
= env_ConvertibleUnsecured1.75PercentNotesDueDecember2019Member
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_UnsecuredDebtMember
   
Unsecured debt | Convertible Notes | Other non-current assets        
Debt        
Issuance costs $ 4,651us-gaap_DeferredFinanceCostsNoncurrentGross
/ us-gaap_BalanceSheetLocationAxis
= us-gaap_OtherNoncurrentAssetsMember
/ us-gaap_DebtInstrumentAxis
= env_ConvertibleUnsecured1.75PercentNotesDueDecember2019Member
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_UnsecuredDebtMember
    $ 4,651us-gaap_DeferredFinanceCostsNoncurrentGross
/ us-gaap_BalanceSheetLocationAxis
= us-gaap_OtherNoncurrentAssetsMember
/ us-gaap_DebtInstrumentAxis
= env_ConvertibleUnsecured1.75PercentNotesDueDecember2019Member
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_UnsecuredDebtMember