Annual report pursuant to Section 13 and 15(d)

Debt (Details)

v2.4.1.9
Debt (Details) (USD $)
In Thousands, unless otherwise specified
Dec. 31, 2014
Dec. 15, 2014
Outstanding debt obligations    
Unaccredited discount on Convertible Notes $ (4,612)us-gaap_DebtInstrumentUnamortizedDiscount  
Convertible Debt, Total 145,203us-gaap_ConvertibleDebt  
Unsecured debt | 1.75% convertible unsecured notes due December 2019    
Outstanding debt obligations    
Face amount and over-allotment amounts 172,500env_DebtInstrumentFaceAmountAndOverAllotments
/ us-gaap_DebtInstrumentAxis
= env_ConvertibleUnsecured1.75PercentNotesDueDecember2019Member
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_UnsecuredDebtMember
 
Unaccredited discount on Convertible Notes (27,297)us-gaap_DebtInstrumentUnamortizedDiscount
/ us-gaap_DebtInstrumentAxis
= env_ConvertibleUnsecured1.75PercentNotesDueDecember2019Member
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_UnsecuredDebtMember
(27,500)us-gaap_DebtInstrumentUnamortizedDiscount
/ us-gaap_DebtInstrumentAxis
= env_ConvertibleUnsecured1.75PercentNotesDueDecember2019Member
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_UnsecuredDebtMember
Convertible Debt, Total $ 145,203us-gaap_ConvertibleDebt
/ 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