v2.4.1.9
Derivative Instruments - Location and Amounts of Derivative Fair Values in Condensed Consolidated Balance Sheets (Details) (Commodity Contract, Fuel price derivatives, at fair value, Derivatives not designated as hedging instruments, USD $)
In Thousands, unless otherwise specified
Dec. 31, 2014
Dec. 31, 2013
Commodity Contract | Fuel price derivatives, at fair value | Derivatives not designated as hedging instruments
   
Derivatives, Fair Value [Line Items]    
Asset Derivatives $ 40,969us-gaap_DerivativeFairValueOfDerivativeAsset
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
/ wex_DerivativesFairValueNetByBalanceSheetLocationAxis
= wex_FuelPriceDerivativesAtFairValueMember
/ us-gaap_HedgingDesignationAxis
= us-gaap_NondesignatedMember
$ 0us-gaap_DerivativeFairValueOfDerivativeAsset
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
/ wex_DerivativesFairValueNetByBalanceSheetLocationAxis
= wex_FuelPriceDerivativesAtFairValueMember
/ us-gaap_HedgingDesignationAxis
= us-gaap_NondesignatedMember
Liability Derivatives $ 0us-gaap_DerivativeAssetFairValueGrossLiability
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
/ wex_DerivativesFairValueNetByBalanceSheetLocationAxis
= wex_FuelPriceDerivativesAtFairValueMember
/ us-gaap_HedgingDesignationAxis
= us-gaap_NondesignatedMember
$ 7,358us-gaap_DerivativeAssetFairValueGrossLiability
/ us-gaap_DerivativeInstrumentRiskAxis
= us-gaap_CommodityContractMember
/ wex_DerivativesFairValueNetByBalanceSheetLocationAxis
= wex_FuelPriceDerivativesAtFairValueMember
/ us-gaap_HedgingDesignationAxis
= us-gaap_NondesignatedMember