v2.4.1.9

Goodwill and Other Intangible Assets - Changes In Goodwill (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012	Jul. 16, 2014	Dec. 01, 2014
Goodwill [Roll Forward]
Gross goodwill, beginning of period	$ 837,400us-gaap_GoodwillGross	[1]	$ 865,494us-gaap_GoodwillGross	[1]
Impact of foreign currency translation	(20,613)us-gaap_GoodwillTranslationAdjustments	[1]	(33,866)us-gaap_GoodwillTranslationAdjustments	[1]
Sale of subsidiary	(19,137)us-gaap_GoodwillWrittenOffRelatedToSaleOfBusinessUnit	[1]
Gross goodwill, end of period	1,133,873us-gaap_GoodwillGross	[1]	837,400us-gaap_GoodwillGross	[1]
Accumulated impairment, end of period	(17,508)us-gaap_GoodwillImpairedAccumulatedImpairmentLoss	[1]	(17,508)us-gaap_GoodwillImpairedAccumulatedImpairmentLoss	[1]
Net goodwill, end of period	1,116,365us-gaap_Goodwill	[1]	819,892us-gaap_Goodwill	[1]	847,986us-gaap_Goodwill
Evolution1
Goodwill [Roll Forward]
Acquisition	296,132us-gaap_GoodwillAcquiredDuringPeriod / us-gaap_BusinessAcquisitionAxis = wex_EvolutionOneMember	[1]
Net goodwill, end of period						296,132us-gaap_Goodwill / us-gaap_BusinessAcquisitionAxis = wex_EvolutionOneMember
ESSO Portfolio
Goodwill [Roll Forward]
Acquisition	40,091us-gaap_GoodwillAcquiredDuringPeriod / us-gaap_BusinessAcquisitionAxis = wex_ESSOPortfolioMember	[1]
Net goodwill, end of period							40,091us-gaap_Goodwill / us-gaap_BusinessAcquisitionAxis = wex_ESSOPortfolioMember
FastCred
Goodwill [Roll Forward]
Acquisition			5,772us-gaap_GoodwillAcquiredDuringPeriod / us-gaap_BusinessAcquisitionAxis = wex_FastCredMember	[1]
Net goodwill, end of period			4,282us-gaap_Goodwill / us-gaap_BusinessAcquisitionAxis = wex_FastCredMember
Fleet Payment Solutions Segment
Goodwill [Roll Forward]
Gross goodwill, beginning of period	754,886us-gaap_GoodwillGross / us-gaap_StatementBusinessSegmentsAxis = wex_FleetPaymentSolutionsMember	[1]	779,654us-gaap_GoodwillGross / us-gaap_StatementBusinessSegmentsAxis = wex_FleetPaymentSolutionsMember	[1]
Impact of foreign currency translation	(16,391)us-gaap_GoodwillTranslationAdjustments / us-gaap_StatementBusinessSegmentsAxis = wex_FleetPaymentSolutionsMember	[1]	(30,540)us-gaap_GoodwillTranslationAdjustments / us-gaap_StatementBusinessSegmentsAxis = wex_FleetPaymentSolutionsMember	[1]
Acquisition	0us-gaap_GoodwillAcquiredDuringPeriod / us-gaap_StatementBusinessSegmentsAxis = wex_FleetPaymentSolutionsMember	[1]
Sale of subsidiary	(19,137)us-gaap_GoodwillWrittenOffRelatedToSaleOfBusinessUnit / us-gaap_StatementBusinessSegmentsAxis = wex_FleetPaymentSolutionsMember	[1]
Gross goodwill, end of period	759,449us-gaap_GoodwillGross / us-gaap_StatementBusinessSegmentsAxis = wex_FleetPaymentSolutionsMember	[1]	754,886us-gaap_GoodwillGross / us-gaap_StatementBusinessSegmentsAxis = wex_FleetPaymentSolutionsMember	[1]
Accumulated impairment, end of period	(1,337)us-gaap_GoodwillImpairedAccumulatedImpairmentLoss / us-gaap_StatementBusinessSegmentsAxis = wex_FleetPaymentSolutionsMember	[1]	(1,337)us-gaap_GoodwillImpairedAccumulatedImpairmentLoss / us-gaap_StatementBusinessSegmentsAxis = wex_FleetPaymentSolutionsMember	[1]
Net goodwill, end of period	758,112us-gaap_Goodwill / us-gaap_StatementBusinessSegmentsAxis = wex_FleetPaymentSolutionsMember	[1]	753,549us-gaap_Goodwill / us-gaap_StatementBusinessSegmentsAxis = wex_FleetPaymentSolutionsMember	[1]
Fleet Payment Solutions Segment | ESSO Portfolio
Goodwill [Roll Forward]
Acquisition	40,091us-gaap_GoodwillAcquiredDuringPeriod / us-gaap_BusinessAcquisitionAxis = wex_ESSOPortfolioMember / us-gaap_StatementBusinessSegmentsAxis = wex_FleetPaymentSolutionsMember
Fleet Payment Solutions Segment | FastCred
Goodwill [Roll Forward]
Acquisition			5,772us-gaap_GoodwillAcquiredDuringPeriod / us-gaap_BusinessAcquisitionAxis = wex_FastCredMember / us-gaap_StatementBusinessSegmentsAxis = wex_FleetPaymentSolutionsMember	[1]
Other Payment Solutions Segment
Goodwill [Roll Forward]
Gross goodwill, beginning of period	82,514us-gaap_GoodwillGross / us-gaap_StatementBusinessSegmentsAxis = wex_OtherPaymentSolutionsMember	[1]	85,840us-gaap_GoodwillGross / us-gaap_StatementBusinessSegmentsAxis = wex_OtherPaymentSolutionsMember	[1]
Impact of foreign currency translation	(4,222)us-gaap_GoodwillTranslationAdjustments / us-gaap_StatementBusinessSegmentsAxis = wex_OtherPaymentSolutionsMember	[1]	(3,326)us-gaap_GoodwillTranslationAdjustments / us-gaap_StatementBusinessSegmentsAxis = wex_OtherPaymentSolutionsMember	[1]
Acquisition	296,132us-gaap_GoodwillAcquiredDuringPeriod / us-gaap_StatementBusinessSegmentsAxis = wex_OtherPaymentSolutionsMember	[1]
Sale of subsidiary	0us-gaap_GoodwillWrittenOffRelatedToSaleOfBusinessUnit / us-gaap_StatementBusinessSegmentsAxis = wex_OtherPaymentSolutionsMember	[1]
Gross goodwill, end of period	374,424us-gaap_GoodwillGross / us-gaap_StatementBusinessSegmentsAxis = wex_OtherPaymentSolutionsMember	[1]	82,514us-gaap_GoodwillGross / us-gaap_StatementBusinessSegmentsAxis = wex_OtherPaymentSolutionsMember	[1]
Accumulated impairment, end of period	(16,171)us-gaap_GoodwillImpairedAccumulatedImpairmentLoss / us-gaap_StatementBusinessSegmentsAxis = wex_OtherPaymentSolutionsMember	[1]	(16,171)us-gaap_GoodwillImpairedAccumulatedImpairmentLoss / us-gaap_StatementBusinessSegmentsAxis = wex_OtherPaymentSolutionsMember	[1]
Net goodwill, end of period	358,253us-gaap_Goodwill / us-gaap_StatementBusinessSegmentsAxis = wex_OtherPaymentSolutionsMember	[1]	66,343us-gaap_Goodwill / us-gaap_StatementBusinessSegmentsAxis = wex_OtherPaymentSolutionsMember	[1]
Other Payment Solutions Segment | ESSO Portfolio
Goodwill [Roll Forward]
Acquisition	0us-gaap_GoodwillAcquiredDuringPeriod / us-gaap_BusinessAcquisitionAxis = wex_ESSOPortfolioMember / us-gaap_StatementBusinessSegmentsAxis = wex_OtherPaymentSolutionsMember
Other Payment Solutions Segment | FastCred
Goodwill [Roll Forward]
Acquisition			$ 0us-gaap_GoodwillAcquiredDuringPeriod / us-gaap_BusinessAcquisitionAxis = wex_FastCredMember / us-gaap_StatementBusinessSegmentsAxis = wex_OtherPaymentSolutionsMember	[1]
[1] The prior year amounts have been adjusted to reflect changes as a result of finalizing the purchase accounting.

X

- Definition

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 20

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13816-109267



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Amount of increase in asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized resulting from a business combination.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 20

-Section 50

-Paragraph 1

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- Definition

Amount before accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 20

-Section 50

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Amount of accumulated impairment loss for an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 20

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- Definition

Amount of increase (decrease) from foreign currency translation adjustments of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

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Amount of divestiture of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 20

-Section 50

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