v2.4.1.9

Commitments And Contingencies - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Office space, equipment, and vehicle
Commitments and Contingencies Disclosure [Line Items]
Lease expense	$ 8,838us-gaap_OperatingLeasesRentExpenseNet / us-gaap_PropertyPlantAndEquipmentByTypeAxis = us-gaap_PropertyPlantAndEquipmentMember	$ 7,257us-gaap_OperatingLeasesRentExpenseNet / us-gaap_PropertyPlantAndEquipmentByTypeAxis = us-gaap_PropertyPlantAndEquipmentMember	$ 5,601us-gaap_OperatingLeasesRentExpenseNet / us-gaap_PropertyPlantAndEquipmentByTypeAxis = us-gaap_PropertyPlantAndEquipmentMember
Technology and Software
Commitments and Contingencies Disclosure [Line Items]
Lease expense	9,852us-gaap_OperatingLeasesRentExpenseNet / us-gaap_PropertyPlantAndEquipmentByTypeAxis = wex_TechnologyAndSoftwareMember	8,249us-gaap_OperatingLeasesRentExpenseNet / us-gaap_PropertyPlantAndEquipmentByTypeAxis = wex_TechnologyAndSoftwareMember	6,959us-gaap_OperatingLeasesRentExpenseNet / us-gaap_PropertyPlantAndEquipmentByTypeAxis = wex_TechnologyAndSoftwareMember
Commitments to Extend Credit
Commitments and Contingencies Disclosure [Line Items]
Extension of credit to customers commitments, amount	$ 5,927,000us-gaap_LossContingencyEstimateOfPossibleLoss / us-gaap_LossContingenciesByNatureOfContingencyAxis = us-gaap_CommitmentsToExtendCreditMember	$ 5,650,000us-gaap_LossContingencyEstimateOfPossibleLoss / us-gaap_LossContingenciesByNatureOfContingencyAxis = us-gaap_CommitmentsToExtendCreditMember

X

- Definition

Reflects the estimated amount of loss from the specified contingency as of the balance sheet date.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 450

-SubTopic 20

-Section 50

-Paragraph 4

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=25496072&loc=d3e14435-108349



Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 450

-SubTopic 20

-Section 50

-Paragraph 9

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=25496072&loc=d3e14557-108349

+ Details

Name:	us-gaap_LossContingencyEstimateOfPossibleLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Rental expense for the reporting period incurred under operating leases, including minimum and any contingent rent expense, net of related sublease income.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 840

-SubTopic 20

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6453985&loc=d3e41499-112717

+ Details

Name:	us-gaap_OperatingLeasesRentExpenseNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

X

- Details

Name:	wex_CommitmentsAndContingenciesDisclosureLineItems
Namespace Prefix:	wex_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Details

Name:	us-gaap_LossContingenciesByNatureOfContingencyAxis=us-gaap_CommitmentsToExtendCreditMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_PropertyPlantAndEquipmentByTypeAxis=us-gaap_PropertyPlantAndEquipmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_PropertyPlantAndEquipmentByTypeAxis=wex_TechnologyAndSoftwareMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: