v2.4.1.9

Accounts Receivable and Reserves for Credit Losses - Changes in Reserves for Credit Losses Related to Accounts Receivable (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance, beginning of period	$ 10,396us-gaap_AllowanceForDoubtfulAccountsReceivable	$ 11,709us-gaap_AllowanceForDoubtfulAccountsReceivable	$ 11,526us-gaap_AllowanceForDoubtfulAccountsReceivable
Provision for credit losses	32,144us-gaap_ProvisionForLoanLeaseAndOtherLosses	20,200us-gaap_ProvisionForLoanLeaseAndOtherLosses	22,539us-gaap_ProvisionForLoanLeaseAndOtherLosses
Charge-offs	(35,302)us-gaap_FinancingReceivableAllowanceForCreditLossesWriteOffs	(27,781)us-gaap_FinancingReceivableAllowanceForCreditLossesWriteOffs	(27,961)us-gaap_FinancingReceivableAllowanceForCreditLossesWriteOffs
Recoveries of amounts previously charged-off	6,832us-gaap_FinancingReceivableAllowanceForCreditLossesRecovery	6,663us-gaap_FinancingReceivableAllowanceForCreditLossesRecovery	5,605us-gaap_FinancingReceivableAllowanceForCreditLossesRecovery
Currency translation	(151)wex_FinancingReceivableAllowanceforCreditLossesTranslationAdjustments	(395)wex_FinancingReceivableAllowanceforCreditLossesTranslationAdjustments	0wex_FinancingReceivableAllowanceforCreditLossesTranslationAdjustments
Balance, end of period	$ 13,919us-gaap_AllowanceForDoubtfulAccountsReceivable	$ 10,396us-gaap_AllowanceForDoubtfulAccountsReceivable	$ 11,709us-gaap_AllowanceForDoubtfulAccountsReceivable

X

- Definition

For an unclassified balance sheet, a valuation allowance for receivables due a company that are expected to be uncollectible.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 4

-Article 5



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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 4

-URI http://asc.fasb.org/extlink&oid=35738203&loc=d3e5074-111524



Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.4)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_AllowanceForDoubtfulAccountsReceivable
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Definition

Amount of recovery of financing receivables doubtful of collection that were previously charged off.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 11B

-Subparagraph (c)(4)

-URI http://asc.fasb.org/extlink&oid=35738203&loc=SL6953423-111524

+ Details

Name:	us-gaap_FinancingReceivableAllowanceForCreditLossesRecovery
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

X

- Details

Name:	us-gaap_FinancingReceivableAllowanceForCreditLossesRollForward
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Amount of direct write-downs of financing receivables charged against the allowance.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 11B

-Subparagraph (c)(3)

-URI http://asc.fasb.org/extlink&oid=35738203&loc=SL6953423-111524

+ Details

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

X

- Definition

Amount of expense related loan transactions, lease transactions, credit loss from transactions other than loan and lease transactions, and other loss based on assessment of uncollectability from the counterparty to reduce the account to their net realizable value.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585



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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Paragraph 11

-Article 9



Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 225

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-04.11)

-URI http://asc.fasb.org/extlink&oid=6879574&loc=d3e536633-122882



Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 11B

-Subparagraph (c)(2)

-URI http://asc.fasb.org/extlink&oid=35738203&loc=SL6953423-111524

+ Details

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

X

- Definition

Financing Receivable Allowance for Credit Losses Translation Adjustments

+ References

No definition available.

+ Details

Name:	wex_FinancingReceivableAllowanceforCreditLossesTranslationAdjustments
Namespace Prefix:	wex_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration