v2.4.1.9

Business Acquisitions and Other Intangible Assets Acquisitions - Additional Information - Acquisition of Fast Cred (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended					0 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012	Oct. 15, 2013
Business Acquisition [Line Items]
Consideration paid (net of cash acquired)	$ 891,725us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired		$ 11,277us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired		$ 402,475us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired
Goodwill	1,116,365us-gaap_Goodwill	[1]	819,892us-gaap_Goodwill	[1]	847,986us-gaap_Goodwill
FastCred
Business Acquisition [Line Items]
Consideration paid (net of cash acquired)						12,309us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired / us-gaap_BusinessAcquisitionAxis = wex_FastCredMember
Goodwill			4,282us-gaap_Goodwill / us-gaap_BusinessAcquisitionAxis = wex_FastCredMember
Allocated to other intangible assets			12,594us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibleAssetsOtherThanGoodwill / us-gaap_BusinessAcquisitionAxis = wex_FastCredMember
Increase in goodwill			1,490wex_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentGoodwill / us-gaap_BusinessAcquisitionAxis = wex_FastCredMember
Decrease in intangible assets			2,253us-gaap_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentIntangibles / us-gaap_BusinessAcquisitionAxis = wex_FastCredMember
Decrease in property, equipment and capitalized software			2us-gaap_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentPropertyPlantAndEquipment / us-gaap_BusinessAcquisitionAxis = wex_FastCredMember
Decrease in deferred income tax liabilities			$ 765wex_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentDeferredTaxLiabilities / us-gaap_BusinessAcquisitionAxis = wex_FastCredMember
FastCred | Customer relationships
Business Acquisition [Line Items]
Weighted average life						4 years
FastCred | Acquired software
Business Acquisition [Line Items]
Weighted average life						3 years
[1] The prior year amounts have been adjusted to reflect changes as a result of finalizing the purchase accounting.

X

- Definition

Weighted average amortization period of finite-lived intangible assets acquired either individually or as part of a group of assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 30

-Section 50

-Paragraph 1

-Subparagraph (a)(3)

-URI http://asc.fasb.org/extlink&oid=26713463&loc=d3e16265-109275

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

X

- Details

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

X

- Definition

This element represents the amount of any measurement period adjustment (as defined) realized during the reporting period to intangibles acquired in connection with a business combination for which the initial accounting was incomplete.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 10

-Section 50

-Paragraph 6

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=25497992&loc=d3e1500-128463

+ Details

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

X

- Definition

This element represents the amount of any measurement period adjustment (as defined) realized during the reporting period to property, plant, and equipment acquired in connection with a business combination for which the initial accounting was incomplete.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 10

-Section 50

-Paragraph 6

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=25497992&loc=d3e1500-128463

+ Details

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

X

- Definition

Amount of intangible assets, excluding goodwill, acquired at the acquisition date.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 805

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=39739317&loc=d3e4845-128472

+ Details

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

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



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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 20

-Section 45

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6388280&loc=d3e13770-109266

+ Details

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

X

- Definition

The cash outflow associated with the acquisition of a business, net of the cash acquired from the purchase.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Investing Activities

-URI http://asc.fasb.org/extlink&oid=6516133



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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 13

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3213-108585

+ Details

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Balance Type:	credit
Period Type:	duration

X

- Definition

Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Deferred Tax Liabilities

+ References

No definition available.

+ Details

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Balance Type:	credit
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X

- Definition

Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Goodwill

+ References

No definition available.

+ Details

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Namespace Prefix:	wex_
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Balance Type:	debit
Period Type:	duration

X

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: