Stock-Based Awards - Additional Information (Detail) $ in Thousands	3 Months Ended
Mar. 31, 2016 USD ($) Equity_Plan shares	Mar. 31, 2015 USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock option issuance period	10 years
Option issued period	Options may be issued for terms of ten years
Number of equity award plans \| Equity_Plan	3
Issuance of common stock pursuant to stock options \| shares	23,000,000
Expire start date on options	Jun. 25, 2016
Expire end date on options	Nov. 15, 2021
Stock-based compensation expense \| $	$ 3,503	$ 2,344
Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Option vested period	2 years
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Option vested period	4 years

The aggregate amount of noncash, equity-based employee remuneration. This may include the value of stock or unit options, amortization of restricted stock or units, and adjustment for officers' compensation. As noncash, this element is an add back when calculating net cash generated by operating activities using the indirect method.

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=56944662&loc=d3e3602-108585

+ Details

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

- Definition

Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, 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 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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

- Definition

Number of share instruments newly issued under a share-based compensation plan.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuedInPeriod
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Description of pertinent provisions of equity-based compensation awards that have actual or potential impact upon the company's financial statements.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

+ Details

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

- Definition

Number of Equity Award Plans

+ References

No definition available.

+ Details

Name:	wetf_NumberOfEquityAwardPlans
Namespace Prefix:	wetf_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Share Based Compensation Arrangement By Share Based Payment Award Expiration Period End Date

+ References

No definition available.

+ Details

Name:	wetf_ShareBasedCompensationArrangementByShareBasedPaymentAwardExpirationPeriodEndDate
Namespace Prefix:	wetf_
Data Type:	xbrli:dateTimeItemType
Balance Type:	na
Period Type:	duration

- Definition

Share Based Compensation Arrangement By Share Based Payment Award Expiration Period Start Date

+ References

No definition available.

+ Details

Name:	wetf_ShareBasedCompensationArrangementByShareBasedPaymentAwardExpirationPeriodStartDate
Namespace Prefix:	wetf_
Data Type:	xbrli:dateTimeItemType
Balance Type:	na
Period Type:	duration

- Definition

Stock option issuance period.

+ References

No definition available.

+ Details

Name:	wetf_StockOptionIssuancePeriod
Namespace Prefix:	wetf_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: