Amount of noncash expense for share-based payment arrangement.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3602-108585

+ Details

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

- Definition

Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=120381028&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 additional shares authorized for issuance under share-based payment arrangement.

+ References

No definition available.

+ Details

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

- Definition

Percentage of vesting of award under share-based payment arrangement.

+ References

+ Details

Name:	us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardAwardVestingRightsPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
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:	srt_StatementScenarioAxis=wetf_BelowTwentyFifthPercentileMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_StatementScenarioAxis=wetf_AtTwentyFifthPercentileMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_StatementScenarioAxis=wetf_AtFiftyPercentileMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_StatementScenarioAxis=wetf_At100thPercentileForGrantsMadeIn2019And2020Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_StatementScenarioAxis=wetf_At85thPercentileForGrantsMadeIn2021Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_AwardTypeAxis=wetf_PerformanceBasedRestrictedStockUnitMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Stock-Based Awards - Additional Information (Detail) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended
	Jun. 20, 2016	Mar. 31, 2021	Mar. 31, 2020
Share-based Payment Award
Stock option issuance period		10 years
Option vested period		1 year
Shares of common stock authorized to issue under equity award plan	10,000,000
Stock-based compensation expense		$ 3,143	$ 3,239
Below 25th Percentile [Member]
Share-based Payment Award
Shares granted and outstanding, Vesting percentage		0.00%
At 25th Percentile [Member]
Share-based Payment Award
Shares granted and outstanding, Vesting percentage		50.00%
At 50th Percentile [Member]
Share-based Payment Award
Shares granted and outstanding, Vesting percentage		100.00%
At 100th Percentile for grants made in 2019 and 2020 [Member]
Share-based Payment Award
Shares granted and outstanding, Vesting percentage		200.00%
At 85th Percentile for grants made in 2021 [Member]
Share-based Payment Award
Shares granted and outstanding, Vesting percentage		200.00%
Performance Based Restricted Stock Unit [Member] \| Maximum [Member]
Share-based Payment Award
Shares granted and outstanding, Vesting percentage		200.00%
Performance Based Restricted Stock Unit [Member] \| Minimum [Member]
Share-based Payment Award
Shares granted and outstanding, Vesting percentage		0.00%