Related Party Transactions - Summary of Revenues from Advisory Services Provided to Related Parties (Detail) - Advisory Services [Member] - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018
Related Party Transaction [Line Items]
Revenues from advisory services	$ 64,840	$ 58,456
WisdomTree Trust [Member]
Related Party Transaction [Line Items]
Revenues from advisory services	42,223	55,202
ETFS Issuers [Member]
Related Party Transaction [Line Items]
Revenues from advisory services	19,273
Boost Issuer PLC And WisdomTree Issuer plc [Member]
Related Party Transaction [Line Items]
Revenues from advisory services	2,504	2,626
WisdomTree Asset Management Canada, Inc [Member]
Related Party Transaction [Line Items]
Revenues from advisory services	546	311
WisdomTree Commodity Services LLC [Member]
Related Party Transaction [Line Items]
Revenues from advisory services	$ 294	$ 317

Amount of revenue, fees and commissions earned from transactions between (a) a parent company and its subsidiaries; (b) subsidiaries of a common parent; (c) an entity and trusts for the benefit of employees, for example, but not limited to, pension and profit-sharing trusts that are managed by or under the trusteeship of the entity's management; (d) an entity and its principal, owners, management, or members of their immediate families; and (e) affiliates.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 946
-SubTopic 220
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6-07.1(c))
-URI http://asc.fasb.org/extlink&oid=114873854&loc=SL114874292-224272

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.1(e))
-URI http://asc.fasb.org/extlink&oid=115205541&loc=SL114868664-224227

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