Related Party Transactions - Summary of Accounts Receivable from Related Parties (Detail) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Related Party Transaction [Line Items]
Accounts receivable from related parties	$ 27,258	$ 26,884
WisdomTree Trust [Member]
Related Party Transaction [Line Items]
Accounts receivable from related parties	14,347	13,030
Manjer Issuers [Member]
Related Party Transaction [Line Items]
Accounts receivable from related parties	11,134	11,693
WisdomTree Multi Asset Issuer PLC And WisdomTree Issuer PLC [Member]
Related Party Transaction [Line Items]
Accounts receivable from related parties	$ 1,777	2,125
WisdomTree Commodity Services LLC [Member]
Related Party Transaction [Line Items]
Accounts receivable from related parties		$ 36