Deferred Consideration - Schedule of Deferred Consideration (Detail) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Contractual gold payments	$ 4,539	$ 3,502	$ 12,362	$ 9,710
Contractual gold payments – gold ounces paid	2,375	2,375	7,125	7,125
Loss on revaluation of deferred consideration – gold payments	$ (8,870)	$ (6,306)	$ (34,436)	$ (5,939)

Gain/loss from revaluation of deferred consideration.

No definition available.

Name:	wetf_GainLossFromChangeInDeferredConsideration
Namespace Prefix:	wetf_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration