Deferred Consideration - Schedule of Deferred Consideration (Detail) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Contractual gold payments	$ 4,063	$ 3,110	$ 7,823	$ 6,208
Contractual gold payments – gold ounces paid	2,375	2,375	4,750	4,750
(Loss)/gain on revaluation of deferred consideration – gold payments	$ (23,358)	$ (4,037)	$ (25,566)	$ 367

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