Business Combination - Summary of Allocation of Purchase Price (Detail) $ / shares in Units, $ in Thousands	Apr. 11, 2018 USD ($) $ / shares shares	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Business Acquisition [Line Items]
WisdomTree stock price | $ / shares	$ 9.00
Goodwill		$ 85,856	$ 85,856
Acquisition of ETFS Business [Member]
Business Acquisition [Line Items]
Total shares issued | shares	30,000,000
WisdomTree stock price | $ / shares	$ 9.00
Equity portion of purchase price	$ 270,000
Term Loan (See Note 12)	200,000
Cash on hand	53,000
Purchase price	523,000
Deferred consideration (See Note 11)	172,746
Total	$ 695,746
Preferred Stock [Member] | Acquisition of ETFS Business [Member]
Business Acquisition [Line Items]
Total shares issued | shares	14,750
Conversion ratio	1,000
Common Stock [Member] | Acquisition of ETFS Business [Member]
Business Acquisition [Line Items]
Common stock equivalents | shares	14,750,000
Total shares issued | shares	15,250,000
Allocation of consideration [Member] | Acquisition of ETFS Business [Member]
Business Acquisition [Line Items]
Cash and cash equivalents	$ 13,687
Receivables and other current assets	14,069
Intangible assets(2)	601,247
Other current liabilities	(17,314)
Fair value of net assets acquired	611,689
Goodwill	$ 84,057