Business Combination - Summary of Allocation of Purchase Price (Detail) $ / shares in Units, $ in Thousands	Apr. 11, 2018 USD ($) $ / shares shares	Mar. 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
Cash and cash equivalents	13,687
Receivables and other current assets	14,069
Intangible assets	601,247
Other current liabilities	(17,314)
Fair value of net assets acquired	611,689
Goodwill	$ 84,057
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