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Organization and Description of Business - Additional Information (Detail) - USD ($) $ in Thousands | 3 Months Ended
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Mar. 31, 2019 | Mar. 31, 2018
Organization Consolidation And Presentation Of Financial Statements [Line Items] |  |
Operating income | $ 10,683 | $ 13,221
WisdomTree Japan [Member] |  |
Organization Consolidation And Presentation Of Financial Statements [Line Items] |  |
Operating income | (430) | $ (1,232)
Impairment of Leasehold | $ 572 |
Acquisition of ETFS Business [Member] |  |
Organization Consolidation And Presentation Of Financial Statements [Line Items] |  |
Business Acquisition, Effective Date of Acquisition | Apr. 11, 2018 |

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- Definition The adjustment to reduce the value of existing agreements that specify the lessee's rights to use the leased property. This expense is charged when the estimates of future profits generated by the leased property are reduced. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 360 -SubTopic 10 -Section 45 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=109226348&loc=d3e2420-110228 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3602-108585 + Details
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