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Goodwill and Intangible Assets - Summary of Indefinite-lived Intangible Assets (Detail) $ in Thousands | 9 Months Ended
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Sep. 30, 2018 USD ($)
Indefinite-lived Intangible Assets [Line Items] |
Beginning balance | $ 12,085
Foreign currency translation | (58)
Other increases/(decreases) | 601,247
Ending balance | 613,274
Acquisition of ETFS Business [Member] |
Indefinite-lived Intangible Assets [Line Items] |
Other increases/(decreases) | 601,247
Ending balance | 601,247
GreenHaven Commodity Services, LLC [Member] |
Indefinite-lived Intangible Assets [Line Items] |
Beginning balance | 9,953
Ending balance | 9,953
Questrade ETFs [Member] |
Indefinite-lived Intangible Assets [Line Items] |
Beginning balance | 2,132
Foreign currency translation | (58)
Ending balance | $ 2,074

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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
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- Definition Amount of assets, excluding financial assets and goodwill, lacking physical substance and having a projected indefinite period of benefit. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 30 -Section 50 -Paragraph 2 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16323-109275 + Details
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