Variable Interest Entity - Summary of Information about Variable Interests (Parenthetical) (Detail) $ in Thousands	12 Months Ended
Dec. 31, 2019 USD ($)
Variable Interest Entity [Line Items]
Impairment of AdvisorEngine Financial Interests	$ 30,138

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.

No definition available.

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