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Goodwill and Intangible Assets - Summary of Indefinite-lived Intangible Assets (Detail) $ in Thousands	3 Months Ended
	Mar. 31, 2019 USD ($)
Indefinite-lived Intangible Assets [Line Items]
Beginning balance	$ 603,209
Foreign currency translation	42
Ending balance	603,251
Acquisition Of Etfs Business [Member]
Indefinite-lived Intangible Assets [Line Items]
Beginning balance	601,247
Ending balance	601,247
Questrade ETFs [Member]
Indefinite-lived Intangible Assets [Line Items]
Beginning balance	1,962
Foreign currency translation	42
Ending balance	$ 2,004

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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

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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

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- Definition

Amount of foreign currency translation gain (loss) which increases (decreases) an asset, excluding financial assets and goodwill, lacking physical substance and having a projected indefinite period of benefit to fair value.

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