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Investments in Marketable Securities - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Investments, Debt and Equity Securities [Abstract]
Proceeds received from sales of marketable securities	$ 26.2	$ 15.1
Net realized gains on sale of marketable securities	(1.0)	$ 0.5
Variable Interest Entity, Primary Beneficiary
Investments in and Advances to Affiliates [Line Items]
Fair value of deconsolidated investment in affiliate	$ 33.2		$ 38.1

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- Definition

Marketable Securities, Fair Value, Deconsolidation

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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.

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- Definition

Amount of realized gain (loss) on investment in marketable security, including other-than-temporary impairment (OTTI).

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The cash inflow associated with the aggregate amount received by the entity through sale or maturity of marketable securities (held-to-maturity or available-for-sale) during the period.

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