Acquisitions - 2020 Acquisition (Details) - Mathway, LLC - USD ($) $ in Millions		12 Months Ended
Jun. 04, 2020	Dec. 31, 2020	Dec. 31, 2019
Business Acquisition [Line Items]
Fair value of purchase consideration	$ 101.0
Payments for contingent consideration arrangements	93.5
Escrow	$ 7.5
Escrow release period after acquisition	15 months
Contingent payments	$ 15.0
Contingent purchase consideration, cash		$ 2.9
Acquisition related expenses		3.1
Pro forma net income loss		$ 6.1	$ 27.3

Business Combination, Consideration Transferred, Escrow

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Business Combination, Consideration Transferred, Escrow Release Period After Acquisition

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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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The pro forma net Income or Loss for the period as if the business combination or combinations had been completed at the beginning of a period.

+ References

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-Name Accounting Standards Codification
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This element represents acquisition-related costs incurred to effect a business combination which costs have been expensed during the period. Such costs include finder's fees; advisory, legal, accounting, valuation, and other professional or consulting fees; general administrative costs, including the costs of maintaining an internal acquisitions department; and may include costs of registering and issuing debt and equity securities.

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Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer.

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- Definition

For contingent consideration arrangements recognized in connection with a business combination, this element represents an estimate of the high-end of the potential range (undiscounted) of the consideration which may be paid.

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Amount of liability recognized arising from contingent consideration in a business combination.

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The cash outflow associated with the acquisition of business during the period. The cash portion only of the acquisition price.

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