Stock-Based Compensation - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total unrecognized compensation costs	$ 213.7
Recognized over a weighted-average period	1 year 9 months
Dividend yield	0.00%	0.00%	0.00%
Weighted-average grant-date fair value (per share)	$ 12.25	$ 29.86	$ 20.08
Total intrinsic value of options exercised	$ 30.6	$ 303.4	$ 84.0
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Dividend yield	0.00%
Restricted Stock Units (RSU)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Fair value of restricted stock vested	$ 32.4	$ 80.4	$ 22.3

Unrecognized cost of unvested share-based compensation awards.

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-Publisher FASB
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- Definition

Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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- Definition

Fair value of share-based awards for which the grantee gained the right by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash.

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- Definition

The estimated dividend rate (a percentage of the share price) to be paid (expected dividends) to holders of the underlying shares over the option's term.

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Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares.

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- Definition

The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

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