Common stock dividend rate percentage.

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- Definition

Share based compensation arrangement by share based payment awards, decrease in exercise due to stock dividend.

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- Definition

Share based compensation arrangement by share based payment awards, percentage increase in awards outstanding due to stock dividend.

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No definition available.

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- Definition

Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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Amount, after tax, of expense for award under share-based payment arrangement.

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- Definition

Aggregate carrying value as of the balance sheet date of the liabilities for stock option plans and other equity-based compensation arrangements payable within one year (or the operating cycle, if longer).

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- Definition

Aggregate cash paid by the entity during the period to settle equity instruments granted under equity-based payment arrangements.

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Amount of cost not yet recognized for nonvested award under share-based payment arrangement.

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Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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- Definition

Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.

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- Definition

Discount rate from fair value on offering date that participants pay for shares.

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- Definition

The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

+ References

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Weighted average remaining contractual term for equity-based awards excluding options, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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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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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

Number of additional shares authorized for issuance under share-based payment arrangement.

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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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Number of shares issued under share-based payment arrangement.

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- Definition

Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Number of share options (or share units) exercised during the current period.

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Share-based Compensation - Additional Information (Detail) - USD ($) $ in Millions	1 Months Ended	12 Months Ended
	May 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, award vesting period, years		5 years
Stock dividend declared, percent			15.00%
Percentage increase in number of awards outstanding due to stock dividend			15.00%
Reduction in exercise price of awards outstanding due to stock dividend			13.04%
Share-based payment expense		$ 16.9	$ 18.3	$ 12.3
Share-based payments expense, net of tax		15.5	$ 16.5	10.3
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employee service share-based compensation, unrecognized compensation costs on non-vested awards		$ 18.1
Employee service share-based compensation, unrecognized compensation costs weighted-average period, years		2 years
Share-based compensation arrangement by share-based payment award, total fair value of shares vested		$ 19.5
Options outstanding (in shares)		471,271	897,005
Restricted Stock Units (RSUs) [Member] \| Performance Condition [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options outstanding (in shares)		179,580
Stock-Settled SARs Activity [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Remaining contractual term		1 year 5 months 4 days
Exercised (in shares)		178,224
Share based compensation arrangement by share based payment award, shares issued (in shares)		69,498
Share based compensation arrangement by share based payment award options exercises, intrinsic value		$ 20.1
Cash-Settled SARs Activity [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercised (in shares)		52,298
Share based compensation arrangement by share based payment award options exercises, intrinsic value		$ 0.1
Employee service share-based compensation, cash paid to exercise of stock options		2.2
Liability for stock awards		0.1	$ 2.1
Share-based Payment Arrangement [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based payment expense		$ 0.5	$ 0.4	$ 0.4
2019 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of additional shares authorized (in shares)	1,885,000
Expiration period	10 years
Two Thousand Seven Employee Share Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, award vesting period, years		3 months
Discount from market price		85.00%
Earn Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Discount from market price		85.00%
Earn Plan [Member] \| Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, award vesting period, years		3 years
Earn Plan [Member] \| Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, award vesting period, years		5 years