Represents the number of separate incentive compensation programs within a incentive compensation plan.

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Period which an employee's right to exercise an award.

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Represents the number of share based compensation plans utilized by the entity.

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

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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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Amount of tax benefit from exercise of option under share-based payment arrangement.

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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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The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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

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

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The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

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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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Gross number of share options (or share units) granted during the period.

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Number of options outstanding, including both vested and non-vested options.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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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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Fair value of options vested. Excludes equity instruments other than options, for example, but not limited to, share units, stock appreciation rights, restricted stock.

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Purchase price of common stock expressed as a percentage of its fair value.

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SHARE-BASED AWARDS - SUMMARY (Details) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2021 USD ($) plan $ / shares shares	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Share-based expense (net of estimated forfeitures)
Total share-based expense \| $	$ 19.3	$ 18.8	$ 11.3
Intrinsic value of options exercised \| $		5.8	0.5
Tax benefit realized upon option exercise \| $	8.0	3.3	2.0
Fair value of stock vested \| $	33.5	$ 13.1	$ 8.2
Stock options
Share-based expense (net of estimated forfeitures)
Unrecognized compensation cost \| $	$ 0.0
Activity in the entity's stock option plans
Outstanding, end of period (in shares)	0
Exercisable, end of period (in shares)	0
Stock options, outstanding	0
Stock options, exercisable	0
Non-vested restricted stock units and performance-based equity awards
Share-based expense (net of estimated forfeitures)
Unrecognized compensation cost \| $	$ 20.8
Unrecognized compensation cost, weighted average period for recognition	1 year 8 months 12 days
Restricted Stock Units
Share-based compensation
Options granted, weighted average grant-date fair value (in dollars per share) \| $ / shares	$ 68.41
Activity in the entity's stock option plans
Added by performance factor (in shares)	172,000
2016 Plan
Share-based compensation
Common stock initially available for future issuance (in shares)	4,350,000
Additional shares authorized for issuance	0
Number of separate incentive compensation programs \| plan	4
Number of share based compensation plans within the entity's incentive compensation programs \| plan	3
2016 Plan \| Discretionary Grant Program
Share-based compensation
Minimum exercise price as a percentage of fair market value of common stock	100.00%
Exercisable period	3 years
Expiration Term	10 years
2016 Plan \| Time Based Restricted Stock Units \| Stock Issuance Program
Share-based compensation
Vesting period of awards granted	3 years
2016 Plan \| Time Based Restricted Stock Units \| Automatic Grant Program
Share-based compensation
Vesting period of awards granted	1 year
2016 Plan \| Performance Based Restricted Stock Units \| Stock Issuance Program
Share-based compensation
Vesting period of awards granted	3 years
2016 Plan \| Restricted Stock Units
Activity in the entity's stock option plans
Added by performance factor (in shares)	172,000