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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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Amount of cash inflow 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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Rate of weighted-average expected volatility for award under share-based payment arrangement.

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The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

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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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Percentage of vesting of award under share-based payment arrangement.

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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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Expected term of 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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Stock-Based Compensation Plans - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Long-Term Incentive Plan
Cash received from exercise of stock options	$ 0.2	$ 9.5	$ 11.6
Tax benefit from exercise of stock options		0.2	0.6
Intrinsic value of stock options exercised		$ 0.8	$ 2.8
Volatility (as a percent)	27.80%	29.90%	29.10%
Options granted (shares)	1,000,000
Expected term (in years)	7 years 2 months 23 days	7 years 3 months 10 days	7 years 10 days
Chief Executive Officer
Long-Term Incentive Plan
Expected term (in years)	7 years	7 years	7 years
Non-executive employees
Long-Term Incentive Plan
Options granted (shares)	0	0	0
Director
Long-Term Incentive Plan
Expected term (in years)	8 years	8 years	8 years
Employee Stock Option
Long-Term Incentive Plan
Unrecognized compensation cost	$ 2.8
Weighted average recognition period	2 years 4 months 24 days
Expected term (in years)	10 years
Employee Stock Option \| Employees
Long-Term Incentive Plan
Award expiration period	10 years
Award vesting period	4 years
Award vesting (as a percent)	25.00%
Restricted Stock Units \| Employees
Long-Term Incentive Plan
Award vesting period	3 years
Restricted Stock Units \| Employees \| Tranche One
Long-Term Incentive Plan
Award vesting period	3 years
Restricted Stock Units \| Employees \| Tranche Two
Long-Term Incentive Plan
Award vesting period	4 years
Financial PSUs
Long-Term Incentive Plan
Award vesting (as a percent)	100.00%
Financial PSUs \| Minimum
Long-Term Incentive Plan
Stock units granted that recipients receive as performance based restricted stock units (as a percent)	0.00%	0.00%
Financial PSUs \| Maximum
Long-Term Incentive Plan
Stock units granted that recipients receive as performance based restricted stock units (as a percent)	200.00%	200.00%
TSR PSUs
Long-Term Incentive Plan
Award vesting (as a percent)	100.00%
RSUs and PSUs
Long-Term Incentive Plan
Unrecognized compensation cost	$ 47.1
Weighted average recognition period	2 years 1 month 6 days
2015 LTIP
Long-Term Incentive Plan
Shares available for grant (shares)	10,500,000
2015 LTIP \| Non-employee Director
Long-Term Incentive Plan
Award vesting period	1 year
2015 LTIP \| Employee Stock Option \| Former CEO
Long-Term Incentive Plan
Long-term incentive award stock option awards (as a percent)	20.00%	20.00%
2015 LTIP \| Employee Stock Option \| Non-employee Director
Long-Term Incentive Plan
Award expiration period	10 years
2015 LTIP \| Restricted Stock Units \| Executives Officers excluding CEO
Long-Term Incentive Plan
Long-term incentive award restricted stock units (as a percent)	40.00%	40.00%
2015 LTIP \| Restricted Stock Units \| Former CEO
Long-Term Incentive Plan
Long-term incentive award restricted stock units (as a percent)	20.00%	20.00%
2015 LTIP \| Restricted Stock Units \| Senior Vice Presidents
Long-Term Incentive Plan
Long-term incentive award restricted stock units (as a percent)	50.00%	50.00%
2015 LTIP \| Financial PSUs \| Executives Officers excluding CEO
Long-Term Incentive Plan
Long-term incentive award performance based restricted stock units (as a percent)	60.00%	60.00%
2015 LTIP \| Financial PSUs \| Former CEO
Long-Term Incentive Plan
Long-term incentive award performance based restricted stock units (as a percent)	60.00%	60.00%
2015 LTIP \| Financial PSUs \| Senior Vice Presidents
Long-Term Incentive Plan
Long-term incentive award performance based restricted stock units (as a percent)	50.00%	50.00%