Stock-Based and Deferred Compensation Plans - Summary of Stock Options and Stock Appreciation Rights Activity (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions	4 Months Ended	8 Months Ended	12 Months Ended
Dec. 31, 2021	Sep. 07, 2021	Dec. 31, 2020	Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Compensation expense for the year	$ 0.0	$ 4.3	$ 5.6	$ 7.4
Stock Options and Stock Appreciation Rights [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Shares, Outstanding and Exercisable, Beginning balance	0	143	144	151
Shares, Exercised	0	0	0	0
Shares, Forfeited	0	0	(1)	(7)
Shares, Awards cancelled pursuant to Merger Agreement	0	(143)	0	0
Shares, Outstanding and Exercisable, Ending balance	0	0	143	144
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Weighted-Average Exercise Price Per Share, Outstanding and Exercisable, Beginning balance	$ 0	$ 18.37	$ 18.35	$ 18.29
Weighted-Average Exercise Price Per Share, Exercised	0	0	0	0
Weighted-Average Exercise Price Per Share, Forfeited	0	0	17.05	17.05
Weighted Average Exercise Price Per Share, Awards cancelled pursuant to Merger Agreement	0	18.37	0	0
Weighted-Average Exercise Price Per Share, Outstanding and Exercisable, Ending balance	$ 0	$ 0	$ 18.37	$ 18.35
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Compensation expense for the year	$ 0.0	$ 0.0	$ 0.0	$ 0.0
Tax benefit related to compensation expense	0.0	0.0	0.0	0.0
Intrinsic value of awards exercised	0.0	0.0	0.0	0.0
Cash received from awards exercised	0.0	0.0	0.0	0.0
Grant date fair value of awards vested	$ 0.0	$ 0.0	$ 0.0	$ 0.0

Share based compensation arrangement by share based payment award options cancelled in period.

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- Definition

Share-based compensation arrangement by share-based payment award, options, outstanding and exercisable number.

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Share-based compensation arrangement by share-based payment award, options, outstanding and exercisable, weighted average exercise price.

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- Definition

The grant date fair value of stock options that have vested.

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Share based compensation arrangements by share based payment award options cancelled in period weighted average exercise price.

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- Definition

Amount of tax benefit for recognition of expense of award 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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Amount of noncash expense for 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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- Definition

The number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan.

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- Definition

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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Weighted average price at which option holders acquired shares when converting their stock options into shares.

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Weighted average price at which grantees could have acquired the underlying shares with respect to stock options that were terminated.

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

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