Common Stock and Stock-Based Awards Plans - Stock-Based Compensation (Narrative) (Details) - USD ($) shares in Millions, $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Additional shares available for issuance	2.3		2.3
Compensation cost recognized for stock-based awards	$ 3.7	$ 4.8	$ 12.3	$ 13.3
Income tax benefit recognized in the income statement for stock-based awards	$ 0.8	$ 1.1	2.8	3.1
Total cash received as a result of stock option exercises			0.1	0.5
Tax benefit realized as a result of stock option exercises and the vesting of other share-based awards			2.6	2.5
Total intrinsic value of stock options exercised			$ 0.1	$ 0.4
Employee Stock Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Term of options			10 years
Employee Stock Option \| Employee Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period			4 years

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

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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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