Fair Value Measurements - Schedule of Fair Value, Assets and Liabilities Measure on Recurring Basis (Details) - Fair Value, Recurring - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Financial assets:
Derivative financial instruments	$ 0.2
Total financial assets	20.2	$ 19.0
Financial liabilities:
Deferred compensation programs' liabilities	5.7	5.7
Total financial liabilities	5.7	5.7
Corporate bonds
Financial assets:
Trading debt securities:	4.0	5.0
Municipal bonds
Financial assets:
Trading debt securities:	0.3	0.3
Agency bonds
Financial assets:
Trading debt securities:	2.5
Floating rate notes
Financial assets:
Trading debt securities:	0.2	0.2
U.S. government securities
Financial assets:
Trading debt securities:	1.9	0.8
Asset-backed securities
Financial assets:
Trading debt securities:	4.3	5.4
Other
Financial assets:
Trading debt securities:	1.9	2.0
Preferred stocks
Financial assets:
Trading equity securities:	0.3	0.3
Equity Funds
Financial assets:
Trading equity securities:	0.6	0.6
Supplemental Employee Retirement Plan and Non-Qualified Deferred Compensation Plan | Mutual Fund
Financial assets:
Trading equity securities:	4.0	4.4
Level 1
Financial assets:
Derivative financial instruments	0.0
Total financial assets	12.3	12.6
Financial liabilities:
Deferred compensation programs' liabilities	0.0	0.0
Total financial liabilities	0.0	0.0
Level 1 | Corporate bonds
Financial assets:
Trading debt securities:	4.0	5.0
Level 1 | Municipal bonds
Financial assets:
Trading debt securities:	0.0	0.0
Level 1 | Agency bonds
Financial assets:
Trading debt securities:	0.0
Level 1 | Floating rate notes
Financial assets:
Trading debt securities:	0.2	0.2
Level 1 | U.S. government securities
Financial assets:
Trading debt securities:	1.9	0.8
Level 1 | Asset-backed securities
Financial assets:
Trading debt securities:	0.0	0.0
Level 1 | Other
Financial assets:
Trading debt securities:	1.3	1.3
Level 1 | Preferred stocks
Financial assets:
Trading equity securities:	0.3	0.3
Level 1 | Equity Funds
Financial assets:
Trading equity securities:	0.6	0.6
Level 1 | Supplemental Employee Retirement Plan and Non-Qualified Deferred Compensation Plan | Mutual Fund
Financial assets:
Trading equity securities:	4.0	4.4
Level 2
Financial assets:
Derivative financial instruments	0.2
Total financial assets	7.9	6.4
Financial liabilities:
Deferred compensation programs' liabilities	5.7	5.7
Total financial liabilities	5.7	5.7
Level 2 | Corporate bonds
Financial assets:
Trading debt securities:	0.0	0.0
Level 2 | Municipal bonds
Financial assets:
Trading debt securities:	0.3	0.3
Level 2 | Agency bonds
Financial assets:
Trading debt securities:	2.5
Level 2 | Floating rate notes
Financial assets:
Trading debt securities:	0.0	0.0
Level 2 | U.S. government securities
Financial assets:
Trading debt securities:	0.0	0.0
Level 2 | Asset-backed securities
Financial assets:
Trading debt securities:	4.3	5.4
Level 2 | Other
Financial assets:
Trading debt securities:	0.6	0.7
Level 2 | Preferred stocks
Financial assets:
Trading equity securities:	0.0	0.0
Level 2 | Equity Funds
Financial assets:
Trading equity securities:	0.0	0.0
Level 2 | Supplemental Employee Retirement Plan and Non-Qualified Deferred Compensation Plan | Mutual Fund
Financial assets:
Trading equity securities:	$ 0.0	$ 0.0