Hedging Activities, Derivative Instruments and Fair Value Measurements - Fair Value Measurements (Details) - Recurring - USD ($) $ in Millions	Jun. 30, 2021	Dec. 31, 2020
Financial Assets
Foreign currency forwards	$ 0.4	$ 2.9
Trading securities held in deferred compensation plan	11.2	9.1
Total	11.6	12.0
Financial Liabilities
Foreign currency forwards	0.8	0.7
Deferred compensation plans	25.1	25.7
Total	25.9	26.4
Level 1
Financial Assets
Foreign currency forwards	0.0	0.0
Trading securities held in deferred compensation plan	11.2	9.1
Total	11.2	9.1
Financial Liabilities
Foreign currency forwards	0.0	0.0
Deferred compensation plans	25.1	25.7
Total	25.1	25.7
Level 2
Financial Assets
Foreign currency forwards	0.4	2.9
Trading securities held in deferred compensation plan	0.0	0.0
Total	0.4	2.9
Financial Liabilities
Foreign currency forwards	0.8	0.7
Deferred compensation plans	0.0	0.0
Total	0.8	0.7
Level 3
Financial Assets
Foreign currency forwards	0.0	0.0
Trading securities held in deferred compensation plan	0.0	0.0
Total	0.0	0.0
Financial Liabilities
Foreign currency forwards	0.0	0.0
Deferred compensation plans	0.0	0.0
Total	$ 0.0	$ 0.0