Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Numerator:
Net income	$ 143.1	$ 151.3	$ 211.2
Denominator:
Denominator for basic earnings per share — weighted average shares	35.4	35.0	35.7
Effect of dilutive securities:
Equity compensation plans	0.6	0.4	0.7
Denominator for diluted earnings per share — adjusted weighted average and assumed conversion	36.0	35.4	36.4
Basic earnings per share (in dollars per share)	$ 4.04	$ 4.33	$ 5.92
Diluted earnings per share (in dollars per share)	$ 3.98	$ 4.27	$ 5.81
Income from continuing operations	$ 143.1	$ 150.2	$ 180.8
Income (Loss) from Continuing Operations, Per Basic Share	$ 4.04	$ 4.30	$ 5.07
Discontinued Operation, Gain (Loss) on Disposal of Discontinued Operation, Net of Tax, Per Basic Share	$ 0	$ 0.03	$ 0.85
Total Discontinued Operations, Net of Taxes	$ 0.0	$ 1.1	$ 30.4
Income (Loss) from Continuing Operations, Per Diluted Share	$ 3.98	$ 4.24	$ 4.97
Discontinued Operation, Gain (Loss) on Disposal of Discontinued Operation, Net of Tax, Per Diluted Share	$ 0	$ 0.03	$ 0.84