Earnings Per Share - Reconciliation of Net Income to Basic and Diluted EPS (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Earnings Per Share [Abstract]
Net income	$ 25.3	$ 28.4	$ 70.1	$ 78.7
Weighted average shares outstanding - Basic (shares)	60.3	60.2	60.3	60.1
Dilutive effect of common stock equivalents (shares)	1.0	1.2	1.2	1.2
Weighted average shares outstanding - Diluted (shares)	61.3	61.4	61.5	61.3
Basic earnings per share:
Earnings per share (usd per share)	$ 0.42	$ 0.47	$ 1.16	$ 1.31
Diluted earnings per share:
Earnings per share (usd per share)	$ 0.41	$ 0.46	$ 1.14	$ 1.28