Shareholders' Equity - Changes in Shareholders' Equity (Details) - USD ($) shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Other comprehensive income (loss)	$ (21.6)	$ 6.8
Common Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance (in shares)	20.6	20.7
Beginning balance	$ 0.2	$ 0.2
Shares repurchases (in shares)	(0.1)	0.0
Incentive plan activity (in shares)	0.0	0.1
Balance (in shares)	20.5	20.8
Ending balance	$ 0.2	$ 0.2
Additional Paid-in Capital
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	292.1	301.0
Share repurchases	(5.3)	(2.4)
Incentive plan activity	1.0	1.2
Other	(1.5)
Ending balance	286.3	299.8
Retained Earnings
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	632.2	603.3
Adoption of new accounting standard	(0.1)	11.5
Net income	218.7	13.1
Dividends ($0.26 per share)	(5.3)	(5.3)
Ending balance	845.5	622.6
Accumulated Other Comprehensive Loss
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(36.4)	(45.5)
Adoption of new accounting standard		(11.5)
Other comprehensive income (loss)	(22.5)	6.8
Ending balance	(58.9)	(50.2)
Treasury Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	(1.2)	(1.3)
Ending balance	(1.2)	(1.3)
Total Permanent Shareholders' Equity
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	886.9	857.7
Adoption of new accounting standard	(0.1)
Net income	218.7	13.1
Other comprehensive income (loss)	(22.5)	6.8
Dividends ($0.26 per share)	(5.3)	(5.3)
Share repurchases	(5.3)	(2.4)
Incentive plan activity	1.0	1.2
Other	(1.5)
Ending balance	1,071.9	$ 871.1
Redeemable non-controlling interest
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	28.0
Net income	0.1
Other comprehensive income (loss)	0.9
Ending balance	$ 29.0