Earnings Per Share (Reconciliation of Earnings to Earnings Attributable to Common Shares Used in Basic and Diluted Calculation) (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Earnings Per Share [Abstract]
Earnings from continuing operations	$ 64.2	$ 37.3	$ 153.0	$ 116.5
Earnings allocated to participating non-vested share awards	(0.2)	(0.1)	(0.5)	(0.4)
Earnings from continuing operations attributable to common shares	$ 64.0	$ 37.2	$ 152.5	$ 116.1

Amount after tax of income (loss) from continuing operations attributable to the parent.

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