Income from Continuing Operations Per Unrestricted Share (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Schedule of Basic and Diluted Earnings Per Share [Line Items]
Income from Continuing Operations	$ 38.0	$ 4.8	$ 78.9	$ 49.3
Dilutive Effect on Income of Equity-based Compensation Equivalent Shares	0.0	0.0	0.0	0.0
Diluted Income from Continuning Operations Attributed to Unrestricted Shares	$ 37.8	$ 4.8	$ 78.6	$ 49.1
Weighted-Average Unrestricted Shares Outstanding	51,611,800	52,605,300	51,737,600	54,245,700
Equity-based Compensation Equivalent Shares	60,200	94,600	78,200	110,500
Weighted-Average Unrestricted Shares and Equivalent Shares Outstanding Assuming Dilution	51,672,000	52,699,900	51,815,800	54,356,200
Basic Income from Continuing Operations Per Unrestricted Share (in dollars per share)	$ 0.73	$ 0.09	$ 1.52	$ 0.90
Diluted Income from Continuing Operations Per Untrestriced Share (in dollars per share)	$ 0.73	$ 0.09	$ 1.52	$ 0.90
Unrestricted Shares [Member]
Schedule of Basic and Diluted Earnings Per Share [Line Items]
Income from Continuing Operations	$ 37.8	$ 4.8	$ 78.6	$ 49.1
Participating Awards [Member]
Schedule of Basic and Diluted Earnings Per Share [Line Items]
Income from Continuing Operations	$ 0.2	$ 0.0	$ 0.3	$ 0.2