Income from Continuing Operations Per Unrestricted Share (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Schedule of Basic and Diluted Earnings Per Share [Line Items]
Income from Continuing Operations	$ 27.4	$ 9.3	$ 40.9	$ 44.5
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	$ 27.2	$ 9.3	$ 40.8	$ 44.3
Weighted-Average Unrestricted Shares Outstanding	51,728,100	54,666,500	51,800,500	54,989,700
Equity-based Compensation Equivalent Shares	78,000	106,600	87,200	118,400
Weighted-Average Unrestricted Shares and Equivalent Shares Outstanding Assuming Dilution	51,806,100	54,773,100	51,887,700	55,108,100
Basic Income from Continuing Operations Per Unrestricted Share (in dollars per share)	$ 0.53	$ 0.17	$ 0.79	$ 0.80
Diluted Income from Continuing Operations Per Untrestriced Share (in dollars per share)	$ 0.53	$ 0.17	$ 0.79	$ 0.80
Unrestricted Shares [Member]
Schedule of Basic and Diluted Earnings Per Share [Line Items]
Income from Continuing Operations	$ 27.2	$ 9.3	$ 40.8	$ 44.3
Participating Awards [Member]
Schedule of Basic and Diluted Earnings Per Share [Line Items]
Income from Continuing Operations	$ 0.2	$ 0.0	$ 0.1	$ 0.2