Income from Continuing Operations Per Unrestricted Share (Details) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Schedule of Basic and Diluted Earnings Per Share [Line Items]
Income from Continuing Operations	$ 35.2	$ 58.6
Dilutive Effect on Income of Equity-based Compensation Equivalent Shares	0	0
Diluted Income from Continuning Operations Attributed to Unrestricted Shares	35.0	58.3
Weighted-Average Unrestricted Shares Outstanding	55,312,900	58,130,500
Equity-based Compensation Equivalent Shares	130,200	110,300
Weighted-Average Unrestricted Shares and Equivalent Shares Outstanding Assuming Dilution	55,443,100	58,240,800
Basic Income from Continuing Operations Per Unrestricted Share (in dollars per share)	$ 0.63	$ 1.00
Diluted Income from Continuing Operations Per Untrestriced Share (in dollars per share)	$ 0.63	$ 1.00
Unrestricted Shares [Member]
Schedule of Basic and Diluted Earnings Per Share [Line Items]
Income from Continuing Operations	35.0	58.3
Participating Awards [Member]
Schedule of Basic and Diluted Earnings Per Share [Line Items]
Income from Continuing Operations	$ 0.2	$ 0.3