Income from Continuing Operations Per Unrestricted Share (Details) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Schedule of Basic and Diluted Earnings Per Share [Line Items]
Income from Continuing Operations	$ 9.3	$ 32.5	$ 44.5	$ 91.1
Dilutive Effect on Income of Equity-based Compensation Equivalent Shares	0	0	0	0
Diluted Income from Continuning Operations Attributed to Unrestricted Shares	9.3	32.3	44.3	90.6
Weighted-Average Unrestricted Shares Outstanding	54,666,500	57,519,000	54,989,700	57,824,700
Equity-based Compensation Equivalent Shares	106,600	110,400	118,400	110,400
Weighted-Average Unrestricted Shares and Equivalent Shares Outstanding Assuming Dilution	54,773,100	57,629,400	55,108,100	57,935,100
Basic Income from Continuing Operations Per Unrestricted Share (in dollars per share)	$ 0.17	$ 0.56	$ 0.80	$ 1.57
Diluted Income from Continuing Operations Per Untrestriced Share (in dollars per share)	$ 0.17	$ 0.56	$ 0.80	$ 1.57
Unrestricted Shares [Member]
Schedule of Basic and Diluted Earnings Per Share [Line Items]
Income from Continuing Operations	9.3	32.3	44.3	90.6
Participating Awards [Member]
Schedule of Basic and Diluted Earnings Per Share [Line Items]
Income from Continuing Operations	$ 0	$ 0.2	$ 0.2	$ 0.5