Income From Continuing Operations Per Unrestricted Share (Details) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Schedule of Basic and Diluted Earnings Per Share [Line Items]
Income from Continuing Operations	$ 63.3	$ 4.8	$ 9.3	$ 35.2	$ 54.8	$ 68.6	$ 32.5	$ 58.6	$ 112.6	$ 214.5	$ 91.8
Dilutive Effect on Income of Equity-based Compensation Equivalent Shares									0	0	0
Diluted Income from Continuing Operations Attributed to Unrestricted Shares									112.1	213.4	91.3
Weighted-Average Unrestricted Shares Outstanding									53,762,500	56,856,900	58,857,300
Equity-based Compensation Equivalent Shares									105,400	126,700	141,700
Weighted-average Unrestricted Shares and Equivalent Shares Outstanding Assuming Dilution									53,867,900	56,983,600	58,999,000
Basic Income from Continuing Operations Per Unrestricted Share (per share)	$ 1.20	$ 0.09	$ 0.17	$ 0.63	$ 0.98	$ 1.21	$ 0.56	$ 1.00	$ 2.08	$ 3.75	$ 1.55
Diluted Income from Continuing Operations Per Unrestricted Share (per share)	$ 1.20	$ 0.09	$ 0.17	$ 0.63	$ 0.98	$ 1.21	$ 0.56	$ 1.00	$ 2.08	$ 3.74	$ 1.54
Common Stock [Member]
Schedule of Basic and Diluted Earnings Per Share [Line Items]
Income from Continuing Operations									112.1	213.4	91.3
Participating Awards [Member]
Schedule of Basic and Diluted Earnings Per Share [Line Items]
Income from Continuing Operations									$ 0.5	$ 1.1	$ 0.5