Basis of Interim Financial Statements (Details Textual) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Basis of Interim Financial Statements (Textual) [Abstract]
Effect of Change in accounting estimate on income from continuing operation before income tax	$ 18.0	$ 20.7
Effect of Change in accounting estimate on income from continuing operation after income tax	$ 11.4	$ 13.1
Effect of Change in accounting estimate on Earnings Per Share	$ 0.09	$ 0.10