Fair Value Measurements (Carrying Amounts And Estimated Fair Values Of Other Financial Instruments) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Current portion of note receivable, Carrying Amount	$ 0.6	$ 1.6
Current portion of note receivable, Fair Value	0.7	1.6
Long-term note receivable, Carrying Amount	0.1	0.8
Long-term note receivable, Fair Value	0.1	0.8
Short-term borrowings, Carrying Amount	2.6	90.0
Short-term borrowings, Fair Value	2.6	90.0
3.35% Senior notes, Carrying Amount	249.7	249.7
3.35% Senior notes, Fair Value	$ 260.2	$ 250.2
3.35% Senior Notes Due December 15, 2015 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate of debt	3.35%