CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) (USD $) In Millions, except Per Share data	Sep. 30, 2011	Dec. 31, 2010
Accounts receivable - trade, allowance for doubtful accounts	$ 8.1	$ 7.4
Property and equipment, accumulated depreciation	$ 214.4	$ 193.7
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	1.0	1.0
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	200.0	200.0
Common stock, shares issued	103.5	103.5