Consolidated Balance Sheets (Unaudited) (Parenthetical) (USD $)
In Millions, except Share data, unless otherwise specified
Jun. 30, 2012
Dec. 31, 2011
Current assets:    
Allowance for doubtful accounts $ 2.0 $ 2.4
Stockholders' equity:    
Common Stock, par or stated value per share (in dollars per share) $ 0.01 $ 0.01
Common Stock, shares authorized (in shares) 200,000,000 200,000,000
Common Stock, shares issued (in shares) 35,367,264 35,367,264
Treasury stock, shares (in shares) 2,257,860 2,344,060