CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) 10Q (USD $)
In Millions, except Share data, unless otherwise specified
Mar. 31, 2015
Dec. 31, 2014
Statement Of Financial Position [Abstract]    
Property and equipment, accumulated depreciation $ 323.1 $ 312.0
Preferred stock, par value $ 0.01 $ 0.01
Preferred stock, shares authorized 1,000,000 1,000,000
Preferred stock, shares outstanding 0 0
Common stock, par value $ 0.01 $ 0.01
Common stock, shares authorized 200,000,000 200,000,000
Common stock, shares issued 106,900,000 106,700,000
Treasury stock 700,000 700,000