Quarterly report pursuant to Section 13 or 15(d)

Share-Based Compensation (Details)

v2.4.0.6
Share-Based Compensation (Details) (USD $)
In Millions, unless otherwise specified
3 Months Ended
Mar. 31, 2012
Mar. 31, 2011
Mar. 31, 2012
1997 Plan and 2003 Plan [Member]
Y
Dec. 31, 2011
1997 Plan and 2003 Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost $ 2.3 $ 8.0    
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized     $ 7.5 $ 7.7
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Recognition Period     4  
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition     2.2