v2.4.0.8
Earnings Per Share (Narrative) (Details) (USD $)
In Millions, except Share data, unless otherwise specified
 3 Months Ended 9 Months Ended 3 Months Ended 9 Months Ended 3 Months Ended 9 Months Ended
Sep. 30, 2013
Sep. 30, 2012
Sep. 30, 2013
Sep. 30, 2012
Dec. 31, 2012
Sep. 30, 2013
2.50% convertible senior notes due August 15, 2013 [Member]
Mar. 31, 2008
2.50% convertible senior notes due August 15, 2013 [Member]
Sep. 30, 2013
Restricted stock and PSU's [Member]
Sep. 30, 2012
Restricted stock and PSU's [Member]
Sep. 30, 2013
Restricted stock and PSU's [Member]
Sep. 30, 2012
Restricted stock and PSU's [Member]
Sep. 30, 2013
Stock Options [Member]
Sep. 30, 2012
Stock Options [Member]
Sep. 30, 2013
Stock Options [Member]
Sep. 30, 2012
Stock Options [Member]
Sep. 30, 2013
Common stock [Member]
Sep. 30, 2012
Common stock [Member]
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]                                  
Stock options to purchase shares 5,653,638 [1]   5,653,638 [1]   7,545,777 [1]     6,407,977 6,268,114 6,407,977 6,268,114         5,653,638 9,299,981
Weighted average number diluted shares outstanding 3,773,791 4,284,300 3,854,863 3,970,984       4,826,614 6,205,162 4,567,960 5,066,223 4,397,210 6,048,811 4,397,210 6,047,125    
Incremental common shares attributable to conversion of debt securities       20,891 [2]                          
Debt instrument, interest rate           2.50% 2.50%                    
Debt instrument, principal outstanding             $ 475.0                    
[1] No stock option awards were granted during the three and nine months ended September 30, 2013.
[2] In June 2012, the remaining $0.5 million of our 3.75% convertible notes outstanding was converted into 34,482 shares of common stock in accordance with the terms of the notes.