Quarterly report pursuant to Section 13 or 15(d)

Share Based Compensation (Details Textual)

Share Based Compensation (Details Textual) (USD $)
In Millions, except Share data, unless otherwise specified
3 Months Ended
Mar. 31, 2013
Mar. 31, 2012
Share Based Compensation (Textuals) [Abstract]    
Total fair value of awards vested $ 2.1 $ 1.1
Share Based Compensation (Additional Textuals) [Abstract]    
Typical vesting rate for options granted 3 years  
Cash received for exercises of stock options 2.5 0.4
Tax benefit realized from stock option exercises 0.2 0
Exercise of stock option 445,000  
Award vested as of grant date 100.00%  
Granted, weighted average grant date fair value per share $ 7.14 $ 5.88
Total unrecognized compensation cost related to nonvested awards $ 51.1  
Weighted-average expense recognition period 2 years 4 months  
Common stock available for future grants 34,600,000  
After May 2004 [Member]
Share Based Compensation (Textuals) [Abstract]    
Options granted, term   P7Y
Prior to May 2004 [Member]
Share Based Compensation (Textuals) [Abstract]    
Options granted, term   P10Y