Quarterly report pursuant to Section 13 or 15(d)

Income Taxes (Details Textual)

Income Taxes (Details Textual) (USD $)
3 Months Ended
Mar. 31, 2012
Mar. 31, 2011
Income Taxes (Textual) [Abstract]    
Income taxes $ 44,570,000 $ 32,733,000
Effective income tax rate 29.20% 27.10%
Estimated decrease in unrecognized tax benefit in the next twelve months 25,200,000  
Decrease in unrecognized tax benefits due to the settlement of audits or resolution of administrative or judicial proceedings 21,500,000  
Decrease in unrecognized tax benefits expiration of statute of limitations 3,700,000  
Total amount of the unrecognized tax benefits, including related interest and penalties 39,300,000  
Total accrued interest for tax contingencies 5,300,000  
Total accrued penalties for tax contingencies 1,300,000  
Unrecognized tax benefits excluding interest and penalties that if recognized would affect effective tax rate $ 32,200,000