Annual report pursuant to Section 13 and 15(d)

Share-Based Compensation (Details Textual)

v2.4.0.6
Share-Based Compensation (Details Textual) (USD $)
12 Months Ended 1 Months Ended 12 Months Ended
Dec. 31, 2011
Plans
Dec. 31, 2010
Dec. 31, 2009
Dec. 31, 2011
Stock Appreciation Rights (SARS) [Member]
Dec. 31, 2011
Stock Options [Member]
Dec. 31, 2011
Market Condition Awards [Member]
Y
Dec. 31, 2010
Market Condition Awards [Member]
Dec. 31, 2009
Market Condition Awards [Member]
Dec. 31, 2011
Service Condition Awards [Member]
Y
Dec. 31, 2010
Service Condition Awards [Member]
Dec. 31, 2009
Service Condition Awards [Member]
Dec. 31, 2011
Market And Performance Condition Awards [Member]
Y
Dec. 31, 2011
Incentive Plan Stock Units [Member]
Mar. 31, 2008
Market Condition 1 [Member]
Mar. 31, 2008
Market Condition Target 2 [Member]
Mar. 31, 2008
Chairman and Chief Executive Officer [Member]
Mar. 31, 2008
Chairman and Chief Executive Officer [Member]
Stock Units [Member]
Dec. 31, 2011
Independent Director [Member]
Stock Units [Member]
Dec. 31, 2011
Incentive Plan Stock Units Other [Member]
Dec. 31, 2011
Incentive Plan Stock Units Other [Member]
Stock Appreciation Rights (SARS) [Member]
Dec. 31, 2011
Incentive Plan Stock Units Other [Member]
Incentive Plan Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                                          
Company granted SARS subject to service, market and performance 25,000     900,000                                  
Contractual term       10 years 10 years               3 years                
Vesting Period beginning from the grant date       5 years 5 years                       4 years   5 years 3 years 3 years
Stock units vesting rate                                   25.00%      
Stock units vesting rate during first three years                                 30.00%        
Stock units vesting rate during fourth year                                 10.00%        
Granted Stock unit awards to chairman and Chief Executive Officer vesting                               Over a four year period at a rate of 30% during each of the first three years and 10% during the Fourth year          
Stock price appreciation rate                           10.00% 15.00%            
Weighted-average grant date fair value of SARs granted $ 42.82               $ 21.23 $ 9.32 $ 2.04 $ 17.37                  
Share-based compensation expense           $ 2,900,000 $ 3,000,000 $ 2,700,000 $ 19,200,000 $ 20,000,000 $ 18,400,000 $ 1,400,000                  
Unrecognized compensation cost on nonvested stock awards           700,000     34,100,000     11,700,000                  
Unrecognized compensation cost on nonvested stock awards, weighted-average period of recognition           0.2     1.5     3.0                  
Outstanding market and performance condition SARs 717,600 1,160,500       1,500,000 1,500,000         900,000                  
Total intrinsic value of awards exercised for options and SARs 133,800,000 63,800,000 16,400,000                                    
Percent of fair market value for which eligible employees can purchase common shares under employee stock purchase plan 85.00%                                        
Share-Based Compensation (Textual) [Abstract]                                          
Number of share based compensation plan 5                                        
Common shares remain for future issuance under share based compensation plans 5,100,000                                        
Common shares authorized under 2005 Stock Incentive Plan 14,400,000                                        
Realized Income tax benefit for all awards 7,500,000 7,400,000 7,900,000                                    
Excess tax benefit 27,450,000 8,045,000 3,587,000                                    
Total vesting date fair value of stock units $ 19,800,000 $ 10,300,000 $ 4,300,000                                    
Reserved for issuance under employee stock purchase plan 2,000,000                                        
Future Issuance of employee stock purchase plan 1,900,000