v2.4.0.6
Long Term Compensation (Details Textual) (USD $)
12 Months Ended
Dec. 31, 2011
SavingsPlans
Y
NonqualifiedSavingsPlan
Dec. 31, 2010
Dec. 31, 2009
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Performance shares granted     370,320
Unrecognized compensation cost $ 8,500,000    
Remaining weighted average period 1.3    
Vesting Period three-or four year period    
Shares earned     455,276
CPSs outstanding shares 124,278    
Unrecognized compensation cost 8,500,000    
Number of common stocks are authorized for issuance 35,900,000    
Number of savings plans 2    
Long Term Compensation (Textual) [Abstract]      
Merger conversion rate 44.64%    
Number of share option granted 0 0 0
Common stocks available for future issuance 4,900,000    
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition 1.3    
Allocated share based compensation expenses 31,500,000 25,100,000 17,200,000
Vesting Based on Employee's Years of service 20% vesting each year of service    
Vesting percentage on defined contribution plan 20.00%    
Percentage of employees annual compensation up to certain levels 3.00%    
Compensation cost related to employees contribution plans 1,600,000 1,300,000 1,100,000
Net of expenses included in share based compensation expenses 8,700,000 5,300,000 5,800,000
Employer contribution for every dollar 0.50    
Percentage of employees annual compensation within the statutory compensation limit 6.00%    
Defined contribution plan service period 5 years    
Percentage of sum of deferrals under savings plan and trust and nonqualified savings plan 50.00%    
Number of non qualified savings plan 2    
Maximum contractual term of stock option 10    
Vesting period for acquired plan 1 year    
Restricted Stock Units (RSUs) [Member]
     
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Vesting Period 3 years 3 years  
Restricted stock awards (RSAs) [Member]
     
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Minimum vesting period for RSAs P3Y    
Maximum vesting period for RSAs P4Y    
Stock Appreciation Rights [Member]
     
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Maximum limit of stocks granted 500,000    
Performance based shares granted [Member]
     
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Maximum limit of stocks granted 500,000    
Performance Share Awards [Member]
     
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Performance shares granted 280,525 242,406  
Vesting Period over 3 year    
Performance Condition, Lower Range 0.00% 0.00%  
Performance Condition, Upper Range 200.00% 200.00%  
Weighted average fair value of RSUs and deferred stock awards granted $ 32.77 $ 30.65 $ 15.52
Shares earned 326,475 225,943  
Performance period 1 year 1 year  
Cash Incentives Awards Granted [Member]
     
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Cash incentives awards granted amount maximum 10,000,000    
Restricted Stock Units, Contingent Performance Shares and Performance Shares Awards [Member]
     
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Performance shares granted 15,500    
Unrecognized compensation cost 47,100,000    
Remaining weighted average period 1.6    
Weighted average fair value of RSUs and deferred stock awards granted $ 34.07 $ 0.00  
Unrecognized compensation cost $ 47,100,000    
Long Term Compensation (Textual) [Abstract]      
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition 1.6    
Restricted Stock Awards and Deferred Stock Awards [Member]
     
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Weighted average fair value of RSUs and deferred stock awards granted $ 29.81 $ 27.58 $ 14.61
2002 long-term incentive plan [Member]
     
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Maximum limit of stocks granted 1,000,000