v2.4.0.8
Stock Option Plans and Share-Based Compensation Performance based stock units (PSU) (Details) (USD $)
3 Months Ended 9 Months Ended 3 Months Ended 9 Months Ended 12 Months Ended 9 Months Ended 0 Months Ended 9 Months Ended 0 Months Ended 12 Months Ended 9 Months Ended 3 Months Ended
Sep. 30, 2013
Sep. 30, 2012
Sep. 30, 2013
Sep. 30, 2012
Sep. 30, 2013
Performance Shares [Member]
Sep. 30, 2012
Performance Shares [Member]
Sep. 30, 2013
Performance Shares [Member]
Sep. 30, 2012
Performance Shares [Member]
Dec. 31, 2011
Performance Shares [Member]
Jun. 30, 2013
Performance Shares [Member]
Dec. 31, 2012
Performance Shares [Member]
Sep. 30, 2013
PSU program year one [Member]
Performance Shares [Member]
Jan. 17, 2012
2011 PSU [Member]
Performance Shares [Member]
Mar. 05, 2013
2013 PSU [Member]
Performance Shares [Member]
Sep. 30, 2013
2013 PSU [Member]
Performance Shares [Member]
Jan. 22, 2013
2012 PSU [Member]
Performance Shares [Member]
Dec. 31, 2012
2012 PSU [Member]
Performance Shares [Member]
Sep. 30, 2013
Below the 35th percentile ranking [Member]
PSU Program Year Two [Member]
Performance Shares [Member]
Sep. 30, 2013
Below the 35th percentile ranking [Member]
2011 PSU [Member]
Performance Shares [Member]
Sep. 30, 2013
At least 50th percentile (after yr one) [Member]
PSU Program Year Two [Member]
Performance Shares [Member]
Sep. 30, 2013
Below 50th percentile ranking [Member]
PSU Program Year Two [Member]
Performance Shares [Member]
Sep. 30, 2013
Below 50th percentile ranking [Member]
2011 PSU [Member]
Performance Shares [Member]
Sep. 30, 2013
Minimum [Member]
Below the 75th percentile ranking [Member]
PSU program year one [Member]
Performance Shares [Member]
Sep. 30, 2013
Maximum [Member]
Below the 75th percentile ranking [Member]
PSU program year one [Member]
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                                                
PSU percentage eligible for time-based vesting                                   0.00% 0.00% 100.00% 50.00% 50.00% 110.00% 119.00%
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Share-based Awards Other than Options         $ 1,500,000   $ 1,500,000                                  
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition             1 year 4 months 6 days                                  
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number                   253,000 175,000                          
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value         $ 13.07   $ 13.07       $ 11.00                          
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period             140,000   100,000         12,500 125,000   125,000              
PSU shares eligible for vesting based on actual shareholder return                       120,000 120,000     62,500                
Share-based Compensation Arrangement By Share-based Payment Award, Number Of Shares Eligible For Vesting                     62,500                          
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period             38,000                                  
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value             $ 14.74                                  
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value             $ 11.02                                  
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period             24,000                                  
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value             $ 0.00                                  
Allocated Share-based Compensation Expense $ 2,810,000 $ 2,361,000 $ 8,423,000 $ 6,781,000 $ 400,000 $ 200,000 $ 1,200,000 $ 800,000                                
Percentile ranking of 2011 shareholder return                       76.30%       35.30%                
PSU percentage eligible for vesting based on actual return                         120.00%     50.00%                
Share-based Compensation Arrangement by Share-based payment Award, Percent Vested in First Year                       0.00%