Annual report pursuant to Section 13 and 15(d)

Share-Based and Cash-Based Incentive Compensation - Additional Information (Detail)

v2.4.0.8
Share-Based and Cash-Based Incentive Compensation - Additional Information (Detail) (USD $)
In Millions, except Share data, unless otherwise specified
12 Months Ended
Dec. 31, 2013
Dec. 31, 2012
Dec. 31, 2011
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Common stock available for award under plans 5,078,983    
Additional shares authorized under share based compensation arrangements 4,000,000    
Directors Compensation Plan
     
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Common stock available for award under plans 519,379    
Restricted Stock
     
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Shares granted, grant date fair value $ 0.3 $ 0.4 $ 0.5
Shares vested, vested date fair value 0.4 0.5 7.9
Unrecognized share-based compensation expense 0.5    
Recognition period for unrecognized compensation expense 2016-04    
Restricted Stock Units (RSUs)
     
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Shares granted, grant date fair value 12.8 14.3 14.4
Shares vested, vested date fair value 7.2 20.0  
Adjusted EBITDA 40.00%    
Adjusted EBITDA margin 30.00%    
TSR ranking totaled 30.00% 30.00%  
TSR ranking for each of three-year performance periods 10.00% 10.00%  
EPS comprised   70.00%  
Unrecognized share-based compensation expense $ 12.1    
Recognition period for unrecognized compensation expense 2015-11    
Restricted Stock Units (RSUs) | LIBOR
     
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Risk-free interest rate, minimum 0.27% 0.15%  
Risk-free interest rate, maximum 0.91% 0.72%  
Restricted Stock Units (RSUs) | Minimum
     
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Expected volatility 30.00% 33.00%  
Expected dividend yield 0.00% 0.00%  
Correlation of movement of total shareholder return (84.00%) (67.00%)  
Restricted Stock Units (RSUs) | Maximum
     
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]      
Expected volatility 63.00% 74.00%  
Expected dividend yield 3.10% 2.50%  
Correlation of movement of total shareholder return 95.00% 94.00%