Annual report pursuant to Section 13 and 15(d)

Stock-based Expense - Additional Information (Detail)

v3.8.0.1
Stock-based Expense - Additional Information (Detail) - USD ($)
$ in Thousands
1 Months Ended 11 Months Ended 12 Months Ended
Jan. 31, 2014
Dec. 31, 2014
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Stock options granted (in shares)     0    
Stock-based expense     $ 45,835 $ 36,852 $ 38,122
Unrecognized compensation cost     $ 48,200    
Unrecognized non-vested stock awards recognition period     1 year 11 months 24 days    
Cash proceeds from stock-based compensation arrangements     $ 27,000 28,500 12,100
Aggregate intrinsic value of stock options     $ 25,100 $ 11,300 $ 5,000
Forfeiture rate         0.00%
Expected dividend rate         0.00%
Stock Option          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Vesting percentage 75.00%        
Expiration period from grant date (in years)     10 years    
Percentage of stock options to be vested during remaining period 25.00%        
Market Based Restricted Stock | Minimum          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Requisite service period (in months)     15 months 24 months  
Market Based Restricted Stock | Maximum          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Requisite service period (in months)     33 months 30 months  
Time Based Restricted Stock          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Stock options vesting period (in years) 4 years 3 years      
Aggregate grant date fair value     $ 22,600 $ 16,900 $ 21,500
Performance-Based Restricted Stock          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Requisite service period (in months)     1 year    
Common Stock          
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]          
Stock options granted (in shares)     27,634,259 27,634,259