Annual report pursuant to Section 13 and 15(d)

Stock-based Compensation - Awards Granted Assumptions (Detail)

v3.3.1.900
Stock-based Compensation - Awards Granted Assumptions (Detail) - $ / shares
12 Months Ended
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Risk-free interest rate 1.50% 1.30% 1.30%
Expected option life (in years) 4 years 7 months 6 days 4 years 4 months 13 days 6 years
Forfeiture rate 0.00% 0.00% 0.90%
Expected volatility 42.30% 42.80% 48.50%
Weighted-average grant date fair value (in dollars per share) $ 7.42 $ 6.44 $ 10.37
Market Based Restricted Stock      
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Risk-free interest rate 1.10% 1.10%  
Expected volatility 38.70% 43.60%