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Stockholders' Equity and Stock-Based Compensation - Summary of Grant-Date Fair Values of Post-IPO Restricted Stock Granted and Related Assumptions (Detail) - Post-IPO Restricted Stock [Member] - $ / shares
12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Risk-free interest rates   2.20%
Risk-free interest rates, Minimum 1.28%  
Risk-free interest rates, Maximum 1.36%  
Estimated volatility   26.00%
Estimated volatility, Minimum 21.00%  
Estimated volatility, Maximum 23.00%  
Expected life (in years) 2 years 8 months 12 days 3 years 7 months 6 days
Dividend yield 0.00% 0.00%
Minimum [Member]    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Grant-date fair value of restricted stock $ 23.15 $ 21.76
Maximum [Member]    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Grant-date fair value of restricted stock $ 49.34 $ 33.33