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Weighted Average Assumptions used to Estimate Fair Value of Stock Options (Detail) - Times
12 Months Ended
Dec. 31, 2016
Dec. 26, 2015
Dec. 27, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Expected volatility 34.00% 34.20% 34.30%
Risk-free interest rate 2.16% 2.16% 2.83%
Expected dividends 0.00% 0.00% 0.00%
Exercise factor 2.68 3.00 3.40
Discount for post-vesting restrictions 0.00% 0.00% 0.00%