XML 68 R57.htm IDEA: XBRL DOCUMENT v3.4.0.3
Stock-Based Compensation - Weighted-Average Assumptions Utilized to Value Stock Options (Detail) - USD ($)
3 Months Ended 6 Months Ended
Mar. 26, 2016
Mar. 28, 2015
Mar. 26, 2016
Mar. 28, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Risk-free interest rate 1.60% 1.70% 1.60% 1.70%
Expected volatility 37.80% 38.60% 37.80% 38.60%
Expected life (in years) 4 years 8 months 5 years 3 months 3 days 4 years 8 months 5 years 4 months
Dividend yield $ 0 $ 0 $ 0 $ 0
Weighted average fair value of options granted $ 11.80 $ 10.36 $ 12.98 $ 9.55