v2.4.0.6
Share-Based Compensation - Range of Assumptions Used and Resulting Weighted-Average Fair Value of Options Granted at Date of Grant (Detail) (USD $)
3 Months Ended 9 Months Ended
Sep. 29, 2012
Oct. 01, 2011
Sep. 29, 2012
Oct. 01, 2011
Range of assumptions used and resulting weighted-average fair value of options granted at the date of grant        
Risk-free interest rate, minimum 0.70% 1.00% 0.70% 1.00%
Risk-free interest rate, maximum 1.00% 1.90% 1.30% 2.50%
Expected term, years 5 years 6 months 5 years 3 months 18 days 5 years 6 months 5 years 3 months 18 days
Estimated volatility, minimum 36.80% 36.70% 36.80% 36.70%
Estimated volatility, maximum 37.80% 41.80% 42.60% 41.80%
Expected dividends 0.00% 0.00% 0.00% 0.00%
Weighted average fair value of option granted $ 8.41 $ 10.34 $ 8.10 $ 11.50