XML 100 R82.htm IDEA: XBRL DOCUMENT v3.8.0.1
Stock-Based Compensation - Assumptions in Determining Fair Value of Options Granted (Details) - Employee Stock Option [Member]
12 Months Ended
Dec. 30, 2017
Dec. 31, 2016
Dec. 26, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]      
Expected term 7 years 8 months 12 days 6 years 8 months 12 days 5 years 6 months
Expected price volatility 28.90% 25.60% 26.20%
Risk-free interest rate 2.10% 1.60% 1.70%
Dividend yield 1.30% 1.00% 0.90%