Annual report pursuant to Section 13 and 15(d)

Stock Incentive Plans - Summary of Weighted Average Assumptions (Details)

v3.8.0.1
Stock Incentive Plans - Summary of Weighted Average Assumptions (Details) - Stock Options - USD ($)
$ / shares in Units, $ in Thousands
12 Months Ended
Dec. 31, 2017
Dec. 25, 2016
Dec. 27, 2015
Weighted average assumptions used in estimation of fair value of options      
Risk-free interest rate (as a percent) 1.80% 1.20% 1.40%
Expected years until exercise 4 years 11 months 26 days 4 years 5 months 26 days 4 years 9 months 18 days
Expected stock volatility (as a percent) 37.90% 39.00% 40.60%
Dividend yield (as a percent) 0.00% 0.00% 0.00%
Weighted average Black-Scholes fair value per share at date of grant (in dollars per share) $ 17.11 $ 20.45 $ 29.71
Total intrinsic value of options exercised $ 1,676 $ 2,624 $ 4,414