Equity Compensation - Fair Value (Details) - Options	12 Months Ended
	Dec. 31, 2017	Dec. 25, 2016	Dec. 27, 2015
Assumptions (weighted average):
Risk-free interest rate (as a percent)	2.00%	1.30%	1.60%
Expected dividend yield (as a percent)	1.00%	1.20%	0.90%
Expected volatility (as a percent)	26.70%	27.40%	28.50%
Expected term (in years)	5 years 7 months 6 days	5 years 6 months	5 years 6 months