Leases - Rent Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 30, 2017	Dec. 31, 2016	Dec. 26, 2015
Leases [Abstract]
Base rentals	$ 73,597	$ 70,962	$ 70,033
Contingent rentals	31,046	30,058	30,389
Total rental income	$ 104,643	$ 101,020	$ 100,422