Insurance Reserves - Changes in Reserves (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 25, 2016	Dec. 27, 2015
Insurance Reserves
Balance at the beginning of the period	$ 30,550	$ 25,411
Additions	42,508	39,272
Payments	(37,615)	(34,133)
Balance at the end of the period	$ 35,443	$ 30,550