CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 29, 2017	Dec. 30, 2016	Dec. 25, 2015
Statement of Comprehensive Income [Abstract]
Net Earnings	$ 252,412	$ 40,674	$ 345,713
Components of other comprehensive income (loss)
Cumulative translation adjustment	16,443	(31,227)	(10,423)
Pension and postretirement medical liability adjustment	(3,321)	(10,715)	10,372
Income taxes - pension and postretirement medical liability	1,317	4,211	(3,710)
Other comprehensive income (loss)	14,439	(37,731)	(3,761)
Comprehensive Income	$ 266,851	$ 2,943	$ 341,952