Consolidated Statements Of Comprehensive Income (Loss) (Parentheticals) - USD ($) $ in Thousands	12 Months Ended
	Dec. 27, 2015	Dec. 28, 2014	Dec. 29, 2013
Statement of Comprehensive Income [Abstract]
Amortization of pension plan actuarial losses, tax	$ 123	$ (290)	$ 996
Change in realized and unrealized (losses) gains on derivative hedges, tax	0	0	139
Other postretirement benefit plans, tax	$ 0	$ 0	$ 0