STOCKHOLDERS' EQUITY (Schedule of Changes in Unrealized Actuarial Losses) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended			6 Months Ended
	Jun. 29, 2014	Jun. 30, 2013		Jun. 29, 2014	Jun. 30, 2013
Accumulated Other Comprehensive Income (Loss), Net Of Tax [Roll Forward]
Balance, beginning of period				$ (45,735)
Other comprehensive income (loss) before reclassifications				(9,363)
Amounts reclassified from accumulated other comprehensive loss to net income				(81)
Net current period other comprehensive income (loss)	(3,622)	25,391		(9,444)	35,801
Balance, end of period	(55,179)			(55,179)
Losses Related to Pension and Other Postretirement Benefits [Member]
Accumulated Other Comprehensive Income (Loss), Net Of Tax [Roll Forward]
Balance, beginning of period				(45,797)	(68,511)	[1]
Other comprehensive income (loss) before reclassifications				(9,432)	35,300	[1]
Amounts reclassified from accumulated other comprehensive loss to net income				17	501	[1]
Net current period other comprehensive income (loss)				(9,415)	35,801	[1]
Balance, end of period	(55,212)	(32,710)	[1]	(55,212)	(32,710)	[1]
Unrealized Holding Gains on Available-for-Sale Securities [Member]
Accumulated Other Comprehensive Income (Loss), Net Of Tax [Roll Forward]
Balance, beginning of period				62
Other comprehensive income (loss) before reclassifications				69
Amounts reclassified from accumulated other comprehensive loss to net income				(98)
Net current period other comprehensive income (loss)				(29)
Balance, end of period	$ 33			$ 33

[1] All amounts are net of tax. Amounts in parentheses indicate debits to accumulated other comprehensive loss.