DEFINED BENEFIT RETIREMENT PLAN (Details 2) - USD ($) $ in Thousands	Dec. 26, 2015	Dec. 27, 2014	Dec. 28, 2013
Defined Benefit Plan Disclosure [Line Items]
Fair value pension plans	$ 518,126	$ 542,159	$ 497,460
Level 2 member
Defined Benefit Plan Disclosure [Line Items]
Fair value pension plans	518,126	542,159
Temporary cash investments
Defined Benefit Plan Disclosure [Line Items]
Fair value pension plans	5,181	12,320
Temporary cash investments | Level 2 member
Defined Benefit Plan Disclosure [Line Items]
Fair value pension plans	5,181	12,320
Index linked gilts
Defined Benefit Plan Disclosure [Line Items]
Fair value pension plans	123,257	135,229
Index linked gilts | Level 2 member
Defined Benefit Plan Disclosure [Line Items]
Fair value pension plans	123,257	135,229
Corporate bonds
Defined Benefit Plan Disclosure [Line Items]
Fair value pension plans	100,701	107,880
Corporate bonds | Level 2 member
Defined Benefit Plan Disclosure [Line Items]
Fair value pension plans	100,701	107,880
Corporate stock
Defined Benefit Plan Disclosure [Line Items]
Fair value pension plans	172,456	176,010
Corporate stock | Level 2 member
Defined Benefit Plan Disclosure [Line Items]
Fair value pension plans	172,456	176,010
Diversified growth funds
Defined Benefit Plan Disclosure [Line Items]
Fair value pension plans	116,531	110,720
Diversified growth funds | Level 2 member
Defined Benefit Plan Disclosure [Line Items]
Fair value pension plans	$ 116,531	$ 110,720