EMPLOYEE BENEFIT PLANS - Components of Net Period Benefit Cost (Details) - Pension Plans - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 26, 2015	Dec. 27, 2014
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 2,453	$ 4,293	$ 4,155
Interest cost	12,046	12,974	13,831
Expected return on plan assets	(14,164)	(16,987)	(17,444)
Amortization of prior service cost (credit)	(292)	(581)	1,211
Amortization of net loss (gain)	2,003	3,198	23
Curtailment	(279)	0	0
Settlements	788	0	0
Net periodic cost (benefit)	$ 2,555	$ 2,897	$ 1,776