PENSION AND OTHER POSTRETIREMENT BENEFITS - Schedule of Unrecognized Benefit Amounts (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jul. 01, 2018
Pension Benefits
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Net actuarial loss (gain), beginning of period	$ 54,343	$ 54,235
Amortization	(656)	(602)
Curtailment and settlement adjustments	(1,930)	0
Actuarial loss (gain)	13,734	(9,465)
Asset loss (gain)	(9,806)	2,936
Net actuarial loss (gain), end of period	55,685	47,104
Other Benefits
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Net actuarial loss (gain), beginning of period	(34)	35
Amortization	0	0
Curtailment and settlement adjustments	0	0
Actuarial loss (gain)	96	(62)
Asset loss (gain)	0	0
Net actuarial loss (gain), end of period	$ 62	$ (27)