PENSION AND OTHER POSTRETIREMENT BENEFITS (Schedule of Net Defined Benefit Pension and Other Postretirement Costs) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 27, 2020	Sep. 29, 2019	Sep. 27, 2020	Sep. 29, 2019
Pension Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Interest cost	$ 1,997	$ 1,468	$ 6,047	$ 4,402
Estimated return on plan assets	(3,256)	(1,349)	(9,754)	(4,047)
Settlement loss	2,941	1,134	2,941	3,064
Other	87	0	624	0
Amortization of net loss	376	328	1,127	984
Net costs	2,145	1,581	985	4,403
Other Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Interest cost	9	13	27	39
Estimated return on plan assets	0	0	0	0
Settlement loss	0	0	0	0
Other	0	0	0	0
Amortization of net loss	0	0	0	0
Net costs	$ 9	$ 13	$ 27	$ 39