LEASES - Supplemental cash flow information (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 28, 2020	Jun. 30, 2019
LEASES
Operating cash outflow from operating leases	$ 6,315	$ 7,129
Operating cash outflow from financing leases	30	40
Financing cash outflow from financing leases	46	34
ROU assets obtained in exchange for new operating lease liabilities	$ 3,524	$ 1,999