LEASES - Aggregate future lease payments (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2019 USD ($) item	Dec. 30, 2018 USD ($)
Operating leases
2019 (remainder)	$ 10,280
2020	12,061
2021	9,898
2022	10,335
2023	10,138
2024	8,915
Thereafter	21,858
Total undiscounted cash flows	83,485
Less: imputed interest	(24,328)
Total lease liability	$ 59,157
Capital leases
Number of financing leases | item	1
Total of financing lease payments	$ 1,100	$ 1,100