FAIR VALUE OF FINANCIAL ASSETS AND LIABILITIES - Narrative (Details) $ in Thousands	Dec. 31, 2018 USD ($)	Jan. 01, 2018 USD ($)
Discounted cash flow | Fair Value, Inputs, Level 3 | Annualized EBITDA and probability of achievement
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liability for contingent consideration	$ 4,319
Discount rate	0.073
ASI
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liability for contingent consideration		$ 4,600
ASI | Other Current and Long-term Liabilities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liability for contingent consideration	$ 4,300