FINANCIAL INSTRUMENTS AND FAIR VALUE MEASUREMENTS (Debt) (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Carrying Value
Fair value disclosure
Debt obligations	$ 276,248	$ 291,409
Fair Value
Fair value disclosure
Debt obligations	277,568	291,560
Credit Facility | Level 2 | Carrying Value
Fair value disclosure
Debt obligations	70,000	70,000
Credit Facility | Level 2 | Fair Value
Fair value disclosure
Debt obligations	70,000	70,000
Accounts receivable securitization borrowings | Level 2 | Carrying Value
Fair value disclosure
Debt obligations	40,000	40,000
Accounts receivable securitization borrowings | Level 2 | Fair Value
Fair value disclosure
Debt obligations	40,000	40,000
Notes payable | Level 2 | Carrying Value
Fair value disclosure
Debt obligations	166,248	181,409
Notes payable | Level 2 | Fair Value
Fair value disclosure
Debt obligations	$ 167,568	$ 181,560