FINANCIAL INSTRUMENTS AND FAIR VALUE MEASUREMENTS (Debt) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Carrying Value
Fair value disclosure
Debt obligations	$ 243,032	$ 211,703
Fair Value
Fair value disclosure
Debt obligations	242,503	211,495
Level 2 | Credit Facility | Carrying Value
Fair value disclosure
Debt obligations	70,000	70,000
Level 2 | Credit Facility | Fair Value
Fair value disclosure
Debt obligations	70,000	70,000
Level 2 | Accounts receivable securitization program | Carrying Value
Fair value disclosure
Debt obligations	35,000	35,000
Level 2 | Accounts receivable securitization program | Fair Value
Fair value disclosure
Debt obligations	35,000	35,000
Level 2 | Notes payable | Carrying Value
Fair value disclosure
Debt obligations	138,032	106,703
Level 2 | Notes payable | Fair Value
Fair value disclosure
Debt obligations	$ 137,503	$ 106,495