LONG-TERM DEBT AND FINANCING ARRANGEMENTS (Summary) (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Long-term debt obligations
Long-term debt	$ 203,390	$ 212,509
Less current portion	45,905	44,910
Long-term debt, less current portion	157,485	167,599
Payments under long-term debt obligations
2016	49,216
2017	73,929
2018	17,622
2019	71,589
Total payments	212,356
Less amounts representing interest	8,966
Long-term debt	203,390	212,509
Credit Facility
Long-term debt obligations
Long-term debt	$ 70,000	70,000
Interest rate (as a percent)	1.70%
Payments under long-term debt obligations
2016	$ 1,294
2017	1,455
2018	1,623
2019	71,339
Total payments	75,711
Less amounts representing interest	5,711
Long-term debt	70,000	70,000
Accounts receivable securitization program
Long-term debt obligations
Long-term debt	$ 35,000	35,000
Interest rate (as a percent)	1.30%
Payments under long-term debt obligations
2016	$ 496
2017	35,428
Total payments	35,924
Less amounts representing interest	924
Long-term debt	35,000	35,000
Notes payable
Long-term debt obligations
Long-term debt	$ 97,626	106,703
Weighted-average interest rate (as a percent)	1.90%
Payments under long-term debt obligations
2016	$ 47,212
2017	36,825
2018	15,772
2019	56
Total payments	99,865
Less amounts representing interest	2,239
Long-term debt	97,626	106,703
Capital lease obligations
Long-term debt obligations
Long-term debt	$ 764	806
Weighted-average interest rate (as a percent)	5.80%
Payments under long-term debt obligations
2016	$ 214
2017	221
2018	227
2019	194
Total payments	856
Less amounts representing interest	92
Long-term debt	$ 764	$ 806