LONG-TERM DEBT AND FINANCING ARRANGEMENTS (Summary) (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Long-term debt obligations
Long-term debt	$ 225,450	$ 212,509
Less current portion	55,406	44,910
Long-term debt, less current portion	170,044	167,599
Payments under long-term debt obligations
Due in one year or less	59,069
Due after one year through two years	78,996
Due after two years through three years	20,453
Due after three years through four years	73,407
Due after four years through five years	2,350
Due after five years	80
Total payments	234,355
Less amounts representing interest	8,905
Long-term debt	225,450	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
Due in one year or less	$ 1,233
Due after one year through two years	1,338
Due after two years through three years	1,464
Due after three years through four years	70,796
Total payments	74,831
Less amounts representing interest	4,831
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
Due in one year or less	$ 466
Due after one year through two years	35,254
Total payments	35,720
Less amounts representing interest	720
Long-term debt	35,000	35,000
Notes payable
Long-term debt obligations
Long-term debt	$ 119,723	106,703
Weighted-average interest rate (as a percent)	2.00%
Payments under long-term debt obligations
Due in one year or less	$ 57,151
Due after one year through two years	42,180
Due after two years through three years	18,759
Due after three years through four years	2,475
Due after four years through five years	2,350
Due after five years	80
Total payments	122,995
Less amounts representing interest	3,272
Long-term debt	119,723	106,703
Capital lease obligations
Long-term debt obligations
Long-term debt	$ 727	806
Weighted-average interest rate (as a percent)	5.80%
Payments under long-term debt obligations
Due in one year or less	$ 219
Due after one year through two years	224
Due after two years through three years	230
Due after three years through four years	136
Total payments	809
Less amounts representing interest	82
Long-term debt	$ 727	$ 806