LONG-TERM DEBT AND FINANCING ARRANGEMENTS (Summary) (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Long-term debt obligations
Long-term debt	$ 237,614	$ 212,509
Less current portion	61,251	44,910
Long-term debt, less current portion	176,363	167,599
Payments under long-term debt obligations
Due in one year or less	65,493
Due after one year through two years	82,514
Due after two years through three years	21,005
Due after three years through four years	74,909
Due after four years through five years	3,632
Due after five years	24
Total payments	247,577
Less amounts representing interest	9,963
Long-term debt	237,614	212,509
Credit Facility
Long-term debt obligations
Long-term debt	70,000	70,000
Payments under long-term debt obligations
Due in one year or less	1,514
Due after one year through two years	1,683
Due after two years through three years	1,768
Due after three years through four years	70,466
Total payments	75,431
Less amounts representing interest	5,431
Long-term debt	70,000	70,000
Credit Facility | Interest rate swap agreement
Long-term debt obligations
Amount of borrowings covered by the interest rate swap	$ 50,000
Effective fixed interest rate on hedged borrowings (as a percent)	3.10%
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	$ 532
Due after one year through two years	35,149
Total payments	35,681
Less amounts representing interest	681
Long-term debt	35,000	35,000
Notes payable
Long-term debt obligations
Long-term debt	$ 131,882	106,703
Weighted-average interest rate (as a percent)	2.10%
Payments under long-term debt obligations
Due in one year or less	$ 63,177
Due after one year through two years	45,457
Due after two years through three years	19,007
Due after three years through four years	4,365
Due after four years through five years	3,632
Due after five years	24
Total payments	135,662
Less amounts representing interest	3,780
Long-term debt	131,882	106,703
Capital lease obligations
Long-term debt obligations
Long-term debt	$ 732	806
Weighted-average interest rate (as a percent)	5.80%
Payments under long-term debt obligations
Due in one year or less	$ 270
Due after one year through two years	225
Due after two years through three years	230
Due after three years through four years	78
Total payments	803
Less amounts representing interest	71
Long-term debt	$ 732	$ 806