LONG-TERM DEBT AND FINANCING ARRANGEMENTS (Summary) (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Long-term debt obligations
Long-term debt	$ 227,070	$ 243,673
Less current portion	59,995	64,143
Long-term debt, less current portion	167,075	179,530
Payments under long-term debt obligations
Due in one year or less	64,735
Due after one year through two years	44,207
Due after two years through three years	122,755
Due after three years through four years	5,310
Due after four years through five years	2,338
Total payments	239,345
Less amounts representing interest	12,275
Long-term debt	227,070	243,673
Credit Facility
Long-term debt obligations
Long-term debt	$ 70,000	70,000
Interest rate (as a percent)	2.50%
Payments under long-term debt obligations
Due in one year or less	$ 1,944
Due after one year through two years	2,275
Due after two years through three years	71,886
Total payments	76,105
Less amounts representing interest	6,105
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)	3.35%
Accounts receivable securitization program
Long-term debt obligations
Long-term debt	$ 35,000	35,000
Interest rate (as a percent)	1.70%
Payments under long-term debt obligations
Due in one year or less	$ 759
Due after one year through two years	925
Due after two years through three years	36,047
Total payments	37,731
Less amounts representing interest	2,731
Long-term debt	35,000	35,000
Notes payable
Long-term debt obligations
Long-term debt	$ 121,444	138,032
Weighted-average interest rate (as a percent)	2.20%
Payments under long-term debt obligations
Due in one year or less	$ 61,802
Due after one year through two years	40,772
Due after two years through three years	14,621
Due after three years through four years	5,303
Due after four years through five years	2,331
Total payments	124,829
Less amounts representing interest	3,385
Long-term debt	121,444	138,032
Capital lease obligations
Long-term debt obligations
Long-term debt	$ 626	641
Weighted-average interest rate (as a percent)	5.70%
Payments under long-term debt obligations
Due in one year or less	$ 230
Due after one year through two years	235
Due after two years through three years	201
Due after three years through four years	7
Due after four years through five years	7
Total payments	680
Less amounts representing interest	54
Long-term debt	$ 626	$ 641