DEBT (Details) (USD $) In Thousands, unless otherwise specified			1 Months Ended	12 Months Ended			1 Months Ended		12 Months Ended					12 Months Ended				1 Months Ended		12 Months Ended		12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Mar. 31, 2002 Senior Unsecured Notes due 2012, interest at 6.36% Y	Dec. 31, 2011 Senior Unsecured Notes due 2012, interest at 6.36%	Dec. 31, 2010 Senior Unsecured Notes due 2012, interest at 6.36%	Apr. 30, 2004 Senior Unsecured Notes due 2012, interest at 6.36%	Mar. 31, 2002 Senior Unsecured Notes due 2012, interest at 6.36% Minimum Y	Mar. 31, 2002 Senior Unsecured Notes due 2012, interest at 6.36% Maximum Y	Dec. 31, 2011 Senior Unsecured Notes due 2012, interest at 6.36% Interest rate swaps terminated in May 2003	Dec. 31, 2010 Senior Unsecured Notes due 2012, interest at 6.36% Interest rate swaps terminated in May 2003	Dec. 31, 2009 Senior Unsecured Notes due 2012, interest at 6.36% Interest rate swaps terminated in May 2003	May 31, 2003 Senior Unsecured Notes due 2012, interest at 6.36% Interest rate swaps terminated in May 2003	Mar. 31, 2002 Senior Unsecured Notes due 2012, interest at 6.36% Interest rate swaps terminated in May 2003	Dec. 31, 2011 Senior Unsecured Notes due 2012, interest at 6.36% Interest rate swaps terminated in February 2009	Dec. 31, 2010 Senior Unsecured Notes due 2012, interest at 6.36% Interest rate swaps terminated in February 2009	Dec. 31, 2009 Senior Unsecured Notes due 2012, interest at 6.36% Interest rate swaps terminated in February 2009	Feb. 28, 2009 Senior Unsecured Notes due 2012, interest at 6.36% Interest rate swaps terminated in February 2009	Mar. 31, 2007 Series A Notes	Mar. 31, 2009 Series B Notes	Dec. 31, 2011 Capital leases due through 2017, interest at .90% to 6.25%	Dec. 31, 2010 Capital leases due through 2017, interest at .90% to 6.25%	Dec. 31, 2011 Other borrowings due through 2023, interest up to 6.00%	Dec. 31, 2010 Other borrowings due through 2023, interest up to 6.00%
Debt
Interest rate (as a percent)				6.36%
Interest rate, low end of range (as a percent)																				0.90%
Interest rate, high end of range (as a percent)																				6.25%		6.00%
Long-term debt
Long-term debt	$ 83,456	$ 86,422		$ 80,358	$ 82,225															$ 901	$ 1,869	$ 2,197	$ 2,328
Less current portion	81,496	1,795
Total long-term debt	1,960	84,627
Total debt	103,378	97,705
Notes issued through a private placement			150,000
Weighted-average interest rate (as a percent)			6.10%	6.10%
Maturity period (in years)							5	10
Average maturity period (in years)			8
Compliance with debt covenants				As of December 31, 2011, the Company was in compliance with all of its covenants under the Notes agreement.
Notes repaid																		40,000	30,000
Outstanding balance of the Notes				80,000
Maturity date of the Notes				Mar. 01, 2012
Notional value of interest rate swaps						110,000							80,000				80,000
Unamortized deferred gain on termination of interest rate swaps									30			10,613		328			5,079
Reduction in interest expense from amortization of gain on termination of interest rate swaps									206	206	313			1,661	1,661	1,429
Interest rate swap activities				The Company has no interest rate swaps outstanding at December 31, 2011.
Amount of Series B Notes under hedge which had matured																			30,000
Weighted average effective interest rate on the Note, net of the impact of swaps (as a percent)				4.00%	4.00%
Fair value of long-term debt	84,110	88,120
Short-term debt
Amounts due banks, interest at 11.61% (17.10% in 2010)	19,922	11,283
Interest rate (as a percent)	11.61%	17.10%
Current portion of long-term debt	81,496	1,795
Total short-term debt	$ 101,418	$ 13,078
Debt issuance date				2002-03-01