SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details 2) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Provisions for depreciation
Depreciation	$ 15,112,000	$ 15,975,000	$ 15,874,000
Impairment of long-lived assets
Asset impairment, routing and scheduling initiative			$ 2,900,000
Buildings
EQUIPMENT AND PROPERTY
Useful lives of the assets, minimum (in years)	10
Useful lives of the assets, maximum (in years)	40
Furniture, fixtures, and operating equipment
EQUIPMENT AND PROPERTY
Useful lives of the assets, minimum (in years)	2
Useful lives of the assets, maximum (in years)	10