COMMITMENTS AND CONTINGENCIES (Details) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2011 Foreign exchange forward arrangements	Dec. 31, 2010 Foreign exchange forward arrangements	Dec. 31, 2009 Foreign exchange forward arrangements	Dec. 31, 2009 October, 2008	Dec. 31, 2010 October, 2009	Oct. 27, 2011 October, 2011
Exchange rate
Percentage of appreciation or depreciation of Russian ruble against US dollar	5.30%	1.00%	2.90%
Average increase in percentage of the average value of the Russian Ruble against the US Dollar against corresponding prior period	3.00%
Foreign currency exchange forward transactions
Amounts purchased							$ 48,000,000	$ 20,000,000	$ 38,000,000
Effect of forward transactions on consolidated statement of income
Foreign currency gains (losses)				$ (1,027,000)	$ 513,000	$ 1,112,000