FAIR VALUE MEASUREMENTS - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2009	Dec. 31, 2011 Level 3	Dec. 31, 2011 Fair Value, Measurements, Recurring Physical Fixed Price Derivative Contracts Level 2	Dec. 31, 2010 Fair Value, Measurements, Recurring Physical Fixed Price Derivative Contracts Level 2
Derivative [Line Items]
Level 2 fixed-price contracts assets, net of CVA				$ 5,292,000	$ 1,522,000
Level 2 fixed-price contracts assets, CVA				(100,000)	(100,000)
Goodwill impairment charge	169,560,000		169,560,000
Asset impairment charge		$ 59,724,000