MAMMOTH COMPLEX ACQUISITION - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended		3 Months Ended	7 Months Ended	9 Months Ended		9 Months Ended	3 Months Ended	9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2010 Mammoth Pacific	Aug. 01, 2010 Mammoth Pacific	Sep. 30, 2010 Mammoth Pacific	Aug. 02, 2010 Mammoth Pacific	Sep. 30, 2011 Mammoth Pacific Minimum acre	Sep. 30, 2011 Mammoth Complex	Sep. 30, 2011 Mammoth Complex
Business Acquisition [Line Items]
Acquired ownership interest								50.00%
Business acquisition purchase price in cash								$ 72,500,000
Ownership interest prior to acquisition						50.00%
Undeveloped federal lands									10,000
Fair value of previously held equity interest								64,900,000
Control premium of previously held equity interest								7,600,000
Gain on acquisition of controlling interest		36,928,000		36,928,000	36,900,000		36,900,000
Revenues										5,257,000	14,696,000
Net income (loss)	$ 866,000	$ 32,459,000	$ 24,000	$ 32,860,000		$ 998,000				$ 597,000	$ 1,029,000