Organization and Summary of Significant Accounting Policies (Details)	0 Months Ended	1 Months Ended
	Nov. 14, 2011 jointventures	Oct. 19, 2011
Description of Business
Number of joint-venture surface mines	2
Reverse stock split ratio (in shares)		15
Montana
Description of Business
Number of joint-venture surface mines	1
Percentage of ownership of common stock in a joint-venture (as a percent)	50.00%
Wyoming
Description of Business
Number of joint-venture surface mines	1
Percentage of ownership of common stock in a joint-venture (as a percent)	50.00%