SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Products, Properties and Production of Minerals (Details)	12 Months Ended
	Dec. 31, 2015 oz	Dec. 31, 2014 oz	Dec. 31, 2013 shares
Maximum
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
Shares issued | shares			2,500,000
Gold and Silver | El Gallo mine
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
Option to sell prior to the completion of refining (as a percent)	90.00%
Period of completion of refining	15 days
Gold and gold equivalents | El Gallo 1 mine and El Gallo 2 project | NSR royalty agreement
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
Net smelter return (as a percent)	3.50%
Quantity produced (in ounces)		212,200
Gold and gold equivalents | El Gallo 1 mine and El Gallo 2 project | Production up to 30000 ounces | NSR royalty agreement
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
Net smelter return (as a percent)	1.00%
Gold and gold equivalents | El Gallo 1 mine and El Gallo 2 project | Production up to 30000 ounces | NSR royalty agreement | Maximum
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
Production quantity used to determine net smelter return	30,000
Gold and gold equivalents | El Gallo 1 mine and El Gallo 2 project | Production between 30001 to 380000 ounces | NSR royalty agreement
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
Net smelter return (as a percent)	3.50%
Gold and gold equivalents | El Gallo 1 mine and El Gallo 2 project | Production between 30001 to 380000 ounces | NSR royalty agreement | Minimum
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
Production quantity used to determine net smelter return	30,001
Gold and gold equivalents | El Gallo 1 mine and El Gallo 2 project | Production between 30001 to 380000 ounces | NSR royalty agreement | Maximum
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
Production quantity used to determine net smelter return	380,000
Gold and gold equivalents | El Gallo 1 mine and El Gallo 2 project | Production above 380000 ounces | NSR royalty agreement
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
Net smelter return (as a percent)	1.00%