Inventories (Details) (USD $)	12 Months Ended
	Dec. 31, 2012 oz	Dec. 31, 2011 oz
Inventory, Net [Abstract]
Stockpiled ore	$ 33,130,000	$ 16,773,000
In-process	7,571,000	8,912,000
Materials and supplies	43,548,000	48,612,000
Finished goods	5,963,000	0
Total	90,212,000	74,297,000
Recoverable ounces of gold	45,000	36,000
Unsold ounces of gold	5,070
Material and supplies inventory written off	500,000	1,400,000
Net realizable value adjustments recorded at Bogoso	$ 100,000	$ 1,700,000