Acquisitions (Details) (Wharf Gold Mine [Member], USD $)	0 Months Ended	3 Months Ended
	Feb. 20, 2015	Mar. 31, 2015	Mar. 31, 2014	Feb. 20, 2015
Wharf Gold Mine [Member]
Business Acquisition [Line Items]
Transaction costs		$ 2,000,000
Cash	103,000,000
Liabilities assumed:
Accounts payable and accrued liabilities	5,412,000			5,412,000
Reclamation	18,270,000			18,270,000
Deferred income taxes	9,503,000			9,503,000
Other non-current liabilities	3,750,000			3,750,000
Total liabilities assumed	36,935,000			36,935,000
Total consideration	139,935,000
Assets acquired:
Cash	982,000			982,000
Receivables	3,125,000			3,125,000
Inventory	2,807,000			2,807,000
Ore on leach pads	12,710,000			12,710,000
Other current assets	2,924,000			2,924,000
Property, plant, and equipment	30,054,000			30,054,000
Mining properties, net	83,367,000			83,367,000
Other non-current assets	3,966,000			3,966,000
Total assets acquired	139,935,000			139,935,000
Business Acquisition, Pro Forma Information [Abstract]
Revenue		170,956,000	178,917,000
Income (loss) before income and mining taxes		(33,271,000)	(36,673,000)
Net income (loss)		$ (33,340,000)	$ (31,957,000)