Income Taxes Reconciliation of Effective Tax Rate (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Income Tax Disclosure [Abstract]
Net income / (loss) before minority interest	$ 6,601,000	$ 8,482,000	$ (9,128,000)
Statutory tax rate	25.00%	26.50%	28.50%
Tax expense/(benefit) at statutory rate	1,650,000	2,248,000	(2,601,000)
Foreign tax rates	(6,193,000)	(7,340,000)	(7,548,000)
Change in tax rates	(22,145,000)	3,395,000	659,000
Expired loss carryovers	6,144,000	0	0
Ghana investment allowance	300,000	(513,000)	(761,000)
Non-deductible stock options compensation	1,303,000	884,000	848,000
Non-deductible expense	270,000	376,000	543,000
Income Tax Reconciliation, Nondeductible Expense, Convertible	6,096,000	0	0
Loss carryover not previously recognized	627,000	(1,189,000)	2,321,000
Ghana property basis not previously recognized	(3,523,000)	(1,385,000)	912,000
Change in future tax assets due to exchange rates	(445,000)	738,000	(1,864,000)
Change in valuation allowance	31,932,000	10,881,000	10,907,000
National Tax Levy	0	2,669,000	1,488,000
Other	800,000	220,000	573,000
Income tax expense / (recovery)	16,816,000	10,984,000	5,477,000
Net Tax Impact Of Share Offering [Member]
Income Tax Contingency [Line Items]
Unrealized loss on investments	(2,694,000)
Tax benefit of unrealized loss on investments recorded in other comprehensive income	700,000
Valuation allowance recorded in other comprehensive income	$ (700,000)