Income Taxes (Income Tax Examinations) (Details) $ in Millions	Dec. 31, 2015 USD ($)
Operating Loss Carryforwards [Line Items]
Tax Loss Carryforward	$ 148.5
UNITED STATES [Member]
Operating Loss Carryforwards [Line Items]
Tax Loss Carryforward	113.2
ZAMBIA [Member]
Operating Loss Carryforwards [Line Items]
Tax Loss Carryforward	14.4
FRANCE [Member]
Operating Loss Carryforwards [Line Items]
Tax Loss Carryforward	12.2
Others [Member]
Operating Loss Carryforwards [Line Items]
Tax Loss Carryforward	$ 8.7