Segment Information (Reconciliation of Segment Income) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Other (income) expense
Change in fair value of common stock purchase warrants	$ 0	$ 0.1
General and administrative	7.1	7.7
Exploration	0.1	0.8
Interest expense (income), net	0.1	1.5
(Gain) loss on foreign exchange	19.4	(6.6)
Other	0	(0.3)
(Loss) income before income and mining taxes	(2.3)	(11.0)
Income and mining tax (benefit) expense	(3.2)	(12.1)
Net income	0.9	1.1
Unallocated amount to segment
Reconciliation of segment income to net income
Segment income	18.6	(2.9)
Other (income) expense
Change in fair value of common stock purchase warrants	0	0.1
General and administrative	7.1	7.7
Exploration	0.1	0.8
Interest expense (income), net	(0.1)	1.3
(Gain) loss on foreign exchange	13.3	(2.1)
Corporate depreciation	0.5	0.6
Other	0	(0.3)
(Loss) income before income and mining taxes	(2.3)	(11.0)
Income and mining tax (benefit) expense	(3.2)	(12.1)
Net income	$ 0.9	$ 1.1