Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Operating activities:
Net (loss) income	$ (618)	$ 12,552
Non-cash elements included in net (loss) income:
Depreciation, depletion and amortization	26,153	25,523
Unrealized loss on investments	711	2,843
(Gain) loss on disposition of properties, plants, equipment, and mineral interests	(210)	74
Provision for reclamation and closure costs	999	778
Stock compensation	1,231	1,060
Deferred income taxes	3,320	555
Amortization of loan origination fees	459	454
Loss (gain) on derivative contracts	170	(2,970)
Foreign exchange loss (gain)	7,989	(11,490)
Other non-cash gains, net	6	24
Change in assets and liabilities:
Accounts receivable	(20,036)	(8,210)
Inventories	(5,922)	3,949
Other current and non-current assets	(619)	(1,638)
Accounts payable and accrued liabilities	10,036	4,037
Accrued payroll and related benefits	(2,826)	(5,116)
Accrued taxes	(37)	(263)
Accrued reclamation and closure costs and other non-current liabilities	(2,058)	(743)
Cash provided by operating activities	18,748	21,419
Investing activities:
Additions to properties, plants, equipment and mineral interests	(34,654)	(26,958)
Proceeds from disposition of properties, plants and equipment	$ 215	25
Purchases of investments		$ (947)
Addition to restricted cash for environmental matters	$ (3,900)
Net cash used in investing activities	(38,339)	$ (27,880)
Financing activities:
Proceeds from sale of common stock, net of offering costs	2,052
Acquisition of treasury shares	(1,256)	$ (941)
Dividends paid to common stockholders	(952)	(924)
Dividends paid to preferred stockholders	(138)	(138)
Debt origination fees	(59)	$ (63)
Repayments of debt	(664)
Repayments of capital leases	(2,118)	$ (2,347)
Net cash used in financing activities	(3,135)	(4,413)
Effect of exchange rates on cash	1,535	(2,560)
Net decrease in cash and cash equivalents	(21,191)	(13,434)
Cash and cash equivalents at beginning of period	155,209	209,665
Cash and cash equivalents at end of period	$ 134,018	196,231
Significant non-cash investing and financing activities:
Addition of capital lease obligations		1,599
Payment of accrued compensation in stock	$ 5,511	$ 3,016