Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Operating activities:
Net income (loss)	$ 26,834	$ (618)
Non-cash elements included in net income (loss):
Depreciation, depletion and amortization	29,590	26,153
Unrealized (gain) loss on investments	(327)	711
Loss on disposal of investments	167
Gain on disposition of properties, plants, equipment, and mineral interests	(32)	(210)
Provision for reclamation and closure costs	1,026	999
Stock compensation	1,349	1,231
Deferred income taxes	(21,234)	3,320
Amortization of loan origination fees	480	459
Loss on derivative contracts	7,343	170
Foreign exchange loss	506	7,989
Other non-cash gains, net	2	6
Change in assets and liabilities:
Accounts receivable	(8,738)	(20,036)
Inventories	(3,358)	(5,922)
Other current and non-current assets	1,363	(619)
Accounts payable and accrued liabilities	(1,510)	10,036
Accrued payroll and related benefits	6,881	(2,826)
Accrued taxes	1,754	(37)
Accrued reclamation and closure costs and other non-current liabilities	(3,811)	(2,058)
Cash provided by operating activities	38,285	18,748
Investing activities:
Additions to properties, plants, equipment and mineral interests	(21,658)	(34,654)
Proceeds from disposition of properties, plants and equipment	61	215
Purchases of investments	(11,113)
Maturities of investments	3,634
Addition to restricted cash for environmental matters		(3,900)
Net cash used in investing activities	(29,076)	(38,339)
Financing activities:
Proceeds from sale of common stock, net of offering costs		2,052
Acquisition of treasury shares	(731)	(1,256)
Dividends paid to common stockholders	(989)	(952)
Dividends paid to preferred stockholders	(138)	(138)
Credit facility fees paid	(91)	(59)
Repayments of debt	(470)	(664)
Repayments of capital leases	(1,595)	(2,118)
Net cash used in financing activities	(4,014)	(3,135)
Effect of exchange rates on cash	1,814	1,535
Net increase (decrease) in cash and cash equivalents	7,009	(21,191)
Cash and cash equivalents at beginning of period	169,777	155,209
Cash and cash equivalents at end of period	176,786	134,018
Significant non-cash investing and financing activities:
Addition of capital lease obligations	1,798
Payment of accrued compensation in stock	$ 4,240	$ 5,511