Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Operating activities:
Net income	$ 20,314	$ 2,818
Non-cash elements included in net income:
Depreciation, depletion and amortization	62,852	56,908
Loss on investments	254	117
Gain on disposition of properties, plants, equipment, and mineral interests	(166)	(94)
Provision for reclamation and closure costs	2,640	2,247
Stock compensation	2,441	2,831
Deferred income taxes	(2,977)	(22,113)
Amortization of loan origination fees	898	967
(Gain) loss on derivative contracts	(30,236)	5,386
Foreign exchange (gain) loss	(5,348)	5,201
Other non-cash items, net	(35)	2
Change in assets and liabilities:
Accounts receivable	2,471	(1,150)
Inventories	(6,865)	1,594
Other current and non-current assets	(2,507)	3,896
Accounts payable and accrued liabilities	8,701	(10,937)
Accrued payroll and related benefits	(337)	(4,901)
Accrued taxes	(672)	4,408
Accrued reclamation and closure costs and other non-current liabilities	(4,410)	(1,359)
Cash provided by operating activities	47,018	45,821
Investing activities:
Additions to properties, plants, equipment and mineral interests	(43,304)	(45,964)
Proceeds from disposition of properties, plants and equipment	463	142
Purchases of investments	(31,682)	(23,280)
Maturities of investments	59,336	14,356
Net cash used in investing activities	(15,187)	(54,746)
Financing activities:
Proceeds from sale of common stock, net of offering costs		9,610
Acquisition of treasury shares	(2,694)	(2,474)
Dividends paid to common shareholders	(2,000)	(1,981)
Dividends paid to preferred shareholders	(276)	(276)
Credit availability and debt issuance fees paid	(3)	(91)
Issuance of debt	31,024
Repayments of debt		(470)
Repayments of capital leases	(3,762)	(3,245)
Net cash provided by financing activities	22,289	1,073
Effect of exchange rates on cash	(532)	1,086
Net increase (decrease) in cash, cash equivalents and restricted cash and cash equivalents	53,588	(6,766)
Cash, cash equivalents and restricted cash and cash equivalents at beginning of period	187,139	171,977
Cash, cash equivalents and restricted cash and cash equivalents at end of period	240,727	165,211
Significant non-cash investing and financing activities:
Addition of capital lease obligations	7,008	4,645
Payment of accrued compensation in stock	$ 4,863	$ 4,240