Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Operating activities:
Net income	$ 4,230	$ 49,285
Non-cash elements included in net income:
Depreciation, depletion and amortization	87,634	83,900
Loss on disposition of investments	167
Unrealized loss (gain) on investments	73	(488)
Gain on disposition of properties, plants, equipment, and mineral interests	(4,924)	(319)
Provision for reclamation and closure costs	3,379	3,685
Stock compensation	4,943	4,814
Acquisition costs		1,048
Deferred income taxes	(24,280)	10,330
Amortization of loan origination fees	1,415	1,397
Loss on derivative contracts	16,718	337
Foreign exchange loss	11,171	7,555
Other non-cash items, net	(1)	5
Change in assets and liabilities, net of business acquisitions:
Accounts receivable	4,903	5,776
Inventories	(9,611)	(44)
Other current and non-current assets	(2,685)	(539)
Accounts payable and accrued liabilities	(7,759)	2,042
Accrued payroll and related benefits	(913)	8,621
Accrued taxes	(4,469)	(2,894)
Accrued reclamation and closure costs and other non-current liabilities	(5,876)	(1,397)
Cash provided by operating activities	74,115	173,114
Investing activities:
Additions to properties, plants, equipment and mineral interests	(70,390)	(120,236)
Acquisitions of other companies, net of cash acquired		(3,931)
Proceeds from disposition of properties, plants, equipment and mineral interests	151	348
Insurance proceeds received for damaged property	5,628
Purchases of investments	(36,916)	(32,847)
Maturities of investments	31,169	7,240
Changes in restricted cash and investment balances	1,124	(3,900)
Net cash used in investing activities	(69,234)	(153,326)
Financing activities:
Proceeds from sale of common stock, net of offering costs	9,610	8,121
Acquisition of treasury shares	(2,993)	(4,363)
Dividends paid to common shareholders	(2,978)	(2,882)
Dividends paid to preferred shareholders	(414)	(414)
Credit availability and debt issuance fees	(476)	(107)
Repayments of debt	(470)	(1,807)
Repayments of capital leases	(5,065)	(6,328)
Net cash used in financing activities	(2,786)	(7,780)
Effect of exchange rates on cash	1,051	627
Net increase in cash and cash equivalents	3,146	12,635
Cash and cash equivalents at beginning of period	169,777	155,209
Cash and cash equivalents at end of period	172,923	167,844
Significant non-cash investing and financing activities:
Addition of capital lease obligations	6,439	2,297
Common stock issued for the acquisition of other companies		48,109
Payment of accrued compensation in restricted stock units	$ 4,240	$ 5,511