Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Operating activities:
Net income (loss)	$ 49,285	$ (24,005)
Non-cash elements included in net income (loss):
Depreciation, depletion and amortization	83,900	81,475
Unrealized (gain) loss on investments	(488)	3,226
(Gain) loss on disposition of properties, plants, equipment, and mineral interests	(319)	175
Provision for reclamation and closure costs	3,685	11,028
Stock compensation	4,814	4,036
Acquisition costs	1,048
Deferred income taxes	10,330	(1,781)
Amortization of loan origination fees	1,397	1,365
Loss on derivative contracts	337	9,561
Foreign exchange loss (gain)	7,555	(17,566)
Other non-cash items, net	5	45
Change in assets and liabilities, net of business acquisitions:
Accounts receivable	5,776	(2,951)
Inventories	(44)	4,382
Other current and non-current assets	(539)	(6,779)
Accounts payable and accrued liabilities	2,042	3,986
Accrued payroll and related benefits	8,621	2,221
Accrued taxes	(2,894)	2,782
Accrued reclamation and closure costs and other non-current liabilities	(1,397)	7,934
Cash provided by operating activities	173,114	78,968
Investing activities:
Additions to properties, plants, equipment and mineral interests	(120,236)	(95,399)
Acquisitions of other companies, net of cash acquired	(3,931)	(809)
Proceeds from disposition of properties, plants, equipment and mineral interests	348	277
Purchases of investments	(32,847)	(947)
Maturities of investments	7,240
Changes in restricted cash and investment balances	(3,900)
Net cash used in investing activities	(153,326)	(96,878)
Financing activities:
Proceeds from sale of common stock, net of offering costs	8,121
Acquisition of treasury shares	(4,363)	(1,875)
Dividends paid to common shareholders	(2,882)	(2,796)
Dividends paid to preferred shareholders	(414)	(414)
Credit availability and debt issuance fees	(107)	(123)
Repayments of debt	(1,807)	(216)
Repayments of capital leases	(6,328)	(7,833)
Net cash used in financing activities	(7,780)	(13,257)
Effect of exchange rates on cash	627	(4,044)
Net increase (decrease) in cash and cash equivalents	12,635	(35,211)
Cash and cash equivalents at beginning of period	155,209	209,665
Cash and cash equivalents at end of period	167,844	174,454
Significant non-cash investing and financing activities:
Addition of capital lease obligations	2,297	4,346
Common stock issued for the acquisition of other companies	48,109	19,133
Payment of accrued compensation in restricted stock units	$ 5,511	$ 3,016