Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Operating activities:
Net income (loss)	$ (86,968)	$ 17,824	$ (25,130)
Non-cash elements included in net income (loss):
Depreciation, depletion and amortization	112,585	112,173	82,366
Net loss (gain) on sale of investments	44		(197)
Unrealized loss on investments	3,333	3,224	2,639
Adjustment of inventory to market value	1,649
(Gain) loss on disposition of properties, plants, equipment and mineral interests	404	(25)	(75)
Provision for reclamation and closure costs	12,036	10,215	1,788
Deferred income taxes	54,978	1,895	(5,893)
Stock compensation	5,425	4,965	4,461
Amortization of loan origination fees	1,821	2,183	1,435
(Gain) loss on derivative contracts	11,630	(6,886)	(1,338)
Foreign exchange gain	(20,081)	(10,482)	(928)
Other non-cash items	(35)	(858)	636
Change in assets and liabilities, net of business acquired:
Accounts receivable	(6,834)	3,091	(1,313)
Inventories	(854)	1,119	(6,507)
Other current and non-current assets	1,195	(580)	3,281
Accounts payable and accrued liabilities	(4,211)	(19,697)	(10,927)
Accrued payroll and related benefits	7,325	16,422	539
Accrued taxes	4,653	(3,612)	(4,775)
Accrued reclamation and closure costs and other non-current liabilities	8,350	(47,847)	(13,418)
Net cash provided by operating activities	106,445	83,124	26,644
Investing activities:
Additions to properties, plants, equipment and mineral interests	(137,443)	(122,537)	(150,736)
Proceeds from sale of investments	14		1,772
Proceeds from disposition of properties, plants and equipment	579	428	460
Redemptions of restricted cash and investment balances		4,334	125
Purchases of investments	(947)	(580)	(6,001)
Purchase of a business, net of cash acquired	(809)		(321,117)
Net cash used by investing activities	(138,606)	(118,355)	(475,497)
Financing activities:
Proceeds from exercise of warrants		54,418	61
Dividends paid to common stockholders	(3,739)	(3,547)	(5,991)
Dividend paid to preferred stockholders	(552)	(552)	(552)
Debt issuance and credit facility fees paid	(127)	(938)	(1,244)
Acquisition of treasury shares	(1,874)	(3,740)	(286)
Borrowings on debt			490,000
Payments on debt	(870)
Repayments of capital leases	(9,981)	(9,137)	(7,039)
Net cash provided by (used in) financing activities	(17,143)	36,504	474,949
Effect of exchange rates on cash	(5,152)	(3,783)	(4,905)
Net increase (decrease) in cash and cash equivalents	(54,456)	(2,510)	21,191
Cash and cash equivalents at beginning of year	209,665	212,175	190,984
Cash and cash equivalents at end of year	155,209	209,665	212,175
Cash received (paid) during year for:
Interest, net of amount capitalized	(22,628)	(23,749)	(13,465)
Income tax receipts (payments)	4,186	7,124	(1,402)
Significant non-cash investing and financing activities:
Stock issued for acquisition of assets	19,133		218,302
Capital leases acquired	5,090	9,475	$ 12,344
Payment of accrued compensation in restricted stock units	$ 3,016	4,600
Senior notes contributed to pension plan, par value		$ 6,500