INVESTMENT IN MINERA SANTA CRUZ S.A. ("MSC") - SAN JOSE MINE - Summary of Operating Results from MSC (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended	12 Months Ended
Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
INVESTMENT IN MINERA SANTA CRUZ S.A. ("MSC") - SAN JOSE MINE
Income tax recovery	$ (2,140)	$ 153	$ (3,278)	$ (2,503)
(Loss) from investment in MSC, net of amortization	$ (2,265)	$ (263)	$ (2,477)	$ (73)
Corporate Venture
INVESTMENT IN MINERA SANTA CRUZ S.A. ("MSC") - SAN JOSE MINE
Ownership interest (as a percent)	100.00%	100.00%	100.00%	100.00%
MSC
INVESTMENT IN MINERA SANTA CRUZ S.A. ("MSC") - SAN JOSE MINE
Net sales	$ 52,272	$ 60,835	$ 102,934	$ 109,178
Production costs applicable to sales	(43,346)	(52,415)	(86,814)	(89,114)
Net (loss) income	$ (7,700)	$ (1,126)	$ (6,822)	$ 3,255
Ownership interest (as a percent)	49.00%	49.00%	49.00%	49.00%
Net income (loss)	$ (3,773)	$ (553)	$ (3,343)	$ 1,594	$ (2,328)
Amortization of fair value increments	2,482	2,428	4,597	4,497	9,632
Income tax recovery	3,990	2,718	5,463	2,830	$ 11,916
(Loss) from investment in MSC, net of amortization	$ (2,265)	$ (263)	$ (2,477)	$ (73)

Represents the amortization of fair value increments from the equity method investments.

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This item represents the entity's proportionate share for the period of the net income (loss) of its investee, before amortization, to which the equity method of accounting is applied.

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The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

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The amount of the cost of sales reported by an equity method investment of the entity.

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The amount of net income (loss) reported by an equity method investment of the entity.

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The amount of revenue from sale of goods and services reduced by sales returns, allowances, and discounts reported by an equity method investment of the entity.

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