Amount of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI).

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Amount of investment in marketable security.

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-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
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Fair value portion of physical assets used in the normal conduct of business to produce goods and services and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

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Amount of transfers of financial instruments classified measured on a recurring basis between the fair value hierarchy level 1, level 2 and level 3.

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Fair Value Accounting (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Fair Value Accounting
Other investments	$ 5,462	$ 3,746
Fair Value Transfers Between Levels		0
Midas Gold Shares
Fair Value Accounting
Other investments	5,462	3,746	$ 4,994
Recurring \| Marketable Securities (Other Than Midas Gold Shares)
Fair Value Accounting
Marketable securities		90
Recurring \| Midas Gold Shares
Fair Value Accounting
Other investments	5,462	3,746
Recurring \| Fair Value, Inputs, Level 1 \| Marketable Securities (Other Than Midas Gold Shares)
Fair Value Accounting
Marketable securities		90
Recurring \| Fair Value, Inputs, Level 1 \| Midas Gold Shares
Fair Value Accounting
Other investments	5,462	3,746
Non-recurring \| Used mill equipment, Canada
Fair Value Accounting
Used mill equipment (non-recurring)	5,500	6,500
Non-recurring \| Fair Value, Inputs, Level 3 \| Used mill equipment, Canada
Fair Value Accounting
Used mill equipment (non-recurring)	$ 5,500	$ 6,500