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INVESTMENTS (Details) $ in Thousands |  |  | 12 Months Ended
--- | --- | --- | ---
Jul. 21, 2016 USD ($) item | May 13, 2016 USD ($) item | Dec. 31, 2017 USD ($) | Dec. 31, 2016 USD ($) | Dec. 31, 2015 USD ($)
Investments rollforward |  |  |  |  |
Opening balance |  |  | $ 8,543 | $ 1,032 |
Additions during the year |  |  |  | 4,419 |
Disposals during the period |  |  | (2,163) | (470) |
Other Comprehensive Income (Loss) (pre -tax) |  |  | 1,334 | 3,043 |
Statement of Operations (Loss) Income |  |  | 257 | 519 |
Fair Value end of the year |  |  | 7,971 | 8,543 | $ 1,032
Fair value Available for Sale |  |  |  |  |
Opening balance |  |  | 8,543 |  |
Additions during the period |  |  |  | 4,419 | 1,114
Disposals during the period |  |  | (2,155) | (470) |
Fair Value end of the period |  |  | 7,971 | 8,543 |
Fair value of warrants |  |  |  |  |
Cost of purchase of marketable equity securities |  |  | 3,300 | 4,900 |
Unrealized (loss) gain on derivatives (note 3) |  |  | (227) | 1,379 |
Unrealized gain on available-for-sale securities |  |  | 1,800 |  |
Gain on available-for-sale securities, pre-tax |  |  | 800 | 100 |
Other-than-temporary impairment on marketable equity securities (note 2) |  |  | (356) | (882) |
Unrealized loss on available-for-sale securities |  |  |  | 1,600 |
Sale of marketable securities |  |  | 2,200 | 500 |
Other-than-temporary impairment on marketable equity securities |  |  | 356 | 882 |
Golden Predator Mining Corporation |  |  |  |  |
Fair value of warrants |  |  |  |  |
Number of units acquired | item | 1,500,000 | 3,125,000 |  |  |
Common shares per unit | item | 1 | 1 |  |  |
Warrants per unit | item | 0.50 | 1 |  |  |
Payments For Purchase Of Private Placement | $ 900 | $ 400 |  |  |
Common Stock | Golden Predator Mining Corporation |  |  |  |  |
Fair value of warrants |  |  |  |  |
Payments For Purchase Of Private Placement | 700 | $ 200 |  |  |
Warrants |  |  |  |  |
Fair value of warrants |  |  |  |  |
Statement of Operations (Loss) Income |  |  |  |  | 0
Warrants | Golden Predator Mining Corporation |  |  |  |  |
Fair value of warrants |  |  |  |  |
Payments For Purchase Of Private Placement | $ 200 |  |  |  |
Marketable equity securities |  |  |  |  |
Fair value Available for Sale |  |  |  |  |
Opening balance |  |  | 6,749 | 1,032 |
Additions during the period |  |  |  | 4,004 |
Disposals during the period |  |  | (2,163) | (470) |
Other Comprehensive Income (Loss) (pre -tax) |  |  | 1,334 | 3,043 |
Statement of Operations (Loss) Income |  |  | 484 | (860) |
Fair Value end of the period |  |  | 6,404 | 6,749 | $ 1,032
Warrants |  |  |  |  |
Fair value Available for Sale |  |  |  |  |
Additions during the period |  |  |  | 415 |
Fair value of warrants |  |  |  |  |
Opening balance |  |  | 1,794 |  |
Statement of Operations (Loss) Income |  |  | (227) | 1,379 |
Fair Value end of the year |  |  | $ 1,567 | $ 1,794 |

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