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INVENTORIES (Tables) | 12 Months Ended
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Dec. 31, 2017
Inventory Disclosure [Abstract] |
Schedule of activity in reserves for excess and obsolete inventory | The following table shows the activity in the reserves for excess and obsolete inventory (in thousands of dollars):
| For the Years Ended December 31,
| 2017 |  | 2016
Balance at beginning of period | $ | (191,514 | ) |  | $ | (168,105 | )
Provision for excess and obsolete inventory | (24,829 | ) |  | (58,485 | )
Disposal of unsaleable inventory | 29,442 |  |  | 30,161 |
Other | (6,547 | ) |  | 4,915 |
Balance at end of period | $ | (193,448 | ) |  | $ | (191,514 | )

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