| PROPERTY, PLANT AND EQUIPMENT (Narrative) (Details) - USD ($) | 12 Months Ended | ||
|---|---|---|---|
| Dec. 31, 2016 | Dec. 31, 2015 | Dec. 31, 2014 | |
| Property, Plant and Equipment [Line Items] | |||
| Depreciation | $ 106,800,000 | $ 119,200,000 | $ 173,000,000 | 
| Tangible Asset Impairment Charges | 0 | 0 | 537,800,000 | 
| Depletion | $ 3,800,000 | $ 7,400,000 | 79,600,000 | 
| Land Rights And Mineral Rights [Member] | |||
| Property, Plant and Equipment [Line Items] | |||
| Tangible Asset Impairment Charges | $ 297.2 | ||
| X | ||||||||||
| 
- Definition The noncash expense charged against earnings to recognize the consumption of natural resources. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
 | 
| X | ||||||||||
| 
- Definition The amount of expense recognized in the current period that reflects the allocation of the cost of tangible assets over the assets' useful lives. Includes production and non-production related depreciation. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
 | 
| X | ||||||||||
| 
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available. 
 | 
| X | ||||||||||
| 
- Definition The charge against earnings resulting from the aggregate write down of tangible assets from their carrying value to their fair value. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
 | 
| X | ||||||||||
| 
- Details 
 |