EARNINGS PER SHARE (Details) - USD ($) $ / shares in Units, shares in Thousands	3 Months Ended											12 Months Ended
	Dec. 31, 2015		Sep. 30, 2015	Jun. 30, 2015	[1]	Mar. 31, 2015	[2]	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount												200	200
Net Income (Loss) Attributable to Parent	$ (51,160,000)		$ (31,476,000)	$ 6,771,000		$ 232,000		$ (53,046,000)	$ (9,067,000)	$ (20,511,000)	$ 2,163,000	$ (75,633,000)	$ (80,461,000)	$ 35,205,000
Noncontrolling Interest, Change in Redemption Value												(17,668,000)	(49,277,000)	0
Net Income (Loss) Available to Common Stockholders, Basic												(93,301,000)	(129,738,000)	35,205,000
Dilutive Securities, Effect on Basic Earnings Per Share												0.00	0.00	2,600,000.00
Net Income (Loss) Available to Common Stockholders, Diluted												$ (93,301,000)	$ (129,738,000)	$ 37,805,000
Weighted Average Number of Shares Outstanding, Basic												53,696	53,497	53,039
Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements												0	0	258
Incremental Common Shares Attributable to Dilutive Effect of Conversion of Debt Securities													0	6,225
Weighted Average Number of Shares Outstanding, Diluted												53,696	53,497	59,522
Earnings Per Share, Basic	$ (1.07)	[3]	$ (0.79)	$ 0.17		$ (0.05)		$ (1.58)	$ (0.47)	$ (0.40)	$ 0.02	$ (1.74)	$ (2.43)	$ 0.66
Earnings Per Share, Diluted	$ (1.07)	[3]	$ (0.79)	$ 0.17		$ (0.05)		$ (1.58)	$ (0.47)	$ (0.40)	$ 0.02	$ (1.74)	$ (2.43)	$ 0.64
5.625% convertible senior subordinated notes [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Incremental Common Shares Attributable to Dilutive Effect of Conversion of Debt Securities												5,600	5,600

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[2] (a) Mining asset impairment and inventory write-down of 34.8 million was included in the quarter ended June 30, 2014.

[3] {F|ahBzfndlYmZpbGluZ3MtaHJkcmoLEgZYTUxEb2MiXlhCUkxEb2NHZW5JbmZvOmNkN2QzMThhNmU4MDRiZTQ5M2FmNjkwN2RhZTlhNjAxfFRleHRTZWxlY3Rpb246QTdFNDcyRkEzMkE5MUMwN0E2RjBFRURDRkEwM0QzNTgM}