Supplemental Guarantor Information Condensed Consolidated Balance Sheets (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents	$ 250,038	$ 162,182
Receivables	69,656	60,431
Ore on leach pads	75,699	64,167
Inventory, Net	67,895	106,026
Prepaid expenses and other	18,563	17,981
Current assets	481,851	410,787
Property, plant and equipment, net	227,738	216,796
Mining properties, net	550,247	558,455
Ore on leach pads	69,954	67,231
Restricted assets	19,294	17,597
Equity securities	11,872	4,488
Receivables	15,140	30,951
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures	0	0
Other Assets, Noncurrent	18,552	12,604
TOTAL ASSETS	1,394,648	1,318,909
Accounts payable	58,800	53,335
Accrued liabilities and other	41,250	42,743
Debt	13,014	12,039
Royalty obligations	0	4,995
Reclamation	3,599	3,522
Liabilities, Current	116,663	116,634
Debt	271,766	198,857
Royalty obligations	0	4,292
Reclamation	99,541	95,804
Deferred tax liabilities	75,388	74,798
Other long-term liabilities	53,779	60,037
Intercompany Payable Receivable	0	0
Non-current liabilities	500,474	433,788
Common stock, par value $0.01 per share; authorized 300,000,000 shares, issued and outstanding 181,441,769 at June 30, 2017 and 180,933,287 at December 31, 2016	1,814	1,809
Additional paid-in capital	3,316,407	3,314,590
Accumulated deficit	(2,537,716)	(2,545,424)
Accumulated other comprehensive income (loss)	(2,994)	(2,488)
Stockholders' equity	777,511	768,487
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	1,394,648	1,318,909
Parent Company [Member]
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents	103,878	58,048
Receivables	54	12
Ore on leach pads	0	0
Inventory, Net	0	0
Prepaid expenses and other	6,696	3,803
Current assets	110,628	61,863
Property, plant and equipment, net	3,908	3,222
Mining properties, net	4,000	0
Ore on leach pads	0	0
Restricted assets	11,711	10,170
Equity securities	9,930	0
Receivables	0	0
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures	274,908	273,056
Other Assets, Noncurrent	211,384	221,381
TOTAL ASSETS	626,469	569,692
Accounts payable	1,599	2,153
Accrued liabilities and other	5,638	12,881
Debt	0	0
Royalty obligations		0
Reclamation	0	0
Liabilities, Current	7,237	15,034
Debt	244,827	175,991
Royalty obligations		0
Reclamation	0	0
Deferred tax liabilities	5,304	13,810
Other long-term liabilities	2,390	1,993
Intercompany Payable Receivable	(410,800)	(405,623)
Non-current liabilities	(158,279)	(213,829)
Common stock, par value $0.01 per share; authorized 300,000,000 shares, issued and outstanding 181,441,769 at June 30, 2017 and 180,933,287 at December 31, 2016	1,814	1,809
Additional paid-in capital	3,316,407	3,314,590
Accumulated deficit	(2,537,716)	(2,545,424)
Accumulated other comprehensive income (loss)	(2,994)	(2,488)
Stockholders' equity	777,511	768,487
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	626,469	569,692
Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents	47,912	50,023
Receivables	13,527	6,865
Ore on leach pads	75,699	64,167
Inventory, Net	35,099	49,393
Prepaid expenses and other	2,366	1,459
Current assets	174,603	171,907
Property, plant and equipment, net	146,826	139,885
Mining properties, net	210,785	195,791
Ore on leach pads	69,954	67,231
Restricted assets	226	226
Equity securities	1,942	4,488
Receivables	0	0
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures	12,858	11,650
Other Assets, Noncurrent	10,186	9,263
TOTAL ASSETS	627,380	600,441
Accounts payable	24,168	24,921
Accrued liabilities and other	12,299	13,664
Debt	7,338	6,516
Royalty obligations		4,995
Reclamation	2,749	2,672
Liabilities, Current	46,554	52,768
Debt	22,163	15,214
Royalty obligations		4,292
Reclamation	77,743	75,183
Deferred tax liabilities	6,137	6,179
Other long-term liabilities	4,758	4,750
Intercompany Payable Receivable	336,771	336,813
Non-current liabilities	447,572	442,431
Common stock, par value $0.01 per share; authorized 300,000,000 shares, issued and outstanding 181,441,769 at June 30, 2017 and 180,933,287 at December 31, 2016	250	250
Additional paid-in capital	182,611	181,009
Accumulated deficit	(46,225)	(73,529)
Accumulated other comprehensive income (loss)	(3,382)	(2,488)
Stockholders' equity	133,254	105,242
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	627,380	600,441
Non-Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents	98,248	54,111
Receivables	56,075	53,554
Ore on leach pads	0	0
Inventory, Net	32,796	56,633
Prepaid expenses and other	9,501	12,719
Current assets	196,620	177,017
Property, plant and equipment, net	77,004	73,689
Mining properties, net	335,462	362,664
Ore on leach pads	0	0
Restricted assets	7,357	7,201
Equity securities	0	0
Receivables	15,140	30,951
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures	(861)	0
Other Assets, Noncurrent	8,366	3,344
TOTAL ASSETS	639,088	654,866
Accounts payable	33,033	26,261
Accrued liabilities and other	23,313	16,198
Debt	5,676	5,523
Royalty obligations		0
Reclamation	850	850
Liabilities, Current	62,872	48,832
Debt	216,160	229,036
Royalty obligations		0
Reclamation	21,798	20,621
Deferred tax liabilities	63,947	54,809
Other long-term liabilities	46,631	53,294
Intercompany Payable Receivable	74,029	68,810
Non-current liabilities	422,565	426,570
Common stock, par value $0.01 per share; authorized 300,000,000 shares, issued and outstanding 181,441,769 at June 30, 2017 and 180,933,287 at December 31, 2016	193,175	197,913
Additional paid-in capital	1,809,559	1,864,261
Accumulated deficit	(1,849,083)	(1,882,710)
Accumulated other comprehensive income (loss)	0	0
Stockholders' equity	153,651	179,464
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	639,088	654,866
Eliminations
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents	0	0
Receivables	0	0
Ore on leach pads	0	0
Inventory, Net	0	0
Prepaid expenses and other	0	0
Current assets	0	0
Property, plant and equipment, net	0	0
Mining properties, net	0	0
Ore on leach pads	0	0
Restricted assets	0	0
Equity securities	0	0
Receivables	0	0
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures	(286,905)	(284,706)
Other Assets, Noncurrent	(211,384)	(221,384)
TOTAL ASSETS	(498,289)	(506,090)
Accounts payable	0	0
Accrued liabilities and other	0	0
Debt	0	0
Royalty obligations		0
Reclamation	0	0
Liabilities, Current	0	0
Debt	(211,384)	(221,384)
Royalty obligations		0
Reclamation	0	0
Deferred tax liabilities	0	0
Other long-term liabilities	0	0
Intercompany Payable Receivable	0	0
Non-current liabilities	(211,384)	(221,384)
Common stock, par value $0.01 per share; authorized 300,000,000 shares, issued and outstanding 181,441,769 at June 30, 2017 and 180,933,287 at December 31, 2016	(193,425)	(198,163)
Additional paid-in capital	(1,992,170)	(2,045,270)
Accumulated deficit	1,895,308	1,956,239
Accumulated other comprehensive income (loss)	3,382	2,488
Stockholders' equity	(286,905)	(284,706)
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	$ (498,289)	$ (506,090)