Supplemental Guarantor Information Condensed Consolidated Balance Sheets (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents	$ 236,221	$ 162,182
Receivables	66,415	60,431
Ore on leach pads	78,801	64,167
Inventory, Net	72,329	106,026
Prepaid expenses and other	20,360	17,981
Current assets	474,126	410,787
Property, plant and equipment, net	235,058	216,796
Mining properties, net	536,201	558,455
Ore on leach pads	69,805	67,231
Restricted assets	20,953	17,597
Equity and debt securities	29,125	4,488
Receivables	13,461	30,951
Deferred Tax Assets, Net of Valuation Allowance, Noncurrent	0
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures	0	0
Other Assets, Noncurrent	23,363	12,604
TOTAL ASSETS	1,402,092	1,318,909
Accounts payable	60,188	53,335
Accrued liabilities and other	50,593	42,743
Debt	14,375	12,039
Royalty obligations	0	4,995
Reclamation	3,604	3,522
Liabilities, Current	128,760	116,634
Debt	274,523	198,857
Royalty obligations	0	4,292
Reclamation	104,505	95,804
Deferred tax liabilities	77,190	74,798
Other long-term liabilities	52,577	60,037
Intercompany Payable Receivable	0	0
Non-current liabilities	508,795	433,788
Common stock, par value $0.01 per share; authorized 300,000,000 shares, issued and outstanding 181,428,717 at September 30, 2017 and 180,933,287 at December 31, 2016	1,814	1,809
Additional paid-in capital	3,318,987	3,314,590
Accumulated deficit	(2,554,368)	(2,545,424)
Accumulated other comprehensive income (loss)	(1,896)	(2,488)
Stockholders' equity	764,537	768,487
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	1,402,092	1,318,909
Parent Company [Member]
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents	95,937	58,048
Receivables	18	12
Ore on leach pads	0	0
Inventory, Net	0	0
Prepaid expenses and other	7,688	3,803
Current assets	103,643	61,863
Property, plant and equipment, net	3,940	3,222
Mining properties, net	0	0
Ore on leach pads	0	0
Restricted assets	13,242	10,170
Equity and debt securities	27,558	0
Receivables	0	0
Deferred Tax Assets, Net of Valuation Allowance, Noncurrent	0
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures	259,259	273,056
Other Assets, Noncurrent	214,047	221,381
TOTAL ASSETS	621,689	569,692
Accounts payable	2,492	2,153
Accrued liabilities and other	9,381	12,881
Debt	0	0
Royalty obligations		0
Reclamation	0	0
Liabilities, Current	11,873	15,034
Debt	244,920	175,991
Royalty obligations		0
Reclamation	0	0
Deferred tax liabilities	14,978	13,810
Other long-term liabilities	2,328	1,993
Intercompany Payable Receivable	(416,947)	(405,623)
Non-current liabilities	(154,721)	(213,829)
Common stock, par value $0.01 per share; authorized 300,000,000 shares, issued and outstanding 181,428,717 at September 30, 2017 and 180,933,287 at December 31, 2016	1,814	1,809
Additional paid-in capital	3,318,987	3,314,590
Accumulated deficit	(2,554,368)	(2,545,424)
Accumulated other comprehensive income (loss)	(1,896)	(2,488)
Stockholders' equity	764,537	768,487
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	621,689	569,692
Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents	45,664	50,023
Receivables	11,085	6,865
Ore on leach pads	78,801	64,167
Inventory, Net	35,371	49,393
Prepaid expenses and other	2,985	1,459
Current assets	173,906	171,907
Property, plant and equipment, net	151,765	139,885
Mining properties, net	220,022	195,791
Ore on leach pads	69,805	67,231
Restricted assets	227	226
Equity and debt securities	1,567	4,488
Receivables	0	0
Deferred Tax Assets, Net of Valuation Allowance, Noncurrent	0
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures	407	11,650
Other Assets, Noncurrent	10,531	9,263
TOTAL ASSETS	628,230	600,441
Accounts payable	25,975	24,921
Accrued liabilities and other	14,087	13,664
Debt	7,885	6,516
Royalty obligations		4,995
Reclamation	2,754	2,672
Liabilities, Current	50,701	52,768
Debt	22,838	15,214
Royalty obligations		4,292
Reclamation	82,043	75,183
Deferred tax liabilities	6,137	6,179
Other long-term liabilities	4,061	4,750
Intercompany Payable Receivable	341,431	336,813
Non-current liabilities	456,510	442,431
Common stock, par value $0.01 per share; authorized 300,000,000 shares, issued and outstanding 181,428,717 at September 30, 2017 and 180,933,287 at December 31, 2016	250	250
Additional paid-in capital	174,111	181,009
Accumulated deficit	(49,984)	(73,529)
Accumulated other comprehensive income (loss)	(3,358)	(2,488)
Stockholders' equity	121,019	105,242
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	628,230	600,441
Non-Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Cash and cash equivalents	94,620	54,111
Receivables	55,312	53,554
Ore on leach pads	0	0
Inventory, Net	36,958	56,633
Prepaid expenses and other	9,687	12,719
Current assets	196,577	177,017
Property, plant and equipment, net	79,353	73,689
Mining properties, net	316,179	362,664
Ore on leach pads	0	0
Restricted assets	7,484	7,201
Equity and debt securities	0	0
Receivables	13,461	30,951
Deferred Tax Assets, Net of Valuation Allowance, Noncurrent	0
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures	(1,166)	0
Other Assets, Noncurrent	5,168	3,344
TOTAL ASSETS	617,056	654,866
Accounts payable	31,721	26,261
Accrued liabilities and other	27,125	16,198
Debt	6,490	5,523
Royalty obligations		0
Reclamation	850	850
Liabilities, Current	66,186	48,832
Debt	213,148	229,036
Royalty obligations		0
Reclamation	22,462	20,621
Deferred tax liabilities	56,075	54,809
Other long-term liabilities	46,188	53,294
Intercompany Payable Receivable	75,516	68,810
Non-current liabilities	413,389	426,570
Common stock, par value $0.01 per share; authorized 300,000,000 shares, issued and outstanding 181,428,717 at September 30, 2017 and 180,933,287 at December 31, 2016	172,599	197,913
Additional paid-in capital	1,803,807	1,864,261
Accumulated deficit	(1,838,925)	(1,882,710)
Accumulated other comprehensive income (loss)	0	0
Stockholders' equity	137,481	179,464
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	617,056	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 and debt securities	0	0
Receivables	0	0
Deferred Tax Assets, Net of Valuation Allowance, Noncurrent	0
Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures	(258,500)	(284,706)
Other Assets, Noncurrent	(206,383)	(221,384)
TOTAL ASSETS	(464,883)	(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	(206,383)	(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	(206,383)	(221,384)
Common stock, par value $0.01 per share; authorized 300,000,000 shares, issued and outstanding 181,428,717 at September 30, 2017 and 180,933,287 at December 31, 2016	(172,849)	(198,163)
Additional paid-in capital	(1,977,918)	(2,045,270)
Accumulated deficit	1,888,909	1,956,239
Accumulated other comprehensive income (loss)	3,358	2,488
Stockholders' equity	(258,500)	(284,706)
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	$ (464,883)	$ (506,090)