Segment Reporting (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2013		Sep. 30, 2012		Sep. 30, 2013		Sep. 30, 2012		Dec. 31, 2012
Financial information relating to reporting segments
Sales of metal	$ 200,825		$ 230,593		$ 577,147		$ 689,563
Production costs applicable to sales	(131,728)		(124,967)		(363,437)		(349,344)
Depreciation, Depletion and Amortization	(60,874)		(52,844)		(168,963)		(166,460)
Gross profit	8,223		52,782		44,747		173,759
Exploration	3,305		6,957		16,920		19,829
Loss on impairment	0		1,293		205		6,106
Other operating expenses			0		1,888		0
OPERATING INCOME (LOSS)	(15,277)		33,989		(55,330)		119,750
Interest and Other Income	(1,791)		13,269		2,484		15,055
Interest Expense	(9,662)		(7,351)		(30,324)		(21,578)
Fair value adjustments, net	(20,646)		(37,648)		63,905		(44,722)
Income tax provision	1,981		(17,475)		(31,673)		(56,773)
NET INCOME (LOSS)	(46,265)		(15,821)		(69,035)		11,127
Capital expenditures	32,726		29,972		72,754		93,857
Assets	3,636,917				3,636,917				3,221,401
Palmarejo [Member]
Financial information relating to reporting segments
Sales of metal	104,524		102,642		248,167		362,729
Production costs applicable to sales	(66,839)		(48,672)		(148,776)		(157,070)
Depreciation, Depletion and Amortization	(33,654)		(34,007)		(98,161)		(114,525)
Gross profit	4,031		19,963		1,230		91,134
Exploration	860		2,288		6,029		5,232
Loss on impairment			0		0		0
Other operating expenses	0		0		0		0
OPERATING INCOME (LOSS)	3,171		17,675		(4,799)		85,902
Interest and Other Income	(2,281)		4,914		(768)		4,774
Interest Expense	(2,925)		(4,401)		(10,853)		(14,883)
Fair value adjustments, net	(15,260)		(34,266)		60,234		(45,771)
Income tax provision	1,564		5,495		(17,383)		(10,015)
NET INCOME (LOSS)	(15,731)		(10,583)		26,431		20,007
Capital expenditures	10,290	[1]	11,321	[1]	24,770	[1]	29,665	[1]
Assets	1,825,599	[2]	1,926,695	[2]	1,825,599	[2]	1,926,695	[2]
San Bartolome [Member]
Financial information relating to reporting segments
Sales of metal	28,819		46,192		111,196		140,951
Production costs applicable to sales	(17,673)		(19,937)		(66,165)		(56,317)
Depreciation, Depletion and Amortization	(4,909)		(4,163)		(14,606)		(12,452)
Gross profit	6,237		22,092		30,425		72,182
Exploration	(3)		50		76		51
Loss on impairment			0		0		0
Other operating expenses	1,969		50		5,691		80
OPERATING INCOME (LOSS)	4,271		21,992		24,658		72,051
Interest and Other Income	582		8,353		1,871		9,079
Interest Expense	(12)		(11)		(59)		(47)
Fair value adjustments, net	0		0		0		0
Income tax provision	(4,648)		(23,106)		(13,482)		(41,684)
NET INCOME (LOSS)	193		7,228		12,988		39,399
Capital expenditures	4,166	[1]	4,406	[1]	7,782	[1]	22,413	[1]
Assets	289,274	[2]	299,041	[2]	289,274	[2]	299,041	[2]
Kensington [Member]
Financial information relating to reporting segments
Sales of metal	38,927		36,450		109,053		67,950
Production costs applicable to sales	(27,484)		(26,881)		(81,203)		(60,078)
Depreciation, Depletion and Amortization	(18,190)		(11,512)		(44,837)		(27,836)
Gross profit	(6,747)		(1,943)		(16,987)		(19,964)
Exploration	1,496		1,476		2,732		1,971
Loss on impairment			0		0		0
Other operating expenses	(6)		39		204		75
OPERATING INCOME (LOSS)	(8,237)		(3,458)		(19,923)		(22,010)
Interest and Other Income	0		0		281		1
Interest Expense	(51)		(1,834)		(405)		(3,627)
Fair value adjustments, net	(2,952)		(4,283)		7,626		(2,647)
Income tax provision	0		0		(1)		0
NET INCOME (LOSS)	(11,240)		(9,575)		(12,422)		(28,283)
Capital expenditures	4,934	[1]	9,034	[1]	15,670	[1]	29,235	[1]
Assets	481,613	[2]	520,619	[2]	481,613	[2]	520,619	[2]
Rochester [Member]
Financial information relating to reporting segments
Sales of metal	24,259		36,244		98,636		89,156
Production costs applicable to sales	(17,861)		(21,014)		(62,418)		(51,331)
Depreciation, Depletion and Amortization	(2,860)		(2,061)		(7,365)		(5,763)
Gross profit	3,538		13,169		28,853		32,062
Exploration	624		1,158		1,621		3,003
Loss on impairment			0		0		0
Other operating expenses	173		1,109		34,494		3,142
OPERATING INCOME (LOSS)	2,741		10,902		(7,262)		25,917
Interest and Other Income	60		59		117		347
Interest Expense	(5)		(6)		(16)		(21)
Fair value adjustments, net	(2,363)		0		(2,363)		0
Income tax provision	0		0		0		0
NET INCOME (LOSS)	433		10,955		(9,524)		26,243
Capital expenditures	12,267	[1]	4,777	[1]	22,161	[1]	10,362	[1]
Assets	161,993	[2]	104,066	[2]	161,993	[2]	104,066	[2]
Martha [Member]
Financial information relating to reporting segments
Sales of metal	0		4,933		(662)		12,700
Production costs applicable to sales	0		(6,481)		0		(17,276)
Depreciation, Depletion and Amortization	(108)		(32)		(338)		(1,332)
Gross profit	(108)		(1,580)		(1,000)		(5,908)
Exploration	282		1,217		4,460		7,391
Loss on impairment			1,293		205		6,106
Other operating expenses	738		133		2,643		411
OPERATING INCOME (LOSS)	(1,128)		(4,223)		(8,308)		(19,816)
Interest and Other Income	(595)		(342)		166		(912)
Interest Expense	0		(2)		0		(3)
Fair value adjustments, net	0		0		0		0
Income tax provision	5		1,233		(38)		993
NET INCOME (LOSS)	(1,718)		(3,334)		(8,180)		(19,738)
Capital expenditures	0	[1]	6	[1]	10	[1]	1,194	[1]
Assets	6,146	[2]	11,339	[2]	6,146	[2]	11,339	[2]
Endeavor [Member]
Financial information relating to reporting segments
Sales of metal	4,296		4,132		10,757		16,077
Production costs applicable to sales	(1,871)		(1,982)		(4,874)		(7,272)
Depreciation, Depletion and Amortization	(894)		(898)		(2,938)		(4,134)
Gross profit	1,531		1,252		2,945		4,671
Exploration	0		0		0		0
Loss on impairment			0		0		0
Other operating expenses	0		0		0		0
OPERATING INCOME (LOSS)	1,531		1,252		2,945		4,671
Interest and Other Income	0		0		0		0
Interest Expense	0		0		0		0
Fair value adjustments, net	0		0		0		0
Income tax provision	0		(202)		0		(202)
NET INCOME (LOSS)	1,531		1,050		2,945		4,469
Capital expenditures	0	[1]	0	[1]	0	[1]	0	[1]
Assets	27,938	[2]	32,619	[2]	27,938	[2]	32,619	[2]
Joaquin [Member]
Financial information relating to reporting segments
Sales of metal	0		0		0
Production costs applicable to sales	0		0		0		0
Depreciation, Depletion and Amortization	(11)		0		(12)		0
Gross profit	(11)		0		(12)		0
Exploration	(671)		0		19		0
Loss on impairment			0		0		0
Other operating expenses	1,888
OPERATING INCOME (LOSS)	(1,228)		0		(1,919)		0
Interest and Other Income	19		0		8		0
Interest Expense	0		0		0		0
Fair value adjustments, net	0		0		0		0
Income tax provision	0		0		0		0
NET INCOME (LOSS)	(1,209)		0		(1,911)		0
Capital expenditures	358	[1]	0	[1]	1,093	[1]	0	[1]
Assets	410,085	[2]	0	[2]	410,085	[2]	0	[2]
Other Mining Properties [Member]
Financial information relating to reporting segments
Sales of metal	0		0		0		0
Production costs applicable to sales	0		0		(1)		0
Depreciation, Depletion and Amortization	(248)		(171)		(706)		(418)
Gross profit	(248)		(171)		(707)		(418)
Exploration	717		768		1,983		2,181
Loss on impairment			0		0		0
Other operating expenses	15,433		9,212		38,032		24,366
OPERATING INCOME (LOSS)	(16,398)		(10,151)		(40,722)		(26,965)
Interest and Other Income	(446)		(320)		(17,288)		1,161
Interest Expense	(6,669)		(1,097)		(18,991)		(2,997)
Fair value adjustments, net	(71)		901		(1,592)		3,696
Income tax provision	5,060		(895)		(769)		(5,865)
NET INCOME (LOSS)	(18,524)		(11,562)		(79,362)		(30,970)
Capital expenditures	711	[1]	428	[1]	1,268	[1]	988	[1]
Assets	109,520	[2]	18,613	[2]	109,520	[2]	18,613	[2]
Reportable Segment [Member]
Financial information relating to reporting segments
Sales of metal	200,825		230,593		577,147		689,563
Production costs applicable to sales	(131,728)		(124,967)		(363,437)		(349,344)
Depreciation, Depletion and Amortization	(60,874)		(52,844)		(168,963)		(166,460)
Gross profit	8,223		52,782		44,747		173,759
Exploration	3,305		6,957		16,920		19,829
Loss on impairment			1,293		205		6,106
Other operating expenses	20,195		10,543		82,952		28,074
OPERATING INCOME (LOSS)	(15,277)		33,989		(55,330)		119,750
Interest and Other Income	(2,661)		12,664		(15,613)		14,450
Interest Expense	(9,662)		(7,351)		(30,324)		(21,578)
Fair value adjustments, net	(20,646)		(37,648)		63,905		(44,722)
Income tax provision	1,981		(17,475)		(31,673)		(56,773)
NET INCOME (LOSS)	(46,265)		(15,821)		(69,035)		11,127
Capital expenditures	32,726	[1]	29,972	[1]	72,754	[1]	93,857	[1]
Assets	$ 3,312,168	[2]	$ 2,912,992	[2]	$ 3,312,168	[2]	$ 2,912,992	[2]

[1] Three months ended September 30, 2012PalmarejoMine San BartoloméMine KensingtonMine RochesterMine MarthaMine EndeavorMine La Preciosa Other TotalSales of metals$102,642 $46,192 $36,450 $36,244 $4,933 $4,132 $— $— $230,593Production costs applicable to sales(48,672) (19,937) (26,881) (21,014) (6,481) (1,982) — — (124,967)Depreciation and depletion(34,007) (4,163) (11,512) (2,061) (32) (898) — (171) (52,844)Gross profit19,963 22,092 (1,943) 13,169 (1,580) 1,252 — (171) 52,782Exploration expense2,288 50 1,476 1,158 1,217 — — 768 6,957Loss on impairment— — — — 1,293 — — — 1,293Other operating expenses— 50 39 1,109 133 — — 9,212 10,543OPERATING INCOME / LOSS17,675 21,992 (3,458) 10,902 (4,223) 1,252 — (10,151) 33,989Interest and other income, net4,914 8,353 — 59 (342) — — (320) 12,664Interest expense(4,401) (11) (1,834) (6) (2) — — (1,097) (7,351)Fair value adjustments, net(34,266) — (4,283) — — — — 901 (37,648)Income tax benefit (expense)5,495 (23,106) — — 1,233 (202) — (895) (17,475)Net income (loss)$(10,583) $7,228 $(9,575) $10,955 $(3,334) $1,050 $— $(11,562) $(15,821)Segment assets (A)$1,926,695 $299,041 $520,619 $104,066 $11,339 $32,619 $— $18,613 $2,912,992Capital expenditures (B)$11,321 $4,406 $9,034 $4,777 $6 $— $— $428 $29,972

[2]