Segment Reporting (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012		Mar. 31, 2011		Dec. 31, 2011
Financial information relating to reporting segments
Sales of metal	$ 204,564		$ 199,624
Production costs applicable to sales	(92,554)		(92,474)
Depreciation and depletion	(52,592)		(50,041)
Gross profit (loss)	59,418		57,109
Exploration expense	6,567		2,762
OPERATING INCOME	44,187		38,542
Interest and other income	5,007		1,934
Interest expense	(6,670)		(9,304)
Loss on Debt Extinguishments	0		(467)
Fair value adjustments, net	(23,113)		(5,302)
Income tax benefit (expense)	(15,436)		(12,939)
Net income	3,975		12,464
Segment assets	3,226,493				3,264,441
Capital expenditures	31,647		15,918
Palmarejo [Member]
Financial information relating to reporting segments
Sales of metal	123,722		88,165
Production costs applicable to sales	(45,860)		(37,369)
Depreciation and depletion	(37,769)		(33,675)
Gross profit (loss)	40,093		17,121
Exploration expense	1,320		636
Other operating expenses	0		0
OPERATING INCOME	38,773		16,485
Interest and other income	4,581		1,289
Interest expense	(4,810)		(5,703)
Loss on Debt Extinguishments			0
Fair value adjustments, net	(25,611)		(6,343)
Income tax benefit (expense)	(3,544)		(3,776)
Net income	9,389		1,952
Segment assets	2,008,004	[1]	2,106,197	[1]
Capital expenditures	7,170	[2]	5,081	[2]
San Bartolome [Member]
Financial information relating to reporting segments
Sales of metal	41,376		46,321
Production costs applicable to sales	(13,608)		(14,118)
Depreciation and depletion	(4,219)		(5,143)
Gross profit (loss)	23,549		27,060
Exploration expense	70		4
Other operating expenses	5		38
OPERATING INCOME	23,474		27,018
Interest and other income	95		607
Interest expense	0		(34)
Loss on Debt Extinguishments			0
Fair value adjustments, net	0		0
Income tax benefit (expense)	(7,689)		(10,037)
Net income	15,880		17,554
Segment assets	285,276	[1]	269,158	[1]
Capital expenditures	10,207	[2]	3,536	[2]
Kensington [Member]
Financial information relating to reporting segments
Sales of metal	10,377		48,110
Production costs applicable to sales	(17,090)		(32,920)
Depreciation and depletion	(6,605)		(9,365)
Gross profit (loss)	(13,318)		5,825
Exploration expense	222		46
Other operating expenses	19		20
OPERATING INCOME	(13,559)		5,759
Interest and other income	0		1
Interest expense	(892)		(1,247)
Loss on Debt Extinguishments			0
Fair value adjustments, net	(551)		(698)
Income tax benefit (expense)	0		(20)
Net income	(15,002)		3,795
Segment assets	504,082	[1]	503,321	[1]
Capital expenditures	10,878	[2]	5,369	[2]
Rochester [Member]
Financial information relating to reporting segments
Sales of metal	18,758		14,262
Production costs applicable to sales	(9,565)		(7,357)
Depreciation and depletion	(1,642)		(514)
Gross profit (loss)	7,551		6,391
Exploration expense	709		21
Other operating expenses	1,341		3,536
OPERATING INCOME	5,501		2,834
Interest and other income	49		46
Interest expense	(8)		0
Loss on Debt Extinguishments			0
Fair value adjustments, net	0		0
Income tax benefit (expense)	0		0
Net income	5,542		2,880
Segment assets	90,072	[1]	27,049	[1]
Capital expenditures	2,639	[2]	1,668	[2]
Martha [Member]
Financial information relating to reporting segments
Sales of metal	3,618		(314)
Production costs applicable to sales	(3,694)		390
Depreciation and depletion	(596)		(592)
Gross profit (loss)	(672)		(516)
Exploration expense	3,412		1,296
Other operating expenses	197		0
OPERATING INCOME	(4,281)		(1,812)
Interest and other income	(75)		(311)
Interest expense	0		(345)
Loss on Debt Extinguishments			0
Fair value adjustments, net	0		0
Income tax benefit (expense)	(201)		41
Net income	(4,557)		(2,427)
Segment assets	24,183	[1]	17,571	[1]
Capital expenditures	659	[2]	251	[2]
Endeavor [Member]
Financial information relating to reporting segments
Sales of metal	6,713		3,080
Production costs applicable to sales	(2,737)		(1,100)
Depreciation and depletion	(1,644)		(619)
Gross profit (loss)	2,332		1,361
Exploration expense	0		0
Other operating expenses	0		0
OPERATING INCOME	2,332		1,361
Interest and other income	0		0
Interest expense	0		0
Loss on Debt Extinguishments			0
Fair value adjustments, net	0		0
Income tax benefit (expense)	0		0
Net income	2,332		1,361
Segment assets	36,372	[1]	39,093	[1]
Capital expenditures	0	[2]	0	[2]
Other Mining Properties [Member]
Financial information relating to reporting segments
Sales of metal	0		0
Production costs applicable to sales	0		0
Depreciation and depletion	(117)		(133)
Gross profit (loss)	(117)		(133)
Exploration expense	834		759
Other operating expenses	7,102		12,211
OPERATING INCOME	(8,053)		(13,103)
Interest and other income	357		302
Interest expense	(960)		(1,975)
Loss on Debt Extinguishments			(467)
Fair value adjustments, net	3,049		1,739
Income tax benefit (expense)	(4,002)		853
Net income	(9,609)		(12,651)
Segment assets	17,104	[1]	23,506	[1]
Capital expenditures	94	[2]	13	[2]
Reportable Segment [Member]
Financial information relating to reporting segments
Sales of metal	204,564		199,624
Production costs applicable to sales	(92,554)		(92,474)
Depreciation and depletion	(52,592)		(50,041)
Gross profit (loss)	59,418		57,109
Exploration expense	6,567		2,762
Other operating expenses	8,664		15,805
OPERATING INCOME	44,187		38,542
Interest and other income	5,007		1,934
Interest expense	(6,670)		(9,304)
Loss on Debt Extinguishments			(467)
Fair value adjustments, net	(23,113)		(5,302)
Income tax benefit (expense)	(15,436)		(12,939)
Net income	3,975		12,464
Segment assets	2,965,093	[1]	2,985,895	[1]
Capital expenditures	$ 31,647	[2]	$ 15,918	[2]

[1] Segment assets consist of receivables, prepaids, inventories, property, plant and equipment, and mining properties

[2] Balance represents cash flow amounts