Segment Reporting (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013		Mar. 31, 2012		Dec. 31, 2012
Financial information relating to reporting segments
Sales of metal	$ 171,797		$ 204,564
Production costs applicable to sales	(88,784)		(92,554)
Depreciation and depletion	(50,436)		(52,592)
Gross profit	32,577		59,418
Exploration expense	6,841		6,567
Loss on impairment	119		0
OPERATING INCOME	10,905		44,187
Interest and other income	3,821		5,007
Interest expense	(9,732)		(6,670)
Fair value adjustments, net	17,796		(23,113)
Income tax benefit (expense)	(10,520)		(15,436)
Net income	12,270		3,975
Capital expenditures	12,827		31,647
Assets	3,423,682				3,221,401
Palmarejo [Member]
Financial information relating to reporting segments
Sales of metal	57,426		123,722
Production costs applicable to sales	(26,718)		(45,860)
Depreciation and depletion	(28,950)		(37,769)
Gross profit	1,758		40,093
Exploration expense	1,980		1,320
Other operating expenses	0		0
OPERATING INCOME	(222)		38,773
Interest and other income	1,941		4,581
Interest expense	(3,738)		(4,810)
Fair value adjustments, net	14,429		(25,611)
Income tax benefit (expense)	(3,534)		(3,544)
Net income	8,876		9,389
Capital expenditures	5,314	[1]	7,170	[1]
Assets	1,900,071	[2]	2,008,004	[2]
San Bartolome [Member]
Financial information relating to reporting segments
Sales of metal	33,141		41,376
Production costs applicable to sales	(15,678)		(13,608)
Depreciation and depletion	(4,756)		(4,219)
Gross profit	12,707		23,549
Exploration expense	53		70
Other operating expenses	3,721		5
OPERATING INCOME	8,933		23,474
Interest and other income	605		95
Interest expense	(32)		0
Fair value adjustments, net	0		0
Income tax benefit (expense)	(4,328)		(7,689)
Net income	5,178		15,880
Capital expenditures	457	[1]	10,207	[1]
Assets	303,761	[2]	285,276	[2]
Kensington [Member]
Financial information relating to reporting segments
Sales of metal	39,274		10,377
Production costs applicable to sales	(23,565)		(17,090)
Depreciation and depletion	(13,386)		(6,605)
Gross profit	2,323		(13,318)
Exploration expense	672		222
Other operating expenses	76		19
OPERATING INCOME	1,575		(13,559)
Interest and other income	130		0
Interest expense	(259)		(892)
Fair value adjustments, net	4,227		(551)
Income tax benefit (expense)	0		0
Net income	5,673		(15,002)
Capital expenditures	3,330	[1]	10,878	[1]
Assets	498,762	[2]	504,082	[2]
Rochester [Member]
Financial information relating to reporting segments
Sales of metal	39,474		18,758
Production costs applicable to sales	(21,502)		(9,565)
Depreciation and depletion	(2,181)		(1,642)
Gross profit	15,791		7,551
Exploration expense	484		709
Other operating expenses	144		1,341
OPERATING INCOME	15,163		5,501
Interest and other income	57		49
Interest expense	(5)		(8)
Fair value adjustments, net	0		0
Income tax benefit (expense)	0		0
Net income	15,215		5,542
Capital expenditures	3,299	[1]	2,639	[1]
Assets	114,381	[2]	90,072	[2]
Martha [Member]
Financial information relating to reporting segments
Sales of metal	(501)		3,618
Production costs applicable to sales	0		(3,694)
Depreciation and depletion	(117)		(596)
Gross profit	(618)		(672)
Exploration expense	2,995		3,412
Loss on impairment	119
Other operating expenses	1,045		197
OPERATING INCOME	(4,777)		(4,281)
Interest and other income	908		(75)
Interest expense	(15)		0
Fair value adjustments, net	0		0
Income tax benefit (expense)	73		(201)
Net income	(3,811)		(4,557)
Capital expenditures	0	[1]	659	[1]
Assets	8,304	[2]	24,183	[2]
Endeavor [Member]
Financial information relating to reporting segments
Sales of metal	2,983		6,713
Production costs applicable to sales	(1,321)		(2,737)
Depreciation and depletion	(824)		(1,644)
Gross profit	838		2,332
Exploration expense	0		0
Other operating expenses	0		0
OPERATING INCOME	838		2,332
Interest and other income	(13)		0
Interest expense	0		0
Fair value adjustments, net	0		0
Income tax benefit (expense)	0		0
Net income	825		2,332
Capital expenditures	0	[1]	0	[1]
Assets	93,770	[2]	36,372	[2]
Joaquin [Member]
Financial information relating to reporting segments
Sales of metal	0		0
Production costs applicable to sales	0		0
Depreciation and depletion	0		0
Gross profit	0		0
Exploration expense	0		0
Other operating expenses	11		0
OPERATING INCOME	(11)		0
Interest and other income	(14)		0
Interest expense	15		0
Fair value adjustments, net	0		0
Income tax benefit (expense)	0		0
Net income	(10)		0
Capital expenditures	0	[1]	0	[1]
Assets	31,054	[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	(222)		(117)
Gross profit	(222)		(117)
Exploration expense	657		834
Other operating expenses	9,714		7,102
OPERATING INCOME	(10,593)		(8,053)
Interest and other income	206		357
Interest expense	(5,698)		(960)
Fair value adjustments, net	(860)		3,049
Income tax benefit (expense)	(2,731)		(4,002)
Net income	(19,676)		(9,609)
Capital expenditures	427	[1]	94	[1]
Assets	13,561	[2]	17,104	[2]
Reportable Segment [Member]
Financial information relating to reporting segments
Sales of metal	171,797		204,564
Production costs applicable to sales	(88,784)		(92,554)
Depreciation and depletion	(50,436)		(52,592)
Gross profit	32,577		59,418
Exploration expense	6,841		6,567
Loss on impairment	119
Other operating expenses	14,711		8,664
OPERATING INCOME	10,906		44,187
Interest and other income	3,820		5,007
Interest expense	(9,732)		(6,670)
Fair value adjustments, net	17,796		(23,113)
Income tax benefit (expense)	(10,520)		(15,436)
Net income	12,270		3,975
Capital expenditures	12,827	[1]	31,647	[1]
Assets	$ 2,963,664	[2]	$ 2,965,093	[2]

[1] Balance represents cash flow amounts

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