Segment Reporting (Details) (USD $) In Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010	Mar. 31, 2011	Dec. 31, 2010	Mar. 31, 2010	Dec. 31, 2009
Financial information relating to reporting segments
Sales of metal	$ 231,090	$ 101,018	$ 430,714	$ 189,307
Production costs applicable to sales	(77,102)	(58,590)	(169,576)	(110,393)
Depreciation, depletion and amortization	(57,641)	(29,983)	(107,682)	(57,702)
Gross profit (loss)	96,347	12,445	153,456	21,212
Exploration expense	4,077	3,161	6,839	5,681
Other operating expenses	12,931	7,424	28,736	14,526
OPERATING INCOME	79,339	1,860	117,881	1,005
Interest income and other	2,763	(3,821)	4,664	(2,088)
Interest expense	9,268	5,646	18,573	11,451
Loss on debt extinguishment	(389)	(4,050)	(856)	(11,908)
Fair value adjustments, net	(12,432)	(42,516)	(17,700)	(46,774)
Income tax benefit (provision)	(21,402)	9,372	(34,341)	16,370
Income (loss) from continuing operations	38,611	(44,801)	51,075	(54,846)
Loss from discontinued operations, net of income taxes		(2,966)		(5,778)
Loss on sale of discontinued assets		(2,977)		(2,977)
Net income (loss)	38,611	(50,744)	51,075	(63,601)
Segment assets	2,984,289	2,997,376	2,984,289	2,997,376		3,000,389
Capital expenditures	25,764	45,467	41,681	92,656
Consolidated Assets
Total assets for reportable segments	2,984,289	2,997,376	2,984,289	2,997,376		3,000,389
Cash and cash equivalents	106,830	41,187	106,830	41,187	64,427	66,118	55,962	22,782
Receivables, non-current portion	40,941		40,941			42,866
Restricted assets	29,711		29,711			29,028
Debt issuance costs, net	3,167		3,167			4,333
Other assets	24,924		24,924			14,793
Total consolidated assets	3,188,971		3,188,971			3,157,527
Palmarejo [Member]
Financial information relating to reporting segments
Sales of metal	123,727	44,834	211,892	90,448
Production costs applicable to sales	(37,770)	(32,100)	(75,139)	(60,767)
Depreciation, depletion and amortization	(41,753)	(20,291)	(75,428)	(41,084)
Gross profit (loss)	44,204	(7,557)	61,325	(11,403)
Exploration expense	1,276	1,307	1,912	1,787
Other operating expenses		38		351
OPERATING INCOME	42,928	(8,902)	59,413	(13,541)
Interest income and other	539	(1,903)	1,828	261
Interest expense	6,112	5,401	11,815	10,868
Fair value adjustments, net	(13,731)	(32,633)	(20,041)	(36,179)
Income tax benefit (provision)	(6,286)	(4,006)	(10,062)	2,857
Net income (loss)	17,338	(52,845)	19,323	(57,470)
Segment assets	2,095,411	2,140,633	2,095,411	2,140,633
Capital expenditures	10,278	(10,811)	15,359	(27,319)
Consolidated Assets
Total assets for reportable segments	2,095,411	2,140,633	2,095,411	2,140,633
Rochester [Member]
Financial information relating to reporting segments
Sales of metal	14,434	12,416	28,696	23,167
Production costs applicable to sales	(5,341)	(5,595)	(12,968)	(11,384)
Depreciation, depletion and amortization	(584)	(458)	(1,098)	(923)
Gross profit (loss)	8,509	6,363	14,900	10,860
Exploration expense	340	20	362	41
Other operating expenses	(11,025)	(601)	(14,561)	(773)
OPERATING INCOME	(2,856)	5,742	(23)	10,046
Interest income and other	5	1	51	1
Net income (loss)	(2,851)	5,743	28	10,047
Segment assets	35,606	28,625	35,606	28,625
Capital expenditures	4,201	(86)	5,869	(87)
Consolidated Assets
Total assets for reportable segments	35,606	28,625	35,606	28,625
San Bartolome [Member]
Financial information relating to reporting segments
Sales of metal	55,598	31,275	101,919	45,867
Production costs applicable to sales	(14,126)	(15,340)	(28,244)	(24,743)
Depreciation, depletion and amortization	(5,182)	(6,032)	(10,325)	(9,209)
Gross profit (loss)	36,290	9,903	63,350	11,915
Exploration expense	31		35
Other operating expenses	70		108
OPERATING INCOME	36,189	9,903	63,207	11,915
Interest income and other	180	(105)	787	(144)
Interest expense	(2)	(92)	(36)	(163)
Income tax benefit (provision)	12,109	3,909	22,146	4,501
Net income (loss)	24,258	5,797	41,812	7,107
Segment assets	269,439	274,156	269,439	274,156
Capital expenditures	3,276	(1,325)	6,812	(1,871)
Consolidated Assets
Total assets for reportable segments	269,439	274,156	269,439	274,156
Martha [Member]
Financial information relating to reporting segments
Sales of metal	4,769	9,187	4,455	24,207
Production costs applicable to sales	(3,749)	(4,132)	(3,359)	(11,458)
Depreciation, depletion and amortization	747	(2,619)	155	(5,104)
Gross profit (loss)	1,767	2,436	1,251	7,645
Exploration expense	1,527	1,205	2,823	2,415
OPERATING INCOME	240	1,231	(1,572)	5,230
Interest income and other	(179)	(2,180)	(489)	(2,950)
Interest expense	(68)	(17)	(413)	(55)
Income tax benefit (provision)	410	2,160	369	2,173
Net income (loss)	(417)	(3,126)	(2,843)	52
Segment assets	19,341	26,269	19,341	26,269
Capital expenditures	573	11	824	3
Consolidated Assets
Total assets for reportable segments	19,341	26,269	19,341	26,269
Endeavor [Member]
Financial information relating to reporting segments
Sales of metal	6,550	3,306	9,630	5,618
Production costs applicable to sales	(3,272)	1,423	(4,372)	2,041
Depreciation, depletion and amortization	(865)	450	(1,484)	1,110
Gross profit (loss)	2,413	1,433	3,774	2,467
OPERATING INCOME	2,413	1,433	3,774	2,467
Income tax benefit (provision)	3		(3)
Net income (loss)	2,410	1,433	3,771	2,467
Segment assets	40,760	39,210	40,760	39,210
Consolidated Assets
Total assets for reportable segments	40,760	39,210	40,760	39,210
Kensington [Member]
Financial information relating to reporting segments
Sales of metal	26,012		74,122
Production costs applicable to sales	(12,844)		(45,764)
Depreciation, depletion and amortization	(9,890)		(19,255)
Gross profit (loss)	3,278		9,103
Exploration expense	320	229	366	242
Other operating expenses	(116)		(136)
OPERATING INCOME	2,842	(229)	8,601	(242)
Interest income and other	2		3
Interest expense	1,360		2,607
Fair value adjustments, net	2,374	(6,089)	1,676	(6,552)
Income tax benefit (provision)			(20)
Net income (loss)	3,858	(6,318)	7,653	(6,794)
Segment assets	507,531	477,800	507,531	477,800
Capital expenditures	7,365	(33,196)	12,734	(63,097)
Consolidated Assets
Total assets for reportable segments	507,531	477,800	507,531	477,800
Other Mining Properties [Member]
Financial information relating to reporting segments
Depreciation, depletion and amortization	(114)	(133)	(247)	(272)
Gross profit (loss)	(114)	(133)	(247)	(272)
Exploration expense	583	400	1,341	1,196
Other operating expenses	1,720	6,785	13,931	13,402
OPERATING INCOME	(2,417)	(7,318)	(15,519)	(14,870)
Interest income and other	2,216	366	2,484	744
Interest expense	1,726	136	3,702	365
Loss on debt extinguishment	(389)	(4,050)	(856)	(11,908)
Fair value adjustments, net	(1,075)	(3,794)	665	(4,043)
Income tax benefit (provision)	(2,594)	19,447	(1,741)	20,187
Loss from discontinued operations, net of income taxes		(5,943)		(8,755)
Net income (loss)	(5,985)	(1,428)	(18,669)	(19,010)
Segment assets	16,201	10,683	16,201	10,683
Capital expenditures	71	(39)	83	(279)
Consolidated Assets
Total assets for reportable segments	$ 16,201	$ 10,683	$ 16,201	$ 10,683