Segment Reporting (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Financial information relating to reporting segments
Revenue		$ 148,795	$ 159,920	$ 482,049	$ 495,014
Costs applicable to sales	[1]	116,857	101,559	324,443	318,278
Amortization		31,184	32,400	91,420	101,827
Exploration		8,157	9,791	21,269	22,856
Loss on debt extinguishments		0	0	0	(9,342)
Other operating expenses		15,850	12,375	40,149	37,447
Fair value adjustments, net, pretax		715	0	2,907	(864)
Interest expense, net of capitalized interest		(5,818)	(3,595)	(17,801)	(10,918)
Other, net		(20,903)	2,361	(19,846)	27,134
Income and mining tax (expense) benefit		(3,785)	(14,289)	(19,451)	(24,040)
Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent		(53,044)	(11,728)	(49,423)	(3,424)
Income (loss) from discontinued operations		0	(4,924)	550	(5,520)
Assets, Net	[2]	1,429,100	1,027,967	1,429,100	1,027,967	$ 1,344,553
Capital expenditures		39,472	28,982	122,982	89,680
Palmarejo [Member]
Financial information relating to reporting segments
Revenue		55,456	60,677	196,237	191,616
Costs applicable to sales	[1]	31,554	33,255	92,960	110,150
Amortization		14,794	16,414	45,752	50,995
Exploration		3,195	4,517	10,363	9,272
Loss on debt extinguishments					0
Other operating expenses		771	319	2,252	930
Fair value adjustments, net, pretax		0		0	0
Interest expense, net of capitalized interest		(842)	(112)	(1,108)	(339)
Other, net		(1,010)	(218)	(2,399)	(345)
Income and mining tax (expense) benefit		(6,461)	(7,898)	(22,550)	(22,313)
Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent		(3,171)	(2,056)	18,853	(2,728)
Income (loss) from discontinued operations		0	0	0	0
Assets, Net	[2]	368,257	388,044	368,257	388,044
Capital expenditures		4,686	5,540	23,458	22,972
Rochester [Member]
Financial information relating to reporting segments
Revenue		35,524	31,156	102,689	102,926
Costs applicable to sales	[1]	27,548	23,275	76,304	73,875
Amortization		5,294	4,591	14,918	15,345
Exploration		51	531	296	990
Loss on debt extinguishments					0
Other operating expenses		4,362	846	6,149	2,487
Fair value adjustments, net, pretax		0		0	(864)
Interest expense, net of capitalized interest		(115)	(136)	(338)	(386)
Other, net		278	(73)	704	2,239
Income and mining tax (expense) benefit		(83)	41	(917)	(413)
Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent		(1,651)	1,745	4,471	10,805
Income (loss) from discontinued operations		0	0	0	0
Assets, Net	[2]	252,291	253,477	252,291	253,477
Capital expenditures		3,582	9,737	6,884	34,121
Silvertip [Member]
Financial information relating to reporting segments
Revenue		4,051		4,051
Costs applicable to sales	[1]	11,535		11,535
Amortization		1,073		1,073
Exploration		2,333		2,439
Other operating expenses		148		173
Fair value adjustments, net, pretax		0		0
Interest expense, net of capitalized interest		166		(490)
Other, net		(447)		(25)
Income and mining tax (expense) benefit		4,320		6,098
Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent		(6,999)		(5,586)
Income (loss) from discontinued operations		0		0
Assets, Net	[2]	405,334		405,334
Capital expenditures		17,949		55,623
Kensington [Member]
Financial information relating to reporting segments
Revenue		29,771	36,603	101,806	110,134
Costs applicable to sales	[1]	28,241	27,658	91,098	84,089
Amortization		6,912	7,864	20,070	25,389
Exploration		1,640	2,966	4,625	5,785
Loss on debt extinguishments					0
Other operating expenses		333	356	981	1,051
Fair value adjustments, net, pretax		0		0	0
Interest expense, net of capitalized interest		(248)	(113)	(722)	(266)
Other, net		(34)	(28)	(104)	(893)
Income and mining tax (expense) benefit		0	0	0	0
Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent		(7,637)	(2,382)	(15,794)	(7,339)
Income (loss) from discontinued operations		0	0	0	0
Assets, Net	[2]	225,161	211,052	225,161	211,052
Capital expenditures		11,960	10,144	34,032	24,314
Wharf [Member]
Financial information relating to reporting segments
Revenue		23,993	31,334	77,266	88,598
Costs applicable to sales	[1]	17,979	17,330	52,546	49,418
Amortization		2,878	3,223	8,888	8,883
Exploration		63	207	73	210
Loss on debt extinguishments					0
Other operating expenses		699	648	2,052	1,899
Fair value adjustments, net, pretax		0		0	0
Interest expense, net of capitalized interest		(9)	(16)	(32)	(52)
Other, net		(422)	4	(379)	429
Income and mining tax (expense) benefit		(334)	(963)	(2,009)	(2,980)
Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent		1,609	8,951	11,287	25,585
Income (loss) from discontinued operations		0	0	0	0
Assets, Net	[2]	98,978	103,843	98,978	103,843
Capital expenditures		1,176	3,135	2,682	5,493
Other Mining Properties [Member]
Financial information relating to reporting segments
Revenue		0	150	0	1,740
Costs applicable to sales	[1]	0	41	0	746
Amortization		233	308	719	1,215
Exploration		875	1,570	3,473	6,599
Loss on debt extinguishments					(9,342)
Other operating expenses		9,537	10,206	28,542	31,080
Fair value adjustments, net, pretax		715		2,907	0
Interest expense, net of capitalized interest		(4,770)	(3,218)	(15,111)	(9,875)
Other, net		(19,268)	2,676	(17,643)	25,704
Income and mining tax (expense) benefit		(1,227)	(5,469)	(73)	1,666
Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent		(35,195)	(17,986)	(62,654)	(29,747)
Income (loss) from discontinued operations		0	(4,924)	550	(5,520)
Assets, Net	[2]	79,079	71,551	79,079	71,551
Capital expenditures		$ 119	$ 426	$ 303	$ 2,780

[1] Excludes amortization.

[2] Segment assets include receivables, prepaids, inventories, property, plant and equipment, and mineral interest