Segment Reporting (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Financial information relating to reporting segments
Revenue		$ 169,987	$ 149,540	$ 333,254	$ 335,094
Costs applicable to sales	[1]	108,246	102,229	207,586	216,719
Amortization		29,459	30,734	60,236	69,427
Exploration		6,429	7,813	13,112	13,065
Loss on debt extinguishments		0	(9,342)	0	(9,342)
Other operating expenses		11,270	11,110	24,299	25,072
Fair value adjustments, net, pretax		(2,462)	336	2,192	(864)
Interest expense, net of capitalized interest		(6,018)	(3,744)	(11,983)	(7,323)
Other, net		544	3,974	1,057	24,773
Income and mining tax (expense) benefit		(3,717)	1,127	(15,666)	(9,751)
Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent		2,930	(9,995)	3,621	8,304
Income (loss) from discontinued operations		0	(960)	550	(596)
Assets, Net	[2]	1,447,904	1,033,387	1,447,904	1,033,387	$ 1,344,553
Capital expenditures		41,165	37,107	83,510	60,698
Palmarejo [Member]
Financial information relating to reporting segments
Revenue		70,744	53,235	140,781	130,939
Costs applicable to sales	[1]	30,310	33,894	61,406	76,895
Amortization		14,633	14,431	30,958	34,581
Exploration		3,198	3,124	7,168	4,755
Loss on debt extinguishments			0		0
Other operating expenses		750	310	1,481	611
Fair value adjustments, net, pretax		0	0	0	0
Interest expense, net of capitalized interest		(147)	(102)	(266)	(227)
Other, net		755	(498)	(1,389)	(127)
Income and mining tax (expense) benefit		(3,646)	(3,229)	(16,089)	(14,415)
Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent		18,815	(2,353)	22,024	(672)
Income (loss) from discontinued operations		0	0	0	0
Assets, Net	[2]	373,310	397,254	373,310	397,254
Capital expenditures		9,479	11,202	18,772	17,432
Rochester [Member]
Financial information relating to reporting segments
Revenue		33,668	32,791	67,165	71,770
Costs applicable to sales	[1]	24,451	24,161	48,756	50,600
Amortization		4,793	4,938	9,624	10,754
Exploration		212	315	245	459
Loss on debt extinguishments			0		0
Other operating expenses		903	831	1,787	1,641
Fair value adjustments, net, pretax		0	336	0	(864)
Interest expense, net of capitalized interest		(125)	(133)	(223)	(250)
Other, net		466	2,344	426	2,312
Income and mining tax (expense) benefit		(463)	44	(834)	(454)
Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent		3,187	5,137	6,122	9,060
Income (loss) from discontinued operations		0	0	0	0
Assets, Net	[2]	253,638	241,381	253,638	241,381
Capital expenditures		669	13,816	3,302	24,384
Silvertip [Member]
Financial information relating to reporting segments
Revenue		0		0
Costs applicable to sales	[1]	0		0
Amortization		0		0
Exploration		106		106
Other operating expenses		5		25
Fair value adjustments, net, pretax		0		0
Interest expense, net of capitalized interest		(246)		(656)
Other, net		60		422
Income and mining tax (expense) benefit		943		1,778
Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent		646		1,413
Income (loss) from discontinued operations		0		0
Assets, Net	[2]	390,155		390,155
Capital expenditures		19,045		37,674
Kensington [Member]
Financial information relating to reporting segments
Revenue		35,735	35,567	72,035	73,531
Costs applicable to sales	[1]	34,227	27,988	62,857	56,431
Amortization		6,441	8,347	13,158	17,525
Exploration		1,395	1,980	2,985	2,819
Loss on debt extinguishments			0		0
Other operating expenses		327	350	648	695
Fair value adjustments, net, pretax		0	0	0	0
Interest expense, net of capitalized interest		(231)	(113)	(474)	(153)
Other, net		(33)	(57)	(70)	(865)
Income and mining tax (expense) benefit		0	0	0	0
Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent		(6,919)	(3,268)	(8,157)	(4,957)
Income (loss) from discontinued operations		0	0	0	0
Assets, Net	[2]	215,753	207,103	215,753	207,103
Capital expenditures		10,708	8,649	22,072	14,170
Wharf [Member]
Financial information relating to reporting segments
Revenue		29,840	27,013	53,273	57,264
Costs applicable to sales	[1]	19,258	15,768	34,567	32,088
Amortization		3,353	2,549	6,010	5,660
Exploration		0	3	10	3
Loss on debt extinguishments			0		0
Other operating expenses		688	632	1,353	1,251
Fair value adjustments, net, pretax		0	0	0	0
Interest expense, net of capitalized interest		(11)	(17)	(23)	(36)
Other, net		64	336	43	425
Income and mining tax (expense) benefit		(1,036)	(1,060)	(1,675)	(2,016)
Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent		5,558	7,320	9,678	16,635
Income (loss) from discontinued operations		0	0	0	0
Assets, Net	[2]	99,878	104,311	99,878	104,311
Capital expenditures		1,162	1,471	1,506	2,358
Other Mining Properties [Member]
Financial information relating to reporting segments
Revenue		0	934	0	1,590
Costs applicable to sales	[1]	0	418	0	705
Amortization		239	469	486	907
Exploration		1,518	2,391	2,598	5,029
Loss on debt extinguishments			(9,342)		(9,342)
Other operating expenses		8,597	8,987	19,005	20,874
Fair value adjustments, net, pretax		(2,462)	0	2,192	0
Interest expense, net of capitalized interest		(5,258)	(3,379)	(10,341)	(6,657)
Other, net		(768)	1,849	1,625	23,028
Income and mining tax (expense) benefit		485	5,372	1,154	7,134
Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent		(18,357)	(16,831)	(27,459)	(11,762)
Income (loss) from discontinued operations		0	(550)	550	(596)
Assets, Net	[2]	115,170	83,338	115,170	83,338
Capital expenditures		$ 102	$ 1,969	$ 184	$ 2,354

[1] Excludes amortization.

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