Fair Value Measurement - Realized Unrealized Derivatives, net (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Derivatives, Fair Value [Line Items]
Realized (loss) gain	$ 1,160	$ 359	$ 2,026	$ 450
Unrealized gain (loss)	(3,324)	310	(2,156)	184
Total realized/ unrealized derivatives, net	(2,164)	669	(130)	634
Gold
Derivatives, Fair Value [Line Items]
Realized (loss) gain	56	21	182	(23)
Unrealized gain (loss)	(243)	130	(1)	30
Total realized/ unrealized derivatives, net	(187)	151	181	7
Silver.
Derivatives, Fair Value [Line Items]
Realized (loss) gain	(95)	87	154	172
Unrealized gain (loss)	(164)	103	111	21
Total realized/ unrealized derivatives, net	(259)	190	265	193
Copper
Derivatives, Fair Value [Line Items]
Realized (loss) gain	(58)	62	(15)	67
Unrealized gain (loss)	(121)	(47)	(105)	(8)
Total realized/ unrealized derivatives, net	(179)	15	(120)	59
Lead
Derivatives, Fair Value [Line Items]
Realized (loss) gain	37	30	56	74
Unrealized gain (loss)	(246)	87	(199)	21
Total realized/ unrealized derivatives, net	(209)	117	(143)	95
Zinc
Derivatives, Fair Value [Line Items]
Realized (loss) gain	1,220	159	1,649	160
Unrealized gain (loss)	(2,550)	37	(1,962)	120
Total realized/ unrealized derivatives, net	$ (1,330)	$ 196	$ (313)	$ 280

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Net Increase or Decrease in the fair value of the embedded derivative or group of embedded derivatives included in earnings in the period.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 15
-URI http://asc.fasb.org/subtopic&trid=2229187

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- Definition

The difference between the book value and the sale price of options, swaps, futures, forward contracts, and other derivative instruments. This element refers to the gain (loss) included in earnings.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123570139&loc=d3e3602-108585

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 220
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04.13(h))
-URI http://asc.fasb.org/extlink&oid=120399700&loc=SL114874048-224260

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The net change in the difference between the fair value and the carrying value, or in the comparative fair values, of derivative instruments, including options, swaps, futures, and forward contracts, held at each balance sheet date, that was included in earnings for the period.

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