The aggregate amount of write-downs for impairments recognized during the period for long lived assets held for use (including those held for disposal by means other than sale).

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
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Name:	us-gaap_ImpairmentOfLongLivedAssetsHeldForUse
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Summary of Significant Accounting Policies (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Nature of Operations
Ownership percentage of subsidiaries	100.00%
Impairment of Long-Lived Assets Held-for-use	$ 0	$ 0
Buildings \| Minimum
Other Current Liabilities
Useful life	30 years
Buildings \| Maximum
Other Current Liabilities
Useful life	40 years
Mining equipment and machinery \| Minimum
Other Current Liabilities
Useful life	3 years
Mining equipment and machinery \| Maximum
Other Current Liabilities
Useful life	8 years
Other furniture and equipment \| Minimum
Other Current Liabilities
Useful life	3 years
Other furniture and equipment \| Maximum
Other Current Liabilities
Useful life	5 years