Fair value, before effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities elected not to be offset. Excludes liabilities not subject to a master netting arrangement.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 20
-Section 50
-Paragraph 4D
-Subparagraph (c)(2)
-URI http://asc.fasb.org/extlink&oid=121570589&loc=SL51823488-111719

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4B
-Subparagraph (a),(c)
-URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5624163-113959

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 50
-Paragraph 3
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 55
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=99393222&loc=SL20226000-175313

Name:	us-gaap_DerivativeFairValueOfDerivativeLiability
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Derivative Financial Instruments - Summary of Classification of Fair Value on Derivatives Designated as Cash Flow Hedges (Details) - Designated as Hedging Instrument - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Prepaid expenses and other
Derivatives, Fair Value [Line Items]
Fair value of derivative asset	$ 6,779
Accrued liabilities and other
Derivatives, Fair Value [Line Items]
Fair value of derivative liability	14,485
Gold zero cost collars \| Prepaid expenses and other
Derivatives, Fair Value [Line Items]
Fair value of derivative asset	0	$ 0
Gold zero cost collars \| Accrued liabilities and other
Derivatives, Fair Value [Line Items]
Fair value of derivative liability	14,485	$ 136
Foreign Exchange Forward \| Prepaid expenses and other
Derivatives, Fair Value [Line Items]
Fair value of derivative asset	6,779
Foreign Exchange Forward \| Accrued liabilities and other
Derivatives, Fair Value [Line Items]
Fair value of derivative liability	$ 0