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v3.19.3.a.u2

Summary of Significant Accounting Policies (Details) $ in Thousands | 12 Months Ended |
--- | --- | ---
Dec. 31, 2019 USD ($) pot_line | Dec. 31, 2018 USD ($)
Schedule of Equity Method Investments [Line Items] |  |
Glencore beneficial ownership | 42.90% |
Glencore economic ownership | 46.90% |
Allowance for doubtful accounts receivable | $ | $ 1,000 | $ 1,000
Property, Plant and Equipment [Line Items] |  |
Number of potlines rebuilt | pot_line | 2 |
Minimum [Member] | Building and Improvements [Member] |  |
Property, Plant and Equipment [Line Items] |  |
Useful life | 10 years |
Minimum [Member] | Machinery and Equipment [Member] |  |
Property, Plant and Equipment [Line Items] |  |
Useful life | 5 years |
Minimum [Member] | Technology and Software [Member] |  |
Property, Plant and Equipment [Line Items] |  |
Useful life | 3 years |
Maximum [Member] | Building and Improvements [Member] |  |
Property, Plant and Equipment [Line Items] |  |
Useful life | 45 years |
Maximum [Member] | Machinery and Equipment [Member] |  |
Property, Plant and Equipment [Line Items] |  |
Useful life | 35 years |
Maximum [Member] | Technology and Software [Member] |  |
Property, Plant and Equipment [Line Items] |  |
Useful life | 7 years |

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