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Commitments and Contingent Liabilities - Narratives (Details) $ in Thousands |  | 12 Months Ended |  |
--- | --- | --- | --- | ---
Mar. 13, 2019 USD ($) | Dec. 31, 2020 USD ($) company | Dec. 31, 2019 USD ($) | Dec. 31, 2018 USD ($) | Sep. 04, 2020 USD ($) | Jun. 05, 2017 company
Product Liability Contingency |  |  |  |  |  |
Legal fees |  | $ 0 | $ 0 | $ 43,400 |  |
Current portion of accrued settlement |  | 8,000 | 8,000 |  |  |
Accrued legal settlement, non-current |  | 24,000 | $ 32,000 |  |  |
Number Of Companies Receiving General Notice Letter | company |  |  |  |  |  | 140
Present value or proposed remedial work |  | 1,100,000 |  |  |  |
Undiscovered remedial work |  | $ 1,700,000 |  |  |  |
Remedial work anticipated clean up period |  | 13 years |  |  |  |
Number of potentially responsible parties included in agreement | company |  | 100 |  |  |  |
Accrual for environmental loss contingencies, obligations removed |  |  |  |  | $ 3,460 |
Uprr |  |  |  |  |  |
Product Liability Contingency |  |  |  |  |  |
Purchase commitment | $ 48,000 |  |  |  |  |
Annual commitment amount | 8,000 |  |  |  |  |
Uprr |  |  |  |  |  |
Product Liability Contingency |  |  |  |  |  |
Litigation settlement amount |  | $ 32,000 |  | 50,000 |  |
Litigation settlement amount, current | 2,000 |  |  |  |  |
Litigation settlement amount, non-current | 48,000 |  |  |  |  |
Amounts reclassified to accrued settlement | $ 6,600 |  |  |  |  |
Legal fees |  | $ 43,400 |  |  |  |
Rail Technologies and Services |  |  |  |  |  |
Product Liability Contingency |  |  |  |  |  |
Product warranty expense |  |  |  | $ 611 |  |

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