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Retirement Plans - Narrative (Details) $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2020 USD ($) plan | Dec. 31, 2019 USD ($)
Defined Benefit Plan Disclosure |  |
Net loss to be recognize during the next fiscal period | $ 24 |
United States |  |
Defined Benefit Plan Disclosure |  |
Defined benefit plans, estimated future employer contributions in current fiscal year | $ 1,000 |
Pension Plan |  |
Defined Benefit Plan Disclosure |  |
Defined contribution plan number | plan | 6 |
Pension Plan | United States |  |
Defined Benefit Plan Disclosure |  |
Number of retirement plans | plan | 3 |
Number of defined benefit plans | plan | 1 |
Defined contribution plan number | plan | 2 |
Accrued pension obligation | $ 3,989 | $ 3,449
Defined benefit plan, contributions | $ 300 | 550
Pension Plan | Canada |  |
Defined Benefit Plan Disclosure |  |
Defined contribution plan number | plan | 2 |
Pension Plan | United Kingdom |  |
Defined Benefit Plan Disclosure |  |
Defined contribution plan number | plan | 2 |
Defined benefit plans, estimated future employer contributions in current fiscal year | $ 337 |
Accrued pension obligation | 2,290 | 1,811
Defined benefit plan, contributions | $ 337 | 314
Other Postretirement Benefits Plan |  |
Defined Benefit Plan Disclosure |  |
Service period | 10 years |
Other Postretirement Benefits Plan | Rail Technologies |  |
Defined Benefit Plan Disclosure |  |
Accrued pension obligation | $ 932 | $ 840

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