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Employee Benefits - Benefit Plans and Related Amounts Recorded in Consolidated Balance Sheets (Details) - USD ($) $ in Thousands | 12 Months Ended |  |  |
--- | --- | --- | --- | ---
Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2017
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Abstract] |  |  |  |
Projected benefit obligation | $ 62,297 | $ 52,503 | $ 44,890 | $ 45,450
Pension plan assets at fair value | (28,636) | (23,444) | (19,460) | $ (18,475)
Funded status – shortfall | 33,661 | 29,059 | 25,430 |
Accumulated benefit obligation | 58,963 | 49,485 | 42,611 |
Amounts recorded in the Consolidated Balance Sheets for the plans |  |  |  |
Other liabilities — accrued pension obligation | 33,661 | 29,059 | 25,430 |
Stockholders’ equity — deferred actuarial loss | $ (9,309) | $ (8,584) | $ (5,738) |
Future long-term rate of return on plan assets | 1.19% |  |  |
Weighted average amortization period | 14 years |  |  |

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