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Employee Benefit Plan (Details) | 12 Months Ended
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Dec. 31, 2018 USD ($) ExecutiveOfficers | Dec. 31, 2017 USD ($) | Dec. 31, 2016 USD ($)
Profit Sharing and 401(k) Plan for eligible employees [Member] |  |  |
Employee Benefit Plan (Textual) |  |  |
Defined benefit plan, annual cost | $ 587,000 | $ 476,000 | $ 356,000
Supplemental Executive Retirement Plan (nonqualified deferred compensation plan) [Member] |  |  |
Employee Benefit Plan (Textual) |  |  |
Defined benefit plan, annual cost | $ 940,000 | 792,000 | $ 782,000
Number of executive officers | ExecutiveOfficers | 20 |  |
Accrued benefit obligation | $ 6,100,000 | $ 5,400,000 |

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