Retirement Plans and Related Post Retirement Benefits - Assumptions Used to Calculate the Post Retirement Benefit Obligation (Details)  | 
Dec. 31, 2019  | 
Dec. 31, 2018  | 
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| SERP | ||
| Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | ||
| Discount Rate | 3.17% | 4.20% | 
| Future Average Compensation Increases | 2.00% | 2.00% | 
| SERP Medical | ||
| Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | ||
| Discount Rate | 3.17% | 4.20% | 
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- Definition Weighted average rate for present value of future retirement benefits cash flows, used to determine benefit obligation of defined benefit plan. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
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- Definition Weighted average rate increase of compensation, used to determine benefit obligation of defined benefit plan. Plan includes, but is not limited to, pay-related defined benefit plan. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef 
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available. 
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