Retirement Plans and Related Post Retirement Benefits - Assumptions Used to Determine the Net Periodic Cost (Detail) |
12 Months Ended | ||
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Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
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| SERP | |||
| Defined Benefit Plan Disclosure | |||
| Discount Rate | 4.20% | 4.45% | 4.05% |
| Future Average Compensation Increases | 5.00% | ||
| SERP | Minimum | |||
| Defined Benefit Plan Disclosure | |||
| Future Average Compensation Increases | 3.00% | 3.00% | |
| SERP | Maximum | |||
| Defined Benefit Plan Disclosure | |||
| Future Average Compensation Increases | 5.00% | 5.00% | |
| SERP Medical | |||
| Defined Benefit Plan Disclosure | |||
| Discount Rate | 4.20% | 4.45% | 4.05% |
| Future Average Compensation Increases | 5.50% | 5.72% | 5.32% |
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- Definition Weighted average rate for present value of future retirement benefits cash flows, used to determine net periodic benefit cost of defined benefit plan. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition Weighted average rate of compensation increase used to determine net periodic benefit cost of defined benefit plan. Plan includes, but is not limited to, pay-related defined benefit plan. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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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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