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Note 11 - Pension Plan and Other Postretirement Benefits - Weighted-average Assumptions Used to Determine Benefit Obligations (Details) | Dec. 31, 2019 | Dec. 31, 2018
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Pension Plan [Member] |  |
Discount Rate | 3.47% | 4.50%
Pension Plan [Member] | Participants to Age 39 [Member] |  |
Rate of Increase in Future Compensation Level | 4.50% | 4.50%
Pension Plan [Member] | Participants Age 40 to 49 [Member] |  |
Rate of Increase in Future Compensation Level | 3.50% | 3.50%
Pension Plan [Member] | Participants Age 50 and Older [Member] |  |
Rate of Increase in Future Compensation Level | 2.75% | 2.75%
Executive Survivor and Supplemental Retirement Plan [Member] |  |
Discount Rate | 3.36% | 4.46%
Rate of Increase in Future Compensation Level | 3.50% | 3.40%
Other Postretirement Benefits Plan [Member] |  |
Discount Rate | 3.43% | 4.44%

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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. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (k)(1) -URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920 + Details
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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. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (k)(2) -URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920 + Details
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- Details
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- Details
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- Details
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