Note 11 - Pension Plan and Other Postretirement Benefits - Benefit Payments, Which Reflect Expected Future Service, As Appropriate, Expected to Be Paid Out From Plan Assets (Details) $ in Thousands	Dec. 31, 2018 USD ($)
2019	$ 15,086
2020	15,689
2021	16,356
2022	17,017
2023	17,709
2024-2028	96,186
Executive Survivor and Supplemental Retirement Plan [Member]
2019	1,468
2020	1,527
2021	1,618
2022	2,214
2023	2,635
2024-2028	14,215
Other Postretirement Benefits Plan [Member]
2019	4,247
2020	4,322
2021	4,483
2022	4,698
2023	4,781
2024-2028	$ 24,183

Amount of benefits for defined benefit plan expected to be paid in five fiscal years after fifth fiscal year following latest fiscal year.

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 (f)
-URI http://asc.fasb.org/extlink&oid=108410482&loc=d3e1928-114920

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Amount of benefits for defined benefit plan expected to be paid in next fiscal year following latest fiscal year.

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