Note 14 - Benefit Plans - Components of Net Periodic (Benefit) Cost (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Interest cost	$ 2,688	$ 2,747	$ 2,681
Expected return on plan assets	(3,011)	(2,868)	(3,041)
Amortization of net loss	883	941	1,228
Net periodic pension cost	$ 560	$ 820	$ 868

Amount of gain (loss) recognized in net periodic benefit (cost) credit of defined benefit plan.

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- Definition

Amount of expected return (loss) recognized in net periodic benefit (cost) credit, calculated based on expected long-term rate of return and market-related value of plan assets of defined benefit plan.

+ References

+ Details

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- Definition

Amount of cost recognized for passage of time related to defined benefit plan.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (h)(2)
-URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (a)(2)
-URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920

+ Details

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- Definition

Amount of net periodic benefit cost (credit) for defined benefit plan.

+ References

+ Details

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