Note 12 - Pension and Other Postretirement Benefits - Assumptions Used to Determine the Retirement Plan Benefit Obligations (Details) - Retirement Plan [Member]	Dec. 31, 2016	Dec. 31, 2015
Weighted average discount rate	3.88%	4.06%
Rate of increase in future compensation levels

Expected rate of compensation increases (for pay-related plans).

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (k)(2)
-URI http://asc.fasb.org/extlink&oid=65897934&loc=d3e1928-114920

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