Note 12 - Pension and Other Postretirement Benefit Plans (Details) - The Retirement Plan’s Weighted Average Asset Allocations - Retirement Plan [Member]	Dec. 31, 2015	Dec. 31, 2014
Equity Securities [Member]
Note 12 - Pension and Other Postretirement Benefit Plans (Details) - The Retirement Plan’s Weighted Average Asset Allocations [Line Items]
Weighted average asset allocation	70.00%	68.00%
Debt Securities [Member]
Note 12 - Pension and Other Postretirement Benefit Plans (Details) - The Retirement Plan’s Weighted Average Asset Allocations [Line Items]
Weighted average asset allocation	30.00%	32.00%

Percentage of fair value of investments (categorized by debt securities, equity securities, real estate and other plan assets) to the fair value of plan assets held.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 5
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=58740216&loc=d3e2446-114920

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (d)(1)
-URI http://asc.fasb.org/extlink&oid=58740216&loc=d3e1928-114920

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