Note 8 - Employee Benefit Plans (Details) - Investment Policy Allocation	12 Months Ended
Dec. 31, 2015
Large Cap U.S. Equity [Member]
Note 8 - Employee Benefit Plans (Details) - Investment Policy Allocation [Line Items]
Asset categories	10.00%
Allocation minimum percentage	7.00%
Allocation maximum percentage	13.00%
Small Cap U.S. Equity [Member]
Note 8 - Employee Benefit Plans (Details) - Investment Policy Allocation [Line Items]
Asset categories	5.00%
Allocation minimum percentage	4.00%
Allocation maximum percentage	6.00%
Foreign Government Debt Securities [Member]
Note 8 - Employee Benefit Plans (Details) - Investment Policy Allocation [Line Items]
Asset categories	15.00%
Allocation minimum percentage	11.00%
Allocation maximum percentage	19.00%
Fixed Income Funds [Member]
Note 8 - Employee Benefit Plans (Details) - Investment Policy Allocation [Line Items]
Asset categories	30.00%
Allocation minimum percentage	25.00%
Allocation maximum percentage	35.00%
Real Estate [Member]
Note 8 - Employee Benefit Plans (Details) - Investment Policy Allocation [Line Items]
Asset categories	15.00%
Allocation minimum percentage	12.00%
Allocation maximum percentage	18.00%
Hedge Funds [Member]
Note 8 - Employee Benefit Plans (Details) - Investment Policy Allocation [Line Items]
Asset categories	15.00%
Allocation minimum percentage	12.00%
Allocation maximum percentage	18.00%
Real Return [Member]
Note 8 - Employee Benefit Plans (Details) - Investment Policy Allocation [Line Items]
Asset categories	10.00%
Allocation minimum percentage	8.00%
Allocation maximum percentage	12.00%

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- Definition

Target allocation of investments of this type to total plan assets presented on a weighted average basis.

+ References

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)(i)
-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)(i)
-URI http://asc.fasb.org/extlink&oid=58740216&loc=d3e1928-114920

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Target allocation maximum percentage of investments of this type to total plan assets presented on a weighted average basis.

+ References

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Target allocation minimum percentage of investments of this type to total plan assets presented on a weighted average basis.

+ 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 (d)(i)
-URI http://asc.fasb.org/extlink&oid=58740216&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 5
-Subparagraph (c)(i)
-URI http://asc.fasb.org/extlink&oid=58740216&loc=d3e2446-114920

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