Note 10 - Employee Benefit Plans - Benefit Payments (Details) - Norwegian Pension Plan [Member] $ in Thousands	Dec. 31, 2017 USD ($)
2018	$ 254
2019	254
2020	254
2021	255
2022	255
Total	$ 1,272

Future benefit payments which are expected in defined benefit plan.

No definition available.

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- Definition

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

+ 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 (f)
-URI http://asc.fasb.org/extlink&oid=82843861&loc=d3e1928-114920

+ Details

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- Definition

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

+ References

+ Details

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- Definition

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

+ References

+ Details

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- Definition

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

+ References

+ Details

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- Definition

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

+ References

+ Details

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- Details

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