Note 10 - Contingencies (Details Textual) $ in Millions	Dec. 31, 2017 USD ($)
Brazilian Program of Social Integration (PIS) Tax Dispute [Member] \| Other Nonoperating Income (Expense) [Member]
Former Gain Contingency, Recognized in Current Period	$ 1

Amount of gain recognized in the period that had been disclosed in prior periods as a contingent gain.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 30
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6397426&loc=d3e17499-108355

Name:	us-gaap_FormerGainContingencyRecognizedInCurrentPeriod
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant