Aggregate carrying amount of the estimated litigation liability for known or estimated probable loss from litigation, which may include attorneys' fees and other litigation costs.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=82911808&loc=d3e14326-108349

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.25)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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

Note 10 - Commitments and Contingencies (Details Textual) - USD ($)	May 08, 2017	Mar. 31, 2017	Dec. 31, 2016
Letters of Credit Outstanding, Amount		$ 26,600,000	$ 27,200,000
Pending Litigation [Member]
Estimated Litigation Liability		$ 500,000
Cargo Claim [Member] \| Judicial Ruling [Member] \| Subsequent Event [Member]
Increase (Decrease) in Estimated Litigation Liability	$ 900,000
Estimated Litigation Liability	$ 7,200,000