Note 15 - Commitments and Contingencies (Details Textual) $ in Millions	9 Months Ended
Sep. 30, 2017 USD ($)
Letters of Credit Issued and Available Amount	$ 2.5
Standby Letters of Credit [Member]
Line of Credit Facility, Expiration Period	3 years

Period remaining on line of credit facility before it terminates, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

No definition available.

Name:	us-gaap_LineOfCreditFacilityExpirationPeriod
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration