Note 3 - Recent Accounting Pronouncements (Details Textual) $ in Millions	9 Months Ended
Sep. 30, 2017 USD ($)
Reclassification from Net Cash Used in Financing Activities to Net Cash Provided by Operating Activities [Member] \| Three Months Ended March 31, 2016 [Member]
Prior Period Reclassification Adjustment	$ 0.4

The amount of a reclassification adjustment made to prior period financial statement amounts.

No definition available.

Name:	us-gaap_PriorPeriodReclassificationAdjustment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration