Note 3 - Accumulated Other Comprehensive (Loss) Income (Details Textual) - USD ($) $ in Thousands	Mar. 31, 2018	Jan. 01, 2018
Cumulative Effect of New Accounting Principle in Period of Adoption
Accounting Standards Update 2016-01 [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	$ 56	$ 56

Amount after tax of increase (decrease) to equity or (increase) decrease to net assets, resulting from the cumulative effect adjustment of a new accounting principle applied in the period of adoption.

No definition available.

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