Note 15 - Income Taxes (Details Textual) $ in Millions	Sep. 30, 2017 USD ($)
Lighting Segment [Member]
Deferred Tax Assets, Goodwill and Intangible Assets	$ 10.7

Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from intangible assets including goodwill.

No definition available.

Name:	us-gaap_DeferredTaxAssetsGoodwillAndIntangibleAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant