Note 7 - Taxes on Income - Deferred Income Tax Asset (Liability) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Deferred income tax assets:
Pension accruals	$ 2,606	$ 3,581
Operating reserves and other accruals	2,174	3,656
Tax carrying value in excess of book basis of goodwill	866	1,377
Tax credits	255	99
Valuation allowance on tax credits	(255)
Deferred income tax liabilities:
Book carrying value in excess of tax basis of property	(937)	(827)
Deferred expenses	(1,809)	(1,086)
Net deferred income tax asset	$ 2,900	$ 6,800