Income Taxes (Schedule Of Deferred Tax Assets And Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Income Taxes [Abstract]
Insurance (primarily product liability)	$ 1,023	$ 1,594
Inventory	654	628
Vacation	596	893
Doubtful accounts	447	2,878
Environmental	275	320
Deferred compensation	253	338
Other	72	110
Total deferred tax assets	3,320	6,761
Goodwill and other intangibles	1,112	1,698
Deferred revenue	875
Depreciation	338	8,067
Total deferred tax liabilities	2,325	9,765
Net deferred tax assets	$ 995
Net deferred tax (liabilities)		$ (3,004)