5. Income Taxes (Details - Deferred Income Tax Assets and Liabilities) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Deferred tax assets:
Benefit plans	$ 1,958	$ 1,535
Inventories	473	483
Other	733	158
Total deferred tax assets	3,164	2,176
Deferred tax liabilities:
Property, plant and equipment	9,585	9,648
Patents and goodwill	2,897	2,926
Other	91	158
Total deferred tax liabilities	12,573	12,732
Net deferred tax liability	9,409	10,556
Balance Sheet classification:
Non-current deferred income tax liability	9,989	11,129
Current deferred income tax asset	580	573
Net deferred tax liability	$ 9,409	$ 10,556