6. Segment Information (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015
Net Sales:
Customer sales									$ 38,456,000	$ 37,059,000
Intercompany sales									0	0
Total Net Sales	$ 8,998,000	$ 10,036,000	$ 9,850,000	$ 9,572,000	$ 7,993,000	$ 8,988,000	$ 9,963,000	$ 10,115,000	38,456,000	37,059,000
Share based compensation									170,000	133,000
Depreciation									2,561,000	2,863,000
Interest (income) expense									177,000	208,000
Income tax (benefit) expense	(58,000)	$ 142,000	$ (52,000)	$ 75,000	442,000	$ 22,000	$ (73,000)	$ (81,000)	107,000	310,000
Location profit (loss)									444,000	(6,364,000)
Capital expenditures									1,203,000	6,017,000
Location long-lived assets	15,907,000				17,472,000				15,907,000	17,472,000
Location assets	35,729,000				36,708,000				35,729,000	36,708,000
Inter-Company Eliminations [Member]
Net Sales:
Customer sales									0	0
Intercompany sales									(11,990,000)	(10,178,000)
Total Net Sales									(11,990,000)	(10,178,000)
Share based compensation									0	0
Depreciation									0	0
Interest (income) expense									0	0
Income tax (benefit) expense									(9,000)	16,000
Location profit (loss)									(10,000)	58,000
Capital expenditures									0	0
Location long-lived assets	0				0				0	0
Location assets	(714,000)				(1,419,000)				(714,000)	(1,419,000)
United States (Corpus Christi) [Member]
Net Sales:
Customer sales									26,678,000	25,646,000
Intercompany sales									98,000	37,000
Total Net Sales									26,776,000	25,683,000
Share based compensation									170,000	133,000
Depreciation									1,076,000	1,011,000
Interest (income) expense									(2,000)	13,000
Income tax (benefit) expense									(131,000)	(318,000)
Location profit (loss)									(406,000)	(760,000)
Capital expenditures									463,000	1,335,000
Location long-lived assets	5,291,000				5,904,000				5,291,000	5,904,000
Location assets	17,013,000				16,449,000				17,013,000	16,449,000
European (TPT) [Member]
Net Sales:
Customer sales									9,313,000	8,619,000
Intercompany sales									7,357,000	4,309,000
Total Net Sales									16,670,000	12,928,000
Share based compensation									0	0
Depreciation									1,343,000	1,174,000
Interest (income) expense									107,000	25,000
Income tax (benefit) expense									247,000	(69,000)
Location profit (loss)									826,000	(225,000)
Capital expenditures									735,000	4,676,000
Location long-lived assets	9,832,000				10,618,000				9,832,000	10,618,000
Location assets	13,417,000				13,617,000				13,417,000	13,617,000
Asian (TMM) [Member]
Net Sales:
Customer sales									2,465,000	2,794,000
Intercompany sales									4,535,000	5,832,000
Total Net Sales									7,000,000	8,626,000
Share based compensation									0	0
Depreciation									142,000	678,000
Interest (income) expense									72,000	170,000
Income tax (benefit) expense									0	681,000
Location profit (loss)									34,000	(5,437,000)
Capital expenditures									5,000	6,000
Location long-lived assets	784,000				950,000				784,000	950,000
Location assets	$ 6,013,000				$ 8,061,000				$ 6,013,000	$ 8,061,000