Business Segments - Summary of company's operations (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Segment Reporting Information [Line Items]
Revenues from unaffiliated customers	$ 7,995	$ 8,067	$ 14,985	$ 15,409
Cost of goods sold, exclusive of depreciation and amortization	(5,850)	(5,873)	(11,288)	(11,570)
Selling, general and administrative	(1,343)	(1,335)	(2,919)	(2,634)
Interest expense	(10)	(11)	(19)	(21)
Depreciation and amortization	(171)	(155)	(340)	(308)
Other income, net	11		12	1
Income (loss) before income tax provision (benefit)	632	693	431	877
Income tax (benefit) provision	185	189	129	196
Net income (loss)	447	504	302	681
Capital expenditures			877	989
Operating Segments
Segment Reporting Information [Line Items]
Revenues from unaffiliated customers	7,995	8,067	14,985	15,409
Cost of goods sold, exclusive of depreciation and amortization	(5,850)	(5,873)	(11,288)	(11,570)
Selling, general and administrative	(1,343)	(1,335)	(2,919)	(2,634)
Interest expense	(10)	(11)	(19)	(21)
Depreciation and amortization	(171)	(155)	(340)	(308)
Other income, net	11		12	1
Income (loss) before income tax provision (benefit)	632	693	431	877
Income tax (benefit) provision	185	189	129	196
Net income (loss)	447	504	302	681
Capital expenditures	459	511	877	989
Operating Segments | ATG
Segment Reporting Information [Line Items]
Revenues from unaffiliated customers	6,254	5,806	11,559	11,189
Cost of goods sold, exclusive of depreciation and amortization	(4,347)	(4,121)	(8,187)	(8,107)
Selling, general and administrative	(1,042)	(908)	(2,182)	(1,798)
Interest expense	(10)	(11)	(19)	(21)
Depreciation and amortization	(123)	(111)	(245)	(219)
Other income, net	10		10
Income (loss) before income tax provision (benefit)	742	655	936	1,044
Income tax (benefit) provision	226	181	280	241
Net income (loss)	516	474	656	803
Capital expenditures	81	429	453	813
Operating Segments | CPG
Segment Reporting Information [Line Items]
Revenues from unaffiliated customers	1,741	2,261	3,426	4,220
Cost of goods sold, exclusive of depreciation and amortization	(1,503)	(1,752)	(3,101)	(3,463)
Selling, general and administrative	(301)	(427)	(737)	(836)
Interest expense
Depreciation and amortization	(48)	(44)	(95)	(89)
Other income, net	1		2	1
Income (loss) before income tax provision (benefit)	(110)	38	(505)	(167)
Income tax (benefit) provision	(41)	8	(151)	(45)
Net income (loss)	(69)	30	(354)	(122)
Capital expenditures	$ 378	$ 82	$ 424	$ 176