CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (Unaudited) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Net sales	$ 93,981	$ 73,222	$ 157,009	$ 138,783
Costs and expenses:
Cost of sales	78,041	61,081	131,959	116,218
Selling, general and administrative	12,129	9,563	22,522	18,421
Restructuring charge	1,263	245	1,387	382
Total costs and expenses	91,433	70,889	155,868	135,021
Income from operations	2,548	2,333	1,141	3,762
Impairment of investment	0	(478)	0	(478)
Interest expense	(3)	0	(6)	0
Interest income and other, net	69	77	109	153
Earnings before provision (benefit) for income taxes	2,614	1,932	1,244	3,437
Provision (benefit) for income taxes	187	491	(640)	1,124
Net earnings	2,427	1,441	1,884	2,313
Class A [Member]
Costs and expenses:
Net earnings	434	242	325	384
(Loss) earnings per share:
Common share - basic and diluted (in dollars per share)	$ 0.20	$ 0.11	$ 0.15	$ 0.18
Weighted-average shares outstanding:
Common share - basic and diluted (in shares)	2,174,912	2,174,912	2,174,912	2,174,912
Dividends paid per share:
Common share (in dollars per share)	$ 0.06	$ 0.06	$ 0.12	$ 0.12
Class B [Member]
Costs and expenses:
Net earnings	$ 1,993	$ 1,199	$ 1,559	$ 1,929
(Loss) earnings per share:
Common share - basic and diluted (in dollars per share)	$ 0.22	$ 0.12	$ 0.17	$ 0.20
Weighted-average shares outstanding:
Common share - basic and diluted (in shares)	9,213,178	9,677,141	9,217,119	9,654,473
Dividends paid per share:
Common share (in dollars per share)	$ 0.07	$ 0.07	$ 0.14	$ 0.14