CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (Unaudited) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Net sales	$ 101,164	$ 76,059	$ 258,173	$ 214,842
Costs and expenses:
Cost of sales	80,730	63,472	212,699	179,690
Selling, general and administrative	12,106	9,929	34,657	28,350
Restructuring charge	0	1,778	1,387	2,160
Total costs and expenses	92,836	75,179	248,743	210,200
Income from operations	8,328	880	9,430	4,642
Gain on sale of investment	98	0	98	0
Impairment of investment	0	(297)	0	(775)
Interest expense	(67)	0	(75)	0
Interest income and other, net	82	63	189	216
Earnings before provision (benefit) for income taxes	8,441	646	9,642	4,083
Provision (benefit) for income taxes	605	(1,845)	(47)	(721)
Net earnings	7,836	2,491	9,689	4,804
Class A [Member]
Costs and expenses:
Net earnings	1,424	426	1,744	811
(Loss) earnings per share:
Common share - basic and diluted (in dollars per share)	$ 0.65	$ 0.20	$ 0.80	$ 0.37
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	$ 0.18	$ 0.18
Class B [Member]
Costs and expenses:
Net earnings	$ 6,412	$ 2,065	$ 7,945	$ 3,993
(Loss) earnings per share:
Common share - basic and diluted (in dollars per share)	$ 0.69	$ 0.21	$ 0.86	$ 0.41
Weighted-average shares outstanding:
Common share - basic and diluted (in shares)	9,228,731	9,697,097	9,221,032	9,668,785
Dividends paid per share:
Common share (in dollars per share)	$ 0.07	$ 0.07	$ 0.21	$ 0.21