CONSOLIDATED STATEMENTS OF OPERATIONS (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Net sales	$ 349,189	[1]	$ 286,594	[1]	$ 295,121
Costs and expenses:
Cost of sales	286,952	[1]	240,115	[1]	244,749
Selling, general and administrative	45,831		39,362		39,284
Litigation charges	41		26		3,471
Restructuring charges	1,387		5,245		314
(Gain) loss on disposal/sale of property, plant and equipment	(69)		183		(93)
Total costs and expenses	334,142		284,931		287,725
Income from operations	15,047		1,663		7,396
Impairment of investment	0		(775)		0
Gain (loss) on sale of investments	98		(142)		119
Interest expense	(156)		(16)		0
Interest income and other, net	176		267		357
Earnings before (benefit) provision for income taxes	15,165		997		7,872
(Benefit) provision for income taxes	(743)		(1,376)		4,108
Net earnings	15,908	[1]	2,373	[1]	3,764
Class A [Member]
Costs and expenses:
Net earnings	2,868		372		620
Earnings per share:
Common share - basic and diluted (in dollars per share)	$ 1.32	[1]	$ 0.17	[1]	$ 0.28
Weighted-average shares outstanding:
Common share - basic and diluted (in shares)	2,174,912		2,174,912		2,174,912
Dividends paid per share:
Common share (in dollars per share)	$ 0.24		$ 0.24		$ 0.24
Class B [Member]
Costs and expenses:
Net earnings	$ 13,040		$ 2,001		$ 3,144
Earnings per share:
Common share - basic and diluted (in dollars per share)	$ 1.41	[1]	$ 0.21	[1]	$ 0.33
Weighted-average shares outstanding:
Common share - basic and diluted (in shares)	9,239,646		9,624,578		9,597,661
Dividends paid per share:
Common share (in dollars per share)	$ 0.28		$ 0.28		$ 0.28

[1] Quarterly amounts of earnings per share may not agree to the total for the year due to rounding.