SELECTED QUARTERLY FINANCIAL DATA (UNAUDITED) (Details) (USD $)	3 Months Ended										12 Months Ended
	Dec. 31, 2012		Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011		Mar. 31, 2011	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Selected quarterly financial data [Abstract]
Net sales	$ 71,752,000	[1]	$ 76,059,000	$ 73,222,000	$ 65,561,000	$ 68,642,000	$ 75,903,000	$ 79,173,000	[2]	$ 71,403,000	$ 286,594,000		$ 295,121,000		$ 302,539,000
Cost of sales	60,505,000	[1]	63,404,000	61,051,000	55,132,000	58,384,000	63,865,000	65,368,000	[2]	57,132,000	240,092,000		244,749,000		239,185,000
Net earnings	(2,537,000)	[1]	2,600,000	1,463,000	876,000	82,000	1,012,000	(574,000)	[2]	3,244,000	2,402,000		3,764,000		13,649,000
Earnings (loss) per share [Abstract]
Litigation charges								2,800,000
Litigation charges after tax								2,600,000
Restructuring charges	3,100,000										5,245,000		314,000		0
Class A [Member]
Selected quarterly financial data [Abstract]
Net earnings											377,000		620,000		2,394,000
Earnings (loss) per share [Abstract]
Common share - basic and diluted (in dollars per share)	$ (0.21)	[1]	$ 0.20	$ 0.11	$ 0.07	$ 0.00	$ 0.08	$ (0.05)	[2]	$ 0.26	$ 0.17	[3]	$ 0.28	[3]	$ 1.10
Class B [Member]
Selected quarterly financial data [Abstract]
Net earnings											$ 2,025,000		$ 3,144,000		$ 11,255,000
Earnings (loss) per share [Abstract]
Common share - basic and diluted (in dollars per share)	$ (0.22)	[1]	$ 0.22	$ 0.13	$ 0.08	$ 0.01	$ 0.09	$ (0.05)	[2]	$ 0.28	$ 0.21	[3]	$ 0.33	[3]	$ 1.18

[1] The net loss for the quarter ended December 31, 2012 includes $3.1 million of restructuring charges primarily related to severance charges and the writedown of assets associated with the closure of the Company's Vinita, Oklahoma manufacturing facility.

[2] The net loss for the quarter ended June 30, 2011 includes $2.8 million of net litigation charges related to the SynQor and Halo lawsuits ($2.6 million after tax).

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