Consolidated Balance Sheets (Parenthetical) (USD $)
In Thousands, except Share data, unless otherwise specified
Mar. 31, 2012
Dec. 31, 2011
Accounts receivable, allowance for doubtful accounts $ 273 $ 236
Inventory, provision $ 568 $ 578
Preferred stock, no par value      
Preferred stock, shares authorized 3,000 3,000
Preferred stock, shares issued 0 0
Treasury stock, shares 1,562 1,562
Class A Common Stock [Member]
   
Common stock, no par value      
Common stock, shares authorized 30,000 30,000
Common stock, shares issued 16,881 16,691
Common stock, shares outstanding 15,320 15,143
Class B Common Stock [Member]
   
Common stock, no par value      
Common stock, shares authorized 5,000 5,000
Common stock, shares issued 0 0