Condensed Consolidated Balance Sheet Parenthetical (USD $) In Thousands, except Share data, unless otherwise specified	Apr. 30, 2012	Jul. 31, 2011
Current Assets
Allowance for doubtful accounts	$ 638	$ 607
Other Assets
Accumulated amortization Trademarks and patents	401	381
Accumulated amortization Debt issuance costs	392	333
Accumulated amortization Licensing and non-compete agreements	$ 1,548	$ 1,361
Common Stock
Stockholder's Equity
Common stock, par value (in dollars per share)	$ 0.10	$ 0.10
Common stock, shares issued	7,770,188	7,750,324
Treasury stock, common shares	2,730,947	2,642,387
Common Class B
Stockholder's Equity
Common stock, par value (in dollars per share)	$ 0.10	$ 0.10
Common stock, shares issued	2,374,859	2,372,859
Treasury stock, common shares	324,741	324,741