Condensed Consolidated Balance Sheet Parenthetical - USD ($) $ in Thousands	Oct. 31, 2017	Jul. 31, 2017
Current Assets
Allowance for doubtful accounts	$ 726	$ 748
Other Assets
Accumulated amortization of trademarks and patents	244	238
Accumulated amortization of customer lists	4,835	4,601
Noncurrent Liabilities
Net unamortized debt issuance costs	$ 82	$ 89
Common Stock
Stockholder's Equity
Common stock, par value (in dollars per share)	$ 0.10	$ 0.10
Common stock, shares issued	8,045,606	8,015,166
Treasury stock, common shares	2,908,992	2,907,370
Common Class B
Stockholder's Equity
Common stock, par value (in dollars per share)	$ 0.10	$ 0.10
Common stock, shares issued	2,507,122	2,513,512
Treasury stock, common shares	324,741	324,741