Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Jul. 31, 2019	Jul. 31, 2018	Jul. 31, 2017
Statement of Financial Position [Abstract]
Trade receivables, allowances	$ 724	$ 1,278
Inventories, reserves	$ 2,031	$ 1,534
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01	$ 0.01
Preferred stock, shares authorized	25,000,000	25,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	46,190,000	46,021,000
Exchangeable Shares, Shares, Issued	56,000	58,000
Treasury stock, shares	5,905,000	5,552,000