Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Jul. 31, 2018	Jul. 31, 2017
Statement of Financial Position [Abstract]
Trade receivables, allowances	$ 1,278	$ 750
Inventories, reserves	$ 1,534	$ 1,518
Preferred stock, par value (in dollars per share)	$ 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	46,021,000	45,448,000
Exchangeable Shares, Shares, Issued	58,000	69,000
Treasury stock, shares	5,552,000	5,436,000