Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Apr. 30, 2016	Jul. 31, 2015
Stockholders’ equity:
Preferred stock, par value (in dollars per share)	$ 0.10	$ 0.10
Preferred stock, shares authorized (in shares)	2,000,000	2,000,000
Preferred stock, shares issued (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.10	$ 0.10
Common stock, shares authorized (in shares)	100,000,000	100,000,000
Common stock, shares issued (in shares)	31,204,396	31,165,401
Treasury stock, shares (in shares)	15,033,317	15,033,317