Consolidated Condensed Balance Sheets (Parenthetical) - $ / shares	Jan. 31, 2016	Jul. 31, 2015	Jan. 31, 2015
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01	$ 0.01
Preferred stock, shares authorized	25,000,000	25,000,000	25,000,000
Preferred stock, shares issued	0	0	0
Preferred stock, shares outstanding	0	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01	$ 0.01
Common stock, shares authorized	100,000,000	100,000,000	100,000,000
Common stock, shares issued	41,578,019	41,462,941	41,294,906
Treasury stock, shares	5,326,941	4,949,111	4,949,111