Consolidated Condensed Balance Sheets (Parenthetical) - $ / shares	Apr. 30, 2019	Jul. 31, 2018	Apr. 30, 2018
Preferred Stock, Par or Stated Value 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	46,105,000	46,021,000	45,874,000
Exchangeable Shares, Par Value Per Share	$ 0.01	$ 0.01	$ 0.01
Exchangeable Shares, Shares, Issued	56,000	58,000	58,000
Treasury stock, shares	5,905,000	5,552,000	5,552,000