Consolidated Condensed Balance Sheets (Parenthetical) - $ / shares	Jan. 31, 2018	Jul. 31, 2017	Jan. 31, 2017
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	45,857,000	45,448,000	45,419,000
Exchangeable Shares, Par Value Per Share	$ 0.01	$ 0.01	$ 0.01
Exchangeable Shares, Shares, Issued	60,000	69,000	73,000
Treasury stock, shares	5,436,000	5,436,000	5,436,000