Earnings Per Common Share (Detail) - shares	3 Months Ended		6 Months Ended
	Jan. 31, 2017	Jan. 31, 2016	Jan. 31, 2017	Jan. 31, 2016
Earnings Per Share [Abstract]
Weighted-average common shares outstanding for basic earnings per common share	52,582,134	52,474,801	52,543,050	52,442,373
Unvested restricted stock and restricted stock units	158,825	86,321	180,400	110,968
Weighted-average common shares outstanding for diluted earnings per common share	52,740,959	52,561,122	52,723,450	52,553,341