Earning Per Common Share (Detail) - shares	3 Months Ended		6 Months Ended
	Jan. 31, 2018	Jan. 31, 2017	Jan. 31, 2018	Jan. 31, 2017
Earnings Per Share [Abstract]
Weighted-average shares outstanding for basic earnings per share	52,694,680	52,582,134	52,653,303	52,543,050
Unvested restricted stock and restricted stock units	166,460	158,825	186,449	180,400
Weighted-average shares outstanding assuming dilution	52,861,140	52,740,959	52,839,752	52,723,450