Summary of Activity for Time-Based Stock Awards (Detail) - Time Based Stock Awards	6 Months Ended
	Jan. 31, 2018 $ / shares shares
Non-vested Shares
Beginning balance, Non-vested | shares	173,603
Granted | shares	6,100	[1]
Vested | shares	(15,672)	[2]
Forfeited | shares	(385)
Ending balance, Non-vested | shares	163,646
Weighted-Average Grant-Date Fair Value
Beginning balance, Non-vested | $ / shares	$ 24.37
Granted | $ / shares	56.69	[1]
Vested | $ / shares	37.48	[2]
Forfeited | $ / shares	31.39
Ending balance, Non-vested | $ / shares	$ 24.30

[1] Includes 4,100 shares granted to non-employee directors for service during the six months ended January 31, 2018.

[2] Includes 4,100 shares granted to non-employee directors for service for the six months ended January 31, 2018. The shares vest on the date of grant, and the Company recognizes compensation expense on such date. Includes 11,572 time-based RSU awards granted to certain employees and executives, and the Company recognizes compensation expense related to the awards over the respective service periods in accordance with GAAP. Upon vesting, each RSU was converted to one share of common stock.