Contingent Liabilities and Commitments - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Jul. 31, 2018	Jul. 31, 2017
Commitments and Contingencies Disclosure [Abstract]
Standby Repurchase Obligations Amount	$ 2,748,465	$ 2,200,544
Term of Commitments	Up to eighteen months
Repurchase and guarantee reserve balances	$ 7,400	$ 6,345