Contingent Liabilities, Commitments and Legal Matters (Detail) - USD ($) $ in Thousands	6 Months Ended
	Jan. 31, 2021	Jul. 31, 2020
Commitments and Contingencies Disclosure [Abstract]
Standby repurchase obligations amount	$ 2,367,122	$ 1,876,922
Term of commitments	18 months
Repurchase and guarantee reserve balances	$ 8,054	$ 7,747