Contingent Liabilities Commitments and Legal Matters - Additional Information (Detail) - USD ($) $ in Thousands	9 Months Ended
	Apr. 30, 2016	Jul. 31, 2015
Loss Contingencies [Line Items]
Standby Repurchase Obligations Amount	$ 1,629,562	$ 1,363,576
Term of Commitments	Up to eighteen months
Repurchase and guarantee reserve balances	$ 5,177	$ 4,163