Contingent Liabilities Commitments and Legal Matters - Additional Information (Detail) - USD ($) $ in Thousands	6 Months Ended
	Jan. 31, 2016	Jul. 31, 2015
Loss Contingencies [Line Items]
Standby Repurchase Obligations Amount	$ 1,558,560	$ 1,363,576
Term of Commitments	Up to eighteen months
Repurchase and guarantee reserve balances	$ 4,650	$ 4,163