Schedule of Change in Retained Earnings (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jan. 31, 2014	Jan. 31, 2013	Jan. 31, 2014	Jan. 31, 2013
Retained Earnings Adjustments [Line Items]
Beginning Balance			$ 953,740
Net income	16,192	19,896	57,300	50,884
Dividends paid			(77,800)
Ending Balance	$ 933,240		$ 933,240