Quarterly Results of Operations (Parenthetical) (Detail) (USD $)	3 Months Ended			12 Months Ended
	Jul. 31, 2014	Apr. 30, 2014	Jan. 31, 2014	Jul. 31, 2014
Effect of Fourth Quarter Events [Line Items]
Impact of retroactive accounting treatment of bargain purchase gain, total	$ 4,000,000	$ 1,400,000	$ 2,600,000
Bargain purchase gain recorded	$ 4,000,000	$ (1,400,000)	$ 8,621,000	$ 8,621,000