Subsequent Events - Additional Information (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	0 Months Ended				1 Months Ended
	Dec. 22, 2010	Dec. 15, 2009	Jul. 31, 2012	Jul. 31, 2011	Sep. 30, 2012 Fiscal Year 2013	Sep. 19, 2012 Fiscal Year 2013
Subsequent Event [Line Items]
Special cash distribution per share of common stock	$ 6.50	$ 1.00			$ 10.00
Par value of common stock	$ 0.001	$ 0.001	$ 0.001	$ 0.001		$ 0.001
Common Stock			$ 29	$ 29		$ 288,800