Preferred Stock (Additional Information) (Detail) (USD $)	9 Months Ended	12 Months Ended			9 Months Ended
	Jun. 30, 2013	Sep. 30, 2011	Aug. 11, 2011	Jun. 30, 2013 First ten quarters	Jun. 30, 2013 First ten quarters Minimum	Jun. 30, 2013 First ten quarters Maximum	Jun. 30, 2013 After four and one half years from issuance	Jun. 30, 2013 Senior Non-Cumulative Perpetual Preferred Stock, Series A	Sep. 30, 2012 Senior Non-Cumulative Perpetual Preferred Stock, Series A
Auction Market Preferred Securities, Stock Series [Line Items]
Weighted Average Dividend Rate	1.00%				1.00%	7.00%
Preferred Stock, issued			17,120					17,120	17,120
Series A Preferred Stock, total purchase price under Purchase Agreement			$ 17,120,000					$ 17,120,000	$ 17,120,000
Annual lending incentive fee, percentage under Purchase Agreement				2.00%
Series A Preferred Stock, dividend rate under Purchase Agreement	1.00%	4.84%			1.00%	5.00%	9.00%
Series A Preferred Stock redemption price, under Purchase Agreement	100.00%
Preferred Stock, aggregate liquidation preference			$ 1,000
Tier One Risk Based Capital	10,000,000,000
Proceeds from Issuance of Common Stock	$ 30