Shareholders' Equity, Dividend Restrictions and Other Regulatory Matters (Detail) (USD $)	9 Months Ended			12 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2009	Dec. 31, 2012	Mar. 29, 2012	Dec. 31, 2011	Sep. 29, 2009	Dec. 05, 2008
Issuance of stock for TARP repayment (in Dollars)								$ 65,000,000
Preferred Stock, Shares Issued (in Shares)	65,000			65,000		65,000		65,000
Class of Warrant or Right, Unissued (in Shares)							241,696	483,391
Preferred Stock, Par or Stated Value Per Share (in Dollars per share)	$ 0.01			$ 0.01	$ 873.51	$ 0.01		$ 0.01
Preferred Stock, Liquidation Preference Per Share (in Dollars per share)								$ 1,000
Preferred Stock, Dividend Rate, Percentage				4.85%
Class of Warrant or Right, Exercise Price of Warrants or Rights (in Dollars per Item)								20.17
Fair Value Assumptions, Expected Volatility Rate				35.40%
Fair Value Assumptions, Risk Free Interest Rate				2.50%
Preferred Stock, Value, Issued (in Dollars)	1,000			1,000	65,000,000	1,000
Investment Warrants Expiration Date				Dec. 31, 2008
Dividends Payable, Amount Per Share (in Dollars per share)					$ 12.50
Common Stock, Dividends Per Share, Cash Paid, Statutory Maximum (in Dollars per share)				$ 0.05
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount (in Shares)	743,333	962,547	646,083
Ratio of Indebtedness to Net Capital				0.0997		0.0900
Cash Reserve Deposit Required and Made (in Dollars)	5,000,000
Five Years Or Less [Member]
Preferred Stock, Dividend Rate, Percentage				5.00%
After Five Years [Member]
Preferred Stock, Dividend Rate, Percentage				9.00%
Series A Preferred Stock [Member]
Preferred Stock, Value, Issued (in Dollars)				$ 65,000,000