Foreclosed Assets - Activity In Valuation Allowance (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning valuation allowance	$ 1,139	$ 1,139	$ 1,139
Additions charged to expense	780		962	1,139
Direct write-downs	(1,919)		(2,101)
Ending valuation allowance	$ 0	$ 1,139	$ 0	$ 1,139