Federal Home Loan Bank Advances - Additional Information (Detail) (Federal Home Loan Bank Of Atlanta, USD $) In Millions, unless otherwise specified	Sep. 30, 2012
Federal Home Loan Bank, Advances, Branch of FHLB Bank [Line Items]
Credit availability as a percent of quarter-end assets	20.00%
Remaining credit available with FHLB	$ 53.7
Qualifying Home Equity Lines of Credit
Federal Home Loan Bank, Advances, Branch of FHLB Bank [Line Items]
Maximum borrowing capacity from FHLB	31.1
Commercial Real Estate
Federal Home Loan Bank, Advances, Branch of FHLB Bank [Line Items]
Maximum borrowing capacity from FHLB	100.9
Qualifying Multifamily Real Estate Loans
Federal Home Loan Bank, Advances, Branch of FHLB Bank [Line Items]
Maximum borrowing capacity from FHLB	9.6
Qualifying Residential Real Estate Secured Loans
Federal Home Loan Bank, Advances, Branch of FHLB Bank [Line Items]
Maximum borrowing capacity from FHLB	$ 16.7