Loans Receivable - Recorded Investment and Unpaid Principal Balances for Impaired Loans Receivable (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Schedule Of Financial Receivables [Line Items]
Recorded Investment	$ 17,289	$ 15,904
Unpaid Principal Balance	17,562	16,174
Related Allowance	1,112	1,164
Commercial Real Estate [Member]
Schedule Of Financial Receivables [Line Items]
Recorded Investment	14,688	13,414
Unpaid Principal Balance	14,958	13,684
Related Allowance	1,063	1,110
Residential Real Estate, Single Family [Member]
Schedule Of Financial Receivables [Line Items]
Recorded Investment	1,357	1,360
Unpaid Principal Balance	1,357	1,360
Related Allowance
Residential Construction Loans [Member]
Schedule Of Financial Receivables [Line Items]
Recorded Investment	850	803
Unpaid Principal Balance	850	803
Related Allowance
Consumer [Member]
Schedule Of Financial Receivables [Line Items]
Recorded Investment	394	327
Unpaid Principal Balance	397	327
Related Allowance	49	54
With No Related Allowance Recorded [Member] | Commercial Real Estate [Member]
Schedule Of Financial Receivables [Line Items]
Recorded Investment	5,532	5,433
Unpaid Principal Balance	5,639	5,540
Related Allowance
With No Related Allowance Recorded [Member] | Residential Real Estate, Single Family [Member]
Schedule Of Financial Receivables [Line Items]
Recorded Investment	1,357	1,360
Unpaid Principal Balance	1,357	1,360
Related Allowance
With No Related Allowance Recorded [Member] | Residential Construction Loans [Member]
Schedule Of Financial Receivables [Line Items]
Recorded Investment	850	803
Unpaid Principal Balance	850	803
Related Allowance
With No Related Allowance Recorded [Member] | Consumer Home Equity [Member]
Schedule Of Financial Receivables [Line Items]
Recorded Investment	211	130
Unpaid Principal Balance	236	130
Related Allowance
With No Related Allowance Recorded [Member] | Dealer Auto and RV Loans [Member]
Schedule Of Financial Receivables [Line Items]
Recorded Investment	8	14
Unpaid Principal Balance	8	14
Related Allowance
With an Allowance Recorded [Member] | Commercial Real Estate [Member]
Schedule Of Financial Receivables [Line Items]
Recorded Investment	9,156	7,981
Unpaid Principal Balance	9,319	8,144
Related Allowance	1,063	1,110
With an Allowance Recorded [Member] | Consumer Home Equity [Member]
Schedule Of Financial Receivables [Line Items]
Recorded Investment	172	179
Unpaid Principal Balance	150	179
Related Allowance	46	50
With an Allowance Recorded [Member] | Dealer Auto and RV Loans [Member]
Schedule Of Financial Receivables [Line Items]
Recorded Investment	3	4
Unpaid Principal Balance	3	4
Related Allowance	$ 3	$ 4