Non-performing Loans and Impaired Loans - Commercial Loans Individually Evaluated for Impairment by Class of Loans (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Schedule Of Financial Receivables [Line Items]
Unpaid Principal Balance total	$ 7,710	$ 9,390	$ 7,710	$ 9,390
Total ending loans balance	7,715	9,427	7,715	9,427
Allowance For Loan Loss Allocated	1,135	2,398	1,135	2,398
Average Balance in Impaired Loans total	7,648	10,908	7,098	9,917
Cash/Accrual Interest Income Recognized, Total	133	48	151	73
Commercial [Member]
Schedule Of Financial Receivables [Line Items]
Unpaid Principal Balance With no recorded allowance	5,648	4,687	5,648	4,687
Recorded Investment With no recorded allowance	5,653	4,712	5,653	4,712
Allowance For Loan Loss Allocated With no recorded allowance
Average Balance in Impaired Loans With no recorded allowance	5,596	6,119	5,181	5,747
Cash/Accrual Interest Income Recognized, With no recorded allowance	133	28	149	53
Unpaid Principal Balance With an allowance recorded	2,062	4,703	2,062	4,703
Recorded Investment With an allowance recorded	2,062	4,715	2,062	4,715
Allowance For Loan Loss Allocated	1,135	2,398	1,135	2,398
Average Balance in Impaired Loans With an allowance recorded	2,052	4,789	1,917	4,170
Cash/Accrual Interest Income Recognized, With an allowance recorded		20	2	20
Commercial [Member] | Owner Occupied Real Estate [Member]
Schedule Of Financial Receivables [Line Items]
Unpaid Principal Balance With no recorded allowance	2,121	1,142	2,121	1,142
Recorded Investment With no recorded allowance	2,124	1,146	2,124	1,146
Allowance For Loan Loss Allocated With no recorded allowance
Average Balance in Impaired Loans With no recorded allowance	1,885	1,750	1,432	1,785
Cash/Accrual Interest Income Recognized, With no recorded allowance	40	13	51	27
Unpaid Principal Balance With an allowance recorded		172		172
Recorded Investment With an allowance recorded		172		172
Allowance For Loan Loss Allocated		30		30
Average Balance in Impaired Loans With an allowance recorded		216		222
Cash/Accrual Interest Income Recognized, With an allowance recorded
Commercial [Member] | Non-owner Occupied Real Estate [Member]
Schedule Of Financial Receivables [Line Items]
Unpaid Principal Balance With no recorded allowance	3,244	2,579	3,244	2,579
Recorded Investment With no recorded allowance	3,246	2,584	3,246	2,584
Allowance For Loan Loss Allocated With no recorded allowance
Average Balance in Impaired Loans With no recorded allowance	3,270	2,710	3,283	2,439
Cash/Accrual Interest Income Recognized, With no recorded allowance	93	12	98	23
Unpaid Principal Balance With an allowance recorded	340	1,795	340	1,795
Recorded Investment With an allowance recorded	340	1,795	340	1,795
Allowance For Loan Loss Allocated	170	1,097	170	1,097
Average Balance in Impaired Loans With an allowance recorded	342	1,799	347	1,809
Cash/Accrual Interest Income Recognized, With an allowance recorded
Commercial [Member] | Residential Development [Member]
Schedule Of Financial Receivables [Line Items]
Unpaid Principal Balance With no recorded allowance
Unpaid Principal Balance With an allowance recorded
Recorded Investment With an allowance recorded
Allowance For Loan Loss Allocated
Average Balance in Impaired Loans With an allowance recorded
Cash/Accrual Interest Income Recognized, With an allowance recorded
Commercial [Member] | Development & Spec Land Loans [Member]
Schedule Of Financial Receivables [Line Items]
Unpaid Principal Balance With no recorded allowance		60		60
Recorded Investment With no recorded allowance		60		60
Allowance For Loan Loss Allocated With no recorded allowance
Average Balance in Impaired Loans With no recorded allowance		64		45
Cash/Accrual Interest Income Recognized, With no recorded allowance
Unpaid Principal Balance With an allowance recorded		673		673
Recorded Investment With an allowance recorded		673		673
Allowance For Loan Loss Allocated		425		425
Average Balance in Impaired Loans With an allowance recorded		702		706
Cash/Accrual Interest Income Recognized, With an allowance recorded
Commercial [Member] | Commercial and Industrial [Member]
Schedule Of Financial Receivables [Line Items]
Unpaid Principal Balance With no recorded allowance	283	906	283	906
Recorded Investment With no recorded allowance	283	922	283	922
Allowance For Loan Loss Allocated With no recorded allowance
Average Balance in Impaired Loans With no recorded allowance	441	1,595	466	1,478
Cash/Accrual Interest Income Recognized, With no recorded allowance		3		3
Unpaid Principal Balance With an allowance recorded	1,722	2,063	1,722	2,063
Recorded Investment With an allowance recorded	1,722	2,075	1,722	2,075
Allowance For Loan Loss Allocated	965	846	965	846
Average Balance in Impaired Loans With an allowance recorded	1,710	2,072	1,570	1,433
Cash/Accrual Interest Income Recognized, With an allowance recorded		$ 20	$ 2	$ 20