Age Analysis of Composition of Past Due Loans and Non-Accrual Loans by Class of Loans (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due	$ 1,880	$ 5,158
60-89 Days Past Due	1,559	4,005
Non-Accrual	4,619	3,078
Total Past Due	8,058	12,241
Current Loans	454,486	408,395
Total Loans	462,544	420,636
Commercial & Industrial Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due	62	226
60-89 Days Past Due		242
Non-Accrual	1,408	1,237
Total Past Due	1,470	1,705
Current Loans	92,423	93,171
Total Loans	93,893	94,876
Construction & Development
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due		819
Non-Accrual	409	740
Total Past Due	409	1,559
Current Loans	66,300	49,519
Total Loans	66,709	51,078
Commercial Real Estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due	1,648	3,152
60-89 Days Past Due		3,763
Non-Accrual	2,802	1,101
Total Past Due	4,450	8,016
Current Loans	245,710	223,803
Total Loans	250,160	231,819
Residential Real Estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due	151	961
60-89 Days Past Due	1,559
Total Past Due	1,710	961
Current Loans	48,131	39,865
Total Loans	49,841	40,826
Consumer Loan
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due	19
Total Past Due	19
Current Loans	1,922	2,037
Total Loans	$ 1,941	$ 2,037