Breakdown of Non-accrual Loans (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Non-accrual loans	$ 4,619	$ 3,078
Commercial & Industrial Loans
Non-accrual loans	1,408	1,237
Commercial & Industrial Loans | Other
Non-accrual loans	1,408	1,237
Construction & Development
Non-accrual loans	409	740
Construction & Development | Other
Non-accrual loans	409	740
Construction Loans
Non-accrual loans	2,802	1,101
Construction Loans | Other
Non-accrual loans	1,701
Construction Loans | Owner Occupied
Non-accrual loans	$ 1,101	$ 1,101