Non-performing Assets and Impaired Loans - Commercial Loans Individually Evaluated for Impairment by Class of Loans (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Schedule Of Financial Receivables [Line Items]
Unpaid Principal Balance total	$ 7,313	$ 10,054
Total ending loans balance	7,335	10,078
Allowance For Loan Loss Allocated	1,290	1,945
Average Balance in Impaired Loans total	8,126	13,879
Cash/Accrual Interest Income Recognized, Total	19	25
Commercial [Member]
Schedule Of Financial Receivables [Line Items]
Unpaid Principal Balance With no recorded allowance	4,945	6,935
Recorded Investment With no recorded allowance	4,967	6,959
Allowance For Loan Loss Allocated With no recorded allowance
Average Balance in Impaired Loans With no recorded allowance	5,905	10,742
Cash/Accrual Interest Income Recognized, With no recorded allowance	17	25
Unpaid Principal Balance With an allowance recorded	2,368	3,119
Recorded Investment With an allowance recorded	2,368	3,119
Allowance For Loan Loss Allocated	1,290	1,945
Average Balance in Impaired Loans With an allowance recorded	2,221	3,137
Cash/Accrual Interest Income Recognized, With an allowance recorded	2
Commercial [Member] | Owner Occupied Real Estate [Member]
Schedule Of Financial Receivables [Line Items]
Unpaid Principal Balance With no recorded allowance	1,145	3,310
Recorded Investment With no recorded allowance	1,148	3,317
Allowance For Loan Loss Allocated With no recorded allowance
Average Balance in Impaired Loans With no recorded allowance	1,759	4,906
Cash/Accrual Interest Income Recognized, With no recorded allowance	12	14
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	(1)
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	3,443	2,578
Recorded Investment With no recorded allowance	3,446	2,579
Allowance For Loan Loss Allocated With no recorded allowance
Average Balance in Impaired Loans With no recorded allowance	3,514	3,793
Cash/Accrual Interest Income Recognized, With no recorded allowance	5	11
Unpaid Principal Balance With an allowance recorded	347	1,763
Recorded Investment With an allowance recorded	347	1,763
Allowance For Loan Loss Allocated	170	1,080
Average Balance in Impaired Loans With an allowance recorded	353	1,774
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
Recorded Investment With no recorded allowance
Allowance For Loan Loss Allocated With no recorded allowance
Average Balance in Impaired Loans With no recorded allowance
Cash/Accrual Interest Income Recognized, 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	24	135
Recorded Investment With no recorded allowance	24	135
Allowance For Loan Loss Allocated With no recorded allowance
Average Balance in Impaired Loans With no recorded allowance	24	166
Cash/Accrual Interest Income Recognized, With no recorded allowance
Unpaid Principal Balance With an allowance recorded	138	564
Recorded Investment With an allowance recorded	138	564
Allowance For Loan Loss Allocated	40	600
Average Balance in Impaired Loans With an allowance recorded	142	569
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	333	912
Recorded Investment With no recorded allowance	349	928
Allowance For Loan Loss Allocated With no recorded allowance
Average Balance in Impaired Loans With no recorded allowance	608	1,877
Cash/Accrual Interest Income Recognized, With no recorded allowance
Unpaid Principal Balance With an allowance recorded	1,883	792
Recorded Investment With an allowance recorded	1,883	792
Allowance For Loan Loss Allocated	1,080	265
Average Balance in Impaired Loans With an allowance recorded	1,727	794
Cash/Accrual Interest Income Recognized, With an allowance recorded	$ 2