Loans and Allowance for Loan Losses - Allowance Related to Loans Categorized as Troubled Debt Restructurings (Detail) (USD $)	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Schedule Of Financing Receivable Troubled Debt Restructurings [Line Items]
Total	$ 22,821,000	$ 28,677,000	$ 36,532,000	$ 45,368,000
Commercial Loans [Member]
Schedule Of Financing Receivable Troubled Debt Restructurings [Line Items]
Total	20,455,000	26,043,000	33,431,000	42,359,000
Retail Loans [Member]
Schedule Of Financing Receivable Troubled Debt Restructurings [Line Items]
Total	2,358,000	2,645,000	3,019,000	2,972,000
Financing Receivable Troubled Debt Restructuring [Member]
Schedule Of Financing Receivable Troubled Debt Restructurings [Line Items]
Total	10,351,000	13,097,000
Financing Receivable Troubled Debt Restructuring [Member] | Commercial and Industrial [Member]
Schedule Of Financing Receivable Troubled Debt Restructurings [Line Items]
Total	187,000	772,000
Financing Receivable Troubled Debt Restructuring [Member] | Commercial Vacant Land, Land Development, and Residential Construction [Member]
Schedule Of Financing Receivable Troubled Debt Restructurings [Line Items]
Total	798,000	713,000
Financing Receivable Troubled Debt Restructuring [Member] | Commercial Real Estate - Owner Occupied [Member]
Schedule Of Financing Receivable Troubled Debt Restructurings [Line Items]
Total	528,000	1,116,000
Financing Receivable Troubled Debt Restructuring [Member] | Commercial Real Estate - Non-Owner Occupied [Member]
Schedule Of Financing Receivable Troubled Debt Restructurings [Line Items]
Total	7,828,000	9,751,000
Financing Receivable Troubled Debt Restructuring [Member] | Commercial Real Estate - Multi-Family and Residential Rental [Member]
Schedule Of Financing Receivable Troubled Debt Restructurings [Line Items]
Total	1,010,000	745,000
Financing Receivable Troubled Debt Restructuring [Member] | Commercial Loans [Member]
Schedule Of Financing Receivable Troubled Debt Restructurings [Line Items]
Total	10,351,000	13,097,000
Financing Receivable Troubled Debt Restructuring [Member] | Home equity and other [Member]
Schedule Of Financing Receivable Troubled Debt Restructurings [Line Items]
Total	0	0
Financing Receivable Troubled Debt Restructuring [Member] | 1 - 4 family mortgages [Member]
Schedule Of Financing Receivable Troubled Debt Restructurings [Line Items]
Total	0	0
Financing Receivable Troubled Debt Restructuring [Member] | Retail Loans [Member]
Schedule Of Financing Receivable Troubled Debt Restructurings [Line Items]
Total	$ 0	$ 0