Nonaccrual Loans by Loan Class (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Financing Receivable, Impaired [Line Items]
Total	$ 18,411	$ 22,506
Purchased impaired loans	8	8
Total nonaccrual loans	18,419	22,514
Commercial Loans \| Construction Development And Other Land
Financing Receivable, Impaired [Line Items]
Total	506	1,948
Commercial Loans \| Commercial and Industrial
Financing Receivable, Impaired [Line Items]
Total	5,022	5,433
Commercial Loans \| Multi-family Residential
Financing Receivable, Impaired [Line Items]
Total	197
Commercial Loans \| Single-family Non-owner Occupied
Financing Receivable, Impaired [Line Items]
Total	1,185	2,188
Commercial Loans \| Non-farm, Non-residential
Financing Receivable, Impaired [Line Items]
Total	3,024	2,685
Commercial Loans \| Farmland Loan
Financing Receivable, Impaired [Line Items]
Total	510	742
Consumer Real Estate \| Home Equity Lines
Financing Receivable, Impaired [Line Items]
Total	398	997
Consumer Real Estate \| Single Family Owner Occupied
Financing Receivable, Impaired [Line Items]
Total	7,378	8,122
Consumer Real Estate \| Owner occupied construction
Financing Receivable, Impaired [Line Items]
Total	115	190
Consumer and Other \| Consumer Loan
Financing Receivable, Impaired [Line Items]
Total	76	201
Non Covered Loans
Financing Receivable, Impaired [Line Items]
Total	17,456	19,153
Purchased impaired loans	8	8
Total nonaccrual loans	17,464	19,161
Non Covered Loans \| Commercial Loans \| Construction Development And Other Land
Financing Receivable, Impaired [Line Items]
Total	346	1,187
Non Covered Loans \| Commercial Loans \| Commercial and Industrial
Financing Receivable, Impaired [Line Items]
Total	5,022	5,341
Non Covered Loans \| Commercial Loans \| Multi-family Residential
Financing Receivable, Impaired [Line Items]
Total	197
Non Covered Loans \| Commercial Loans \| Single-family Non-owner Occupied
Financing Receivable, Impaired [Line Items]
Total	1,071	1,966
Non Covered Loans \| Commercial Loans \| Non-farm, Non-residential
Financing Receivable, Impaired [Line Items]
Total	2,951	2,685
Non Covered Loans \| Commercial Loans \| Farmland Loan
Financing Receivable, Impaired [Line Items]
Total	510	441
Non Covered Loans \| Consumer Real Estate \| Home Equity Lines
Financing Receivable, Impaired [Line Items]
Total	328	765
Non Covered Loans \| Consumer Real Estate \| Single Family Owner Occupied
Financing Receivable, Impaired [Line Items]
Total	6,955	6,567
Non Covered Loans \| Consumer and Other \| Consumer Loan
Financing Receivable, Impaired [Line Items]
Total	76	201
Covered Loans
Financing Receivable, Impaired [Line Items]
Total	955	3,353
Total nonaccrual loans	955	3,353
Covered Loans \| Commercial Loans \| Construction Development And Other Land
Financing Receivable, Impaired [Line Items]
Total	160	761
Covered Loans \| Commercial Loans \| Commercial and Industrial
Financing Receivable, Impaired [Line Items]
Total		92
Covered Loans \| Commercial Loans \| Single-family Non-owner Occupied
Financing Receivable, Impaired [Line Items]
Total	114	222
Covered Loans \| Commercial Loans \| Non-farm, Non-residential
Financing Receivable, Impaired [Line Items]
Total	73
Covered Loans \| Commercial Loans \| Farmland Loan
Financing Receivable, Impaired [Line Items]
Total		301
Covered Loans \| Consumer Real Estate \| Home Equity Lines
Financing Receivable, Impaired [Line Items]
Total	70	232
Covered Loans \| Consumer Real Estate \| Single Family Owner Occupied
Financing Receivable, Impaired [Line Items]
Total	423	1,555
Covered Loans \| Consumer Real Estate \| Owner occupied construction
Financing Receivable, Impaired [Line Items]
Total	$ 115	$ 190