Average Recorded Investment and Interest Income Recognized on Impaired Loans Excluding Purchased Credit Impaired Loans (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2014	Mar. 31, 2013
Financing Receivable, Recorded Investment [Line Items]
Impaired loans with no related allowance, Average Recorded Investment	$ 9,359	$ 10,558
Impaired loans with a related allowance, Average Recorded Investment	20,340	15,454
Total impaired loans, Average Recorded Investment	29,699	26,012
Impaired loans with no related allowance, Interest Income Recognized	113	451
Impaired loans with a related allowance, Interest Income Recognized	130	193
Total impaired loans, Interest Income Recognized	243	644
Commercial Loans \| Construction Development And Other Land
Financing Receivable, Recorded Investment [Line Items]
Impaired loans with no related allowance, Average Recorded Investment		2,195
Impaired loans with a related allowance, Average Recorded Investment		2,670
Impaired loans with no related allowance, Interest Income Recognized		43
Impaired loans with a related allowance, Interest Income Recognized		117
Commercial Loans \| Commercial and Industrial
Financing Receivable, Recorded Investment [Line Items]
Impaired loans with no related allowance, Average Recorded Investment	292	599
Impaired loans with a related allowance, Average Recorded Investment	5,157	3,217
Impaired loans with no related allowance, Interest Income Recognized	12	11
Impaired loans with a related allowance, Interest Income Recognized	47
Commercial Loans \| Multi-family Residential
Financing Receivable, Recorded Investment [Line Items]
Impaired loans with no related allowance, Average Recorded Investment		35
Impaired loans with a related allowance, Average Recorded Investment	5,603	376
Impaired loans with no related allowance, Interest Income Recognized		2
Impaired loans with a related allowance, Interest Income Recognized	22	7
Commercial Loans \| Single-family Non-owner Occupied
Financing Receivable, Recorded Investment [Line Items]
Impaired loans with no related allowance, Average Recorded Investment	420	841
Impaired loans with a related allowance, Average Recorded Investment	372	1,728
Impaired loans with no related allowance, Interest Income Recognized	1	79
Impaired loans with a related allowance, Interest Income Recognized	1	3
Commercial Loans \| Non-farm, Non-residential
Financing Receivable, Recorded Investment [Line Items]
Impaired loans with no related allowance, Average Recorded Investment	5,918	5,955
Impaired loans with a related allowance, Average Recorded Investment	4,399	2,756
Impaired loans with no related allowance, Interest Income Recognized	36	212
Impaired loans with a related allowance, Interest Income Recognized	25	26
Commercial Loans \| Farmland Loan
Financing Receivable, Recorded Investment [Line Items]
Impaired loans with no related allowance, Average Recorded Investment	363	88
Impaired loans with no related allowance, Interest Income Recognized	11	9
Consumer Real Estate \| Home Equity Lines
Financing Receivable, Recorded Investment [Line Items]
Impaired loans with no related allowance, Average Recorded Investment	265	298
Impaired loans with a related allowance, Average Recorded Investment	229	222
Impaired loans with no related allowance, Interest Income Recognized	2	25
Impaired loans with a related allowance, Interest Income Recognized	1	3
Consumer Real Estate \| Single Family Owner Occupied
Financing Receivable, Recorded Investment [Line Items]
Impaired loans with no related allowance, Average Recorded Investment	2,101	547
Impaired loans with a related allowance, Average Recorded Investment	4,580	4,485
Impaired loans with no related allowance, Interest Income Recognized	51	70
Impaired loans with a related allowance, Interest Income Recognized	$ 34	$ 37

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Average amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 15

-Subparagraph (c)(1)

-URI http://asc.fasb.org/extlink&oid=28368275&loc=d3e5212-111524

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 17

-URI http://asc.fasb.org/extlink&oid=28368275&loc=d3e5258-111524

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Amount of interest income recognized that the financing receivables (with related allowance for credit losses and without a related allowance for credit losses) were impaired.

+ References

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Amount of interest income, recognized on accrual basis, on financing receivables that are recognized as impaired, for which there is no related allowance for credit losses.

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Amount of interest income, recognized on accrual basis, on financing receivables, for which there is a related allowance for credit losses and are recognized as impaired.

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