Aging of Recorded Investment in Past Due Loans (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due	$ 5,667	$ 10,696
60 - 89 Days Past Due	1,232	775
90 Days And Over Past Due		232
Nonaccrual	77,344	101,767
Total Past Due And Nonaccrual	84,243	113,470
Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due	320	156
60 - 89 Days Past Due	49	123
Nonaccrual	2,735	2,886
Total Past Due And Nonaccrual	3,104	3,165
Commercial Real Estate | Construction
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due		261
Nonaccrual	7,169	8,528
Total Past Due And Nonaccrual	7,169	8,789
Commercial Real Estate | Farmland
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due	347	484
60 - 89 Days Past Due	208	41
Nonaccrual	6,755	7,844
Total Past Due And Nonaccrual	7,310	8,369
Commercial Real Estate | Nonfarm nonresidential
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due	2,217	4,375
60 - 89 Days Past Due	347
Nonaccrual	44,771	48,447
Total Past Due And Nonaccrual	47,335	52,822
Residential Real Estate | Multi-Family
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due		1,181
Nonaccrual	558	7,513
Total Past Due And Nonaccrual	558	8,694
Residential Real Estate | 1-4 Family
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due	2,523	4,059
60 - 89 Days Past Due	505	577
90 Days And Over Past Due		230
Nonaccrual	14,872	26,098
Total Past Due And Nonaccrual	17,900	30,964
Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due	142	145
60 - 89 Days Past Due	52	34
90 Days And Over Past Due		2
Nonaccrual		9
Total Past Due And Nonaccrual	194	190
Agriculture
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due	118	35
60 - 89 Days Past Due	71
Nonaccrual	299	322
Total Past Due And Nonaccrual	488	357
Other
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual	185	120
Total Past Due And Nonaccrual	$ 185	$ 120