Loans and Allowance for Loan Losses - Schedule of Average Net Investment Impaired Loans and Interest Income Recognized and Received on Impaired Loans (Detail) (USD $) In Thousands, unless otherwise specified	9 Months Ended	12 Months Ended
	Sep. 30, 2014	Dec. 31, 2013
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	$ 16,018	$ 42,501
Interest Income Recognized	428	1,573
Interest Income Received	423	1,601
Construction, Land Development and Other Land Loans [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	3,010	10,249
Interest Income Recognized	33	177
Interest Income Received	35	179
Secured by 1-4 Family Residential Properties [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	159	303
Interest Income Recognized	3	7
Interest Income Received	3	7
Secured by Multi-family Residential Properties [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	3,875	8,690
Interest Income Recognized	131	438
Interest Income Received	128	446
Secured by Non-farm, Non-residential Properties [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	8,867	22,272
Interest Income Recognized	260	918
Interest Income Received	256	935
Commercial and Industrial Loans [Member]
Financing Receivable, Impaired [Line Items]
Average Recorded Investment	107	987
Interest Income Recognized	1	33
Interest Income Received	$ 1	$ 34