Summary of Organization - Additional Information (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014	Dec. 31, 2013
Organization [Line Items]
Date of entity incorporation	Jun. 23, 1995
Entity Incorporation, State Country Name	Hattiesburg, Mississippi
Assets	$ 1,146,148		$ 1,093,768
Loans, including Loans held for sale	718,016		706,634
Deposits	984,643		892,775
Stockholders' equity	98,766	87,496	96,216	85,108
Net income	2,029	1,427
Net income applicable to common Stockholders	$ 1,944	$ 1,321
Dividends on common stock, per share	$ 0.0375	$ 0.0375