Contractual Amount of Financial Instruments with Off-Balance-Sheet Risk (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Commitments to extend credit
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Contract amount, fixed rate	$ 48,139	$ 35,425
Contract amount, variable rate	56,628	61,613
Unused lines of credit
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Contract amount, fixed rate	958	3,403
Contract amount, variable rate	327,599	268,669
Standby letters of credit
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Contract amount, fixed rate	10	10
Contract amount, variable rate	$ 6,339	$ 6,289