Loans and Allowance for Loan Losses - Schedule of Troubled Debt Restructurings (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014 Contract	Dec. 31, 2013 Contract
Financing Receivable, Recorded Investment, Past Due [Line Items]
Number	1	8
Balance	$ 32	$ 334
Commercial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Number		6
Balance		316
Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Number	1	2
Balance	$ 32	$ 18