Loans and Allowance for Loan and Lease Losses - Loans Accounted for on Non Accrual Basis (Detail) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total	$ 4,427	$ 4,376
Commercial Real Estate Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total	812	812
Residential Real Estate Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total	2,344	2,212
Construction Real Estate Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total	836	836
Commercial Loans and Leases [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total	$ 435	$ 516