Loans - Summary of Loan Balances (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	$ 867,978	$ 861,241
Allowance for loan losses	(15,395)	(16,528)
Net loans	852,583	844,713
Commercial and Agriculture [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	107,769	115,875
Commercial Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	441,263	443,846
Residential Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	254,672	250,691
Real Estate Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	51,243	39,964
Consumer and Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Loans	$ 13,031	$ 10,865