Fair Value of Financial Instruments - Schedule of Estimated Fair Values of Banks Financial Instruments (Detail) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Securities	$ 207,528	$ 210,857
Other Equity Securities	6,181	5,350
Carrying Amount [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and Short-Term Investments	116,768	43,407
Securities	207,528	210,857
Loans - Net	790,470	765,148
Cash Value of BOLI	22,269	22,339
Other Equity Securities	6,181	5,350
Total Assets	1,143,216	1,047,101
Deposits	998,658	904,236
Borrowings	53,650	54,579
Total Liabilities	1,052,308	958,815
Fair Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and Short-Term Investments	116,768	43,407
Securities	207,528	210,857
Loans - Net	787,596	761,241
Cash Value of BOLI	22,269	22,339
Other Equity Securities	6,181	5,350
Total Assets	1,140,342	1,043,194
Deposits	984,769	897,771
Borrowings	53,634	54,561
Total Liabilities	1,038,403	952,332
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and Short-Term Investments	116,768	43,407
Total Assets	116,768	43,407
Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Securities	207,528	210,857
Cash Value of BOLI	22,269	22,339
Total Assets	229,797	233,196
Borrowings	53,634	54,561
Total Liabilities	53,634	54,561
Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans - Net	787,596	761,241
Other Equity Securities	6,181	5,350
Total Assets	793,777	766,591
Deposits	984,769	897,771
Total Liabilities	$ 984,769	$ 897,771