Loans - Schedule of Loans Not Rated by Class of Loans (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Financing Receivable, Recorded Investment [Line Items]
Loans not rated by class of loans	$ 129,610	$ 121,662
Performing [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans not rated by class of loans	128,437	120,620
Non-Performing [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans not rated by class of loans	1,173	1,042
Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans not rated by class of loans	1,915	865
Commercial [Member] | Performing [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans not rated by class of loans	1,915	865
Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans not rated by class of loans	802	1,446
Commercial Real Estate [Member] | Performing [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans not rated by class of loans	802	1,446
Residential Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans not rated by class of loans	118,274	111,161
Residential Real Estate [Member] | Performing [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans not rated by class of loans	117,101	110,119
Residential Real Estate [Member] | Non-Performing [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans not rated by class of loans	1,173	1,042
Construction & Land Development [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans not rated by class of loans	1,228	1,503
Construction & Land Development [Member] | Performing [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans not rated by class of loans	1,228	1,503
Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans not rated by class of loans	7,391	6,687
Consumer [Member] | Performing [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans not rated by class of loans	$ 7,391	$ 6,687