Non-performing Assets and Impaired Loans - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013 Contract ConsecutivePayment	Dec. 31, 2012
Financing Receivable, Modifications [Line Items]
Non-accrual loans	$ 9,748,000	$ 13,374,000
Non-performing TDR's	3,400,000
Loans acquired included in non-accrual loans	3,500,000
Loans acquired included in non-performing TDR's	1,200,000
Loan delinquency period	90 days
Minimum period required for satisfactory performance to return loan from non-accrual to accrual status	6 months
Restructured loans with modified recorded balances	0
Restructured loan returned to accruing status number of Consecutive Payments of loan	6
Restructured loan reported in TDRs	8,500,000
Specific reserves allocated to troubled debt restructuring	1,100,000
Number TDR's returned to accrual status	2
Total balances of TDR's	850,000
Loans with an aggregate credit exposure	500,000
Loans classified as TDR after a period	90 days
Good Pass [Member]
Financing Receivable, Modifications [Line Items]
Number of consecutive years of profit Unaudited Financial Information for Good Pass Rating	5 years
Number of years of Satisfactory Relationship with bank for Good Pass Rating	5 years
Performing Financing Receivable [Member]
Financing Receivable, Modifications [Line Items]
Restructured loan	$ 5,100,000
Minimum [Member]
Financing Receivable, Modifications [Line Items]
Delay or shortfall in payments of loan	30 days
Period for loans moved to non-accrual status	90 days
Minimum [Member] | Good Pass [Member]
Financing Receivable, Modifications [Line Items]
Number of consecutive years of profit for Good Pass Rating	3 years
Minimum [Member] | Satisfactory Pass [Member]
Financing Receivable, Modifications [Line Items]
Minimum number of years of Satisfactory Repayment required for Satisfactory Pass Rating	2 years