Allowance for Loan Losses - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014 SecurityLoan	Jun. 30, 2013 SecurityLoan	Jun. 30, 2014 SecurityLoan	Jun. 30, 2013 SecurityLoan	Dec. 31, 2013
Accounts, Notes, Loans and Financing Receivable [Line Items]
Historical loss percentage period for portfolio segments			2 years
Adequate allowance for loan losses	$ 15,395		$ 15,395		$ 16,528
Number of days past due for loans to be considered as nonperforming			90 days
Reasonable period for nonperforming TDRs to be returned to performing status			6 months
Defaulted loans	0	2	0	2
Loans		66		66
Impaired loans			At or above $350,000
Due days for testing impairment			60 days
TDRs [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Adequate allowance for loan losses	$ 465		$ 465