Allowance for Loan Losses and Credit Quality Information - Schedule of Loans Identified as Troubled Debt Restructurings During Periods Indicated (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Financing Receivable, Modifications [Line Items]
Loans identified during the period	$ 642	$ 709
Commercial [Member]
Financing Receivable, Modifications [Line Items]
Loans identified during the period
Commercial Mortgages [Member]
Financing Receivable, Modifications [Line Items]
Loans identified during the period		235
Construction [Member]
Financing Receivable, Modifications [Line Items]
Loans identified during the period
Residential [Member]
Financing Receivable, Modifications [Line Items]
Loans identified during the period	279
Consumer [Member]
Financing Receivable, Modifications [Line Items]
Loans identified during the period	$ 363	$ 474