Loans - Summary of Troubled Debt Restructurings (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013 Contract	Sep. 30, 2012 Contract	Sep. 30, 2013 Contract	Sep. 30, 2012 Contract
Financing Receivable, Modifications [Line Items]
Number of loans restructured	3	6	5	8
Pre-Modification Recorded Investment	$ 195	$ 473	$ 271	$ 628
Post-Modification Recorded Investment	195	473	271	628
Commercial [Member]
Financing Receivable, Modifications [Line Items]
Number of loans restructured	1		3
Pre-Modification Recorded Investment	7		83
Post-Modification Recorded Investment	7		83
Residential Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Number of loans restructured	2	5	2	7
Pre-Modification Recorded Investment	188	333	188	488
Post-Modification Recorded Investment	188	333	188	488
Commercial Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Number of loans restructured		1		1
Pre-Modification Recorded Investment		140		140
Post-Modification Recorded Investment		$ 140		$ 140