Information in Regard to Troubled Debt Restructurings that Occurred During Period (Detail) (Troubled Debt Restructuring, USD $) In Thousands, unless otherwise specified	3 Months Ended	6 Months Ended
	Jun. 30, 2013 Contract	Jun. 30, 2013 Contract	Jun. 30, 2012 Contract
Financing Receivable, Modifications [Line Items]
Number of Contracts	1	1	2
Pre-Modification Outstanding Balance	$ 160	$ 160	$ 113
Post-Modification Outstanding Balance	160	160	112
Residential
Financing Receivable, Modifications [Line Items]
Number of Contracts	1	1	1
Pre-Modification Outstanding Balance	160	160	88
Post-Modification Outstanding Balance	160	160	87
Home Equity and Second Mortgage
Financing Receivable, Modifications [Line Items]
Number of Contracts	0	0	1
Pre-Modification Outstanding Balance	0	0	25
Post-Modification Outstanding Balance	0	0	25
Construction
Financing Receivable, Modifications [Line Items]
Number of Contracts	0	0	0
Pre-Modification Outstanding Balance	0	0	0
Post-Modification Outstanding Balance	0	0	0
Commercial Real Estate
Financing Receivable, Modifications [Line Items]
Number of Contracts	0	0	0
Pre-Modification Outstanding Balance	0	0	0
Post-Modification Outstanding Balance	0	0	0
Commercial Business
Financing Receivable, Modifications [Line Items]
Number of Contracts	0	0	0
Pre-Modification Outstanding Balance	0	0	0
Post-Modification Outstanding Balance	0	0	0
Other Consumer
Financing Receivable, Modifications [Line Items]
Number of Contracts	0	0	0
Pre-Modification Outstanding Balance	0	0	0
Post-Modification Outstanding Balance	$ 0	$ 0	$ 0