Loan and Lease Modifications Categorized as Troubled Debt Restructurings (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended	9 Months Ended
	Sep. 30, 2013 Contract	Sep. 30, 2013 Contract
Financing Receivable, Modifications [Line Items]
Number of Contracts	4	11
Pre-Modification Outstanding Recorded Investment	$ 126	$ 1,715
Post-Modification Outstanding Recorded Investment	126	1,715
Residential mortgage
Financing Receivable, Modifications [Line Items]
Number of Contracts		2
Pre-Modification Outstanding Recorded Investment		674
Post-Modification Outstanding Recorded Investment		674
Home equity lines and loans
Financing Receivable, Modifications [Line Items]
Number of Contracts		2
Pre-Modification Outstanding Recorded Investment		40
Post-Modification Outstanding Recorded Investment		40
Commercial and industrial
Financing Receivable, Modifications [Line Items]
Number of Contracts	1	2
Pre-Modification Outstanding Recorded Investment	75	930
Post-Modification Outstanding Recorded Investment	75	930
Leases
Financing Receivable, Modifications [Line Items]
Number of Contracts	2	4
Pre-Modification Outstanding Recorded Investment	18	38
Post-Modification Outstanding Recorded Investment	18	38
Consumer
Financing Receivable, Modifications [Line Items]
Number of Contracts	1	1
Pre-Modification Outstanding Recorded Investment	33	33
Post-Modification Outstanding Recorded Investment	$ 33	$ 33