Loans and Loans Held for Sale - Restructured Loans for Periods Stated (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014 SecurityLoan		Mar. 31, 2013 SecurityLoan
Financing Receivable, Modifications [Line Items]
Number of Loans	12		29
Pre-Modification Outstanding Recorded Investment	$ 1,808	[1]	$ 2,972	[1]
Post-Modification Outstanding Recorded Investment	1,791	[1]	2,584
Total Difference in Recorded Investment	(17)		(388)
Principal Deferral [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans	1		7
Pre-Modification Outstanding Recorded Investment	1,019	[1]	2,260	[1]
Post-Modification Outstanding Recorded Investment	1,019	[1]	1,873	[1]
Total Difference in Recorded Investment	0		(387)
Chapter 7 Bankruptcy [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans	11	[2]	22	[2]
Pre-Modification Outstanding Recorded Investment	789	[1],[2]	712	[1],[2]
Post-Modification Outstanding Recorded Investment	772	[1],[2]	711	[1],[2]
Total Difference in Recorded Investment	(17)	[2]	(1)	[2]
Commercial Real Estate [Member] | Principal Deferral [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans	0		3
Pre-Modification Outstanding Recorded Investment	0	[1]	1,541	[1]
Post-Modification Outstanding Recorded Investment	0	[1]	1,288	[1]
Total Difference in Recorded Investment	0		(253)
Commercial Real Estate [Member] | Chapter 7 Bankruptcy [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans	0	[2]	3	[2]
Pre-Modification Outstanding Recorded Investment	0	[1],[2]	205	[1],[2]
Post-Modification Outstanding Recorded Investment	0	[1],[2]	204	[1],[2]
Total Difference in Recorded Investment	0	[2]	(1)	[2]
Commercial and Industrial [Member] | Principal Deferral [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans	0		1
Pre-Modification Outstanding Recorded Investment	0	[1]	392	[1]
Post-Modification Outstanding Recorded Investment	0	[1]	387	[1]
Total Difference in Recorded Investment	0		(5)
Commercial and Industrial [Member] | Chapter 7 Bankruptcy [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans	1	[2]	1	[2]
Pre-Modification Outstanding Recorded Investment	287	[1],[2]	3	[1],[2]
Post-Modification Outstanding Recorded Investment	286	[1],[2]	3	[1],[2]
Total Difference in Recorded Investment	(1)	[2]	0	[2]
Commercial Construction [Member] | Principal Deferral [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans	1		0
Pre-Modification Outstanding Recorded Investment	1,019	[1]	0	[1]
Post-Modification Outstanding Recorded Investment	1,019	[1]	0	[1]
Total Difference in Recorded Investment	0		0
Residential Mortgage [Member] | Principal Deferral [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans	0		2
Pre-Modification Outstanding Recorded Investment	0	[1]	153	[1]
Post-Modification Outstanding Recorded Investment	0	[1]	153	[1]
Total Difference in Recorded Investment	0		0
Residential Mortgage [Member] | Chapter 7 Bankruptcy [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans	4	[2]	6	[2]
Pre-Modification Outstanding Recorded Investment	277	[1],[2]	269	[1],[2]
Post-Modification Outstanding Recorded Investment	276	[1],[2]	269	[1],[2]
Total Difference in Recorded Investment	(1)	[2]	0	[2]
Home Equity [Member] | Principal Deferral [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans	0		1
Pre-Modification Outstanding Recorded Investment	0	[1]	174	[1]
Post-Modification Outstanding Recorded Investment	0	[1]	45	[1]
Total Difference in Recorded Investment	0		(129)
Home Equity [Member] | Chapter 7 Bankruptcy [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans	6	[2]	6	[2]
Pre-Modification Outstanding Recorded Investment	225	[1],[2]	162	[1],[2]
Post-Modification Outstanding Recorded Investment	210	[1],[2]	162	[1],[2]
Total Difference in Recorded Investment	(15)	[2]	0	[2]
Installment and Other Consumer [Member] | Chapter 7 Bankruptcy [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans	0	[2]	6	[2]
Pre-Modification Outstanding Recorded Investment	0	[1],[2]	73	[1],[2]
Post-Modification Outstanding Recorded Investment	0	[1],[2]	73	[1],[2]
Total Difference in Recorded Investment	$ 0	[2]	$ 0	[2]

[1] Excludes loans that were fully paid off or fully charged-off by period end. The pre-modification balance represents the balance outstanding prior to modification. The post-modification balance represents the outstanding balance at period end.

[2] Chapter 7 bankruptcy loans where the debt has been legally discharged through the bankruptcy court and not reaffirmed.