Loans and Loans Held for Sale - Restructured Loans for Periods Stated (Detail) (USD $)	3 Months Ended				9 Months Ended
	Sep. 30, 2014 SecurityLoan		Sep. 30, 2013 SecurityLoan		Sep. 30, 2014 SecurityLoan		Sep. 30, 2013 SecurityLoan
Financing Receivable, Modifications [Line Items]
Number of Loans	12		15		31		69
Pre-Modification Outstanding Recorded Investment	$ 1,210,000	[1]	$ 1,785,000	[1]	$ 3,252,000	[1]	$ 10,470,000	[1]
Post-Modification Outstanding Recorded Investment	1,179,000	[1]	1,758,000	[1]	3,198,000	[1]	10,036,000	[1]
Total Difference in Recorded Investment	(31,000)		(27,000)		(54,000)		(434,000)
Loan forgiveness			100,000
Principal Deferral [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans	3		1		4		8
Pre-Modification Outstanding Recorded Investment	868,000	[1]	278,000	[1]	997,000	[1]	2,538,000	[1]
Post-Modification Outstanding Recorded Investment	841,000	[1]	278,000	[1]	968,000	[1]	2,151,000	[1]
Total Difference in Recorded Investment	(27,000)				(29,000)		(387,000)
Interest Rate Reduction and Maturity Date Extension [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans	2		2		2		2
Pre-Modification Outstanding Recorded Investment	96,000	[1]	664,000	[1]	96,000	[1]	664,000	[1]
Post-Modification Outstanding Recorded Investment	96,000	[1]	644,000	[1]	96,000	[1]	644,000	[1]
Total Difference in Recorded Investment			(20,000)				(20,000)
Principal Forgiveness [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans						[2]	1	[2]
Pre-Modification Outstanding Recorded Investment						[1],[2]	4,339,000	[1],[2]
Post-Modification Outstanding Recorded Investment						[1],[2]	4,339,000	[1],[2]
Total Difference in Recorded Investment						[2]		[2]
Chapter 7 Bankruptcy [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans	7	[3]	11	[3]	24	[3]	56	[3]
Pre-Modification Outstanding Recorded Investment	246,000	[1],[3]	789,000	[1],[3]	1,140,000	[1],[3]	2,124,000	[1],[3]
Post-Modification Outstanding Recorded Investment	242,000	[1],[3]	782,000	[1],[3]	1,115,000	[1],[3]	2,097,000	[1],[3]
Total Difference in Recorded Investment	(4,000)	[3]	(7,000)	[3]	(25,000)	[3]	(27,000)	[3]
Maturity Date Extension [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans					1		1
Pre-Modification Outstanding Recorded Investment					1,019,000	[1]	751,000	[1]
Post-Modification Outstanding Recorded Investment					1,019,000	[1]	751,000	[1]
Total Difference in Recorded Investment
Interest Rate Reduction [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans			1				1
Pre-Modification Outstanding Recorded Investment		[1]	54,000	[1]		[1]	54,000	[1]
Post-Modification Outstanding Recorded Investment		[1]	54,000	[1]		[1]	54,000	[1]
Total Difference in Recorded Investment							0
Commercial Real Estate [Member] | Principal Deferral [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans	1				2		3
Pre-Modification Outstanding Recorded Investment	487,000	[1]		[1]	616,000	[1]	1,541,000	[1]
Post-Modification Outstanding Recorded Investment	475,000	[1]		[1]	602,000	[1]	1,288,000	[1]
Total Difference in Recorded Investment	(12,000)				(14,000)		(253,000)
Commercial Real Estate [Member] | Interest Rate Reduction and Maturity Date Extension [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans			2				2
Pre-Modification Outstanding Recorded Investment		[1]	664,000	[1]		[1]	664,000	[1]
Post-Modification Outstanding Recorded Investment		[1]	644,000	[1]		[1]	644,000	[1]
Total Difference in Recorded Investment			(20,000)				(20,000)
Commercial Real Estate [Member] | Principal Forgiveness [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans						[3]	1	[3]
Pre-Modification Outstanding Recorded Investment						[1],[2]	4,339,000	[1],[2]
Post-Modification Outstanding Recorded Investment						[1],[2]	4,339,000	[1],[2]
Total Difference in Recorded Investment						[3]		[3]
Commercial Real Estate [Member] | Chapter 7 Bankruptcy [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans	1	[3]		[3]	1	[3]	7	[3]
Pre-Modification Outstanding Recorded Investment	83,000	[1],[3]		[1],[3]	83,000	[1],[3]	258,000	[1],[3]
Post-Modification Outstanding Recorded Investment	83,000	[1],[3]		[1],[3]	83,000	[1],[3]	255,000	[1],[3]
Total Difference in Recorded Investment		[3]		[3]		[3]	(3,000)	[3]
Commercial and Industrial [Member] | Principal Deferral [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans	2		1		2		2
Pre-Modification Outstanding Recorded Investment	381,000	[1]	278,000	[1]	381,000	[1]	670,000	[1]
Post-Modification Outstanding Recorded Investment	366,000	[1]	278,000	[1]	366,000	[1]	665,000	[1]
Total Difference in Recorded Investment	(15,000)				(15,000)		(5,000)
Commercial and Industrial [Member] | Chapter 7 Bankruptcy [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans					1	[3]	1	[3]
Pre-Modification Outstanding Recorded Investment					287,000	[1],[3]	3,000	[1],[3]
Post-Modification Outstanding Recorded Investment					286,000	[1],[3]	3,000	[1],[3]
Total Difference in Recorded Investment					(1,000)	[3]		[3]
Commercial and Industrial [Member] | Maturity Date Extension [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans							1
Pre-Modification Outstanding Recorded Investment						[1]	751,000	[1]
Post-Modification Outstanding Recorded Investment						[1]	751,000	[1]
Total Difference in Recorded Investment
Commercial Construction [Member] | Maturity Date Extension [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans					1
Pre-Modification Outstanding Recorded Investment					1,019,000	[1]	0	[1]
Post-Modification Outstanding Recorded Investment					1,019,000	[1]		[1]
Total Difference in Recorded Investment
Residential Mortgage [Member] | Principal Deferral [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans							2
Pre-Modification Outstanding Recorded Investment						[1]	153,000	[1]
Post-Modification Outstanding Recorded Investment						[1]	153,000	[1]
Total Difference in Recorded Investment
Residential Mortgage [Member] | Chapter 7 Bankruptcy [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans	2	[3]		[3]	7	[3]	8	[3]
Pre-Modification Outstanding Recorded Investment	135,000	[1],[3]		[1],[3]	464,000	[1],[3]	353,000	[1],[3]
Post-Modification Outstanding Recorded Investment	134,000	[1],[3]		[1],[3]	461,000	[1],[3]	344,000	[1],[3]
Total Difference in Recorded Investment	(1,000)	[3]		[3]	(3,000)	[3]	(9,000)	[3]
Residential Mortgage [Member] | Interest Rate Reduction [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans			1				1
Pre-Modification Outstanding Recorded Investment		[1]	54,000	[1]		[1]	54,000	[1]
Post-Modification Outstanding Recorded Investment		[1]	54,000	[1]		[1]	54,000	[1]
Total Difference in Recorded Investment
Home Equity [Member] | Principal Deferral [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans							1
Pre-Modification Outstanding Recorded Investment						[1]	174,000	[1]
Post-Modification Outstanding Recorded Investment						[1]	45,000	[1]
Total Difference in Recorded Investment							(129,000)
Home Equity [Member] | Interest Rate Reduction and Maturity Date Extension [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans	2				2
Pre-Modification Outstanding Recorded Investment	96,000	[1]		[1]	96,000	[1]		[1]
Post-Modification Outstanding Recorded Investment	96,000	[1]		[1]	96,000	[1]		[1]
Total Difference in Recorded Investment
Home Equity [Member] | Chapter 7 Bankruptcy [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans	2	[3]	8	[3]	12	[3]	31	[3]
Pre-Modification Outstanding Recorded Investment	14,000	[1],[3]	772,000	[1],[3]	283,000	[1],[3]	1,420,000	[1],[3]
Post-Modification Outstanding Recorded Investment	14,000	[1],[3]	767,000	[1],[3]	265,000	[1],[3]	1,407,000	[1],[3]
Total Difference in Recorded Investment		[3]	(5,000)	[3]	(18,000)	[3]	(13,000)	[3]
Installment and Other Consumer [Member] | Chapter 7 Bankruptcy [Member]
Financing Receivable, Modifications [Line Items]
Number of Loans	2	[3]	3	[3]	3	[3]	9	[3]
Pre-Modification Outstanding Recorded Investment	14,000	[1],[3]	17,000	[1],[3]	23,000	[1],[3]	90,000	[1],[3]
Post-Modification Outstanding Recorded Investment	11,000	[1],[3]	15,000	[1],[3]	20,000	[1],[3]	88,000	[1],[3]
Total Difference in Recorded Investment	$ (3,000)	[3]	$ (2,000)	[3]	$ (3,000)	[3]	$ (2,000)	[3]

[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] This loan had debt forgiveness of $0.1 million to the customer; however, the loan was previously charged off to a balance below the actual contractual balance.

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