Loans and Allowance for Loan Losses - Activity for Loans Categorized as Troubled Debt Restructurings (Detail) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Commercial and Industrial [Member]
Schedule Of Troubled Debt Restructured Loans [Line Items]
Beginning Balance	$ 2,266,000	$ 4,665,000	$ 2,721,000	$ 4,553,000
Charge-Offs	0	(60,000)	(35,000)	(172,000)
Payments	(324,000)	(268,000)	(1,902,000)	(763,000)
Transfers to ORE	0	(45,000)	(74,000)	(96,000)
Net Additions/Deletions	466,000	123,000	1,698,000	893,000
Ending Balance	2,408,000	4,415,000	2,408,000	4,415,000
Commercial Vacant Land, Land Development, and Residential Construction [Member]
Schedule Of Troubled Debt Restructured Loans [Line Items]
Beginning Balance	5,440,000	3,250,000	3,071,000	5,100,000
Charge-Offs	0	0	(725,000)	0
Payments	(303,000)	(55,000)	(456,000)	(1,952,000)
Transfers to ORE	0	0	0	(351,000)
Net Additions/Deletions	0	0	3,247,000	398,000
Ending Balance	5,137,000	3,195,000	5,137,000	3,195,000
Commercial Real Estate - Owner Occupied [Member]
Schedule Of Troubled Debt Restructured Loans [Line Items]
Beginning Balance	3,580,000	6,809,000	4,116,000	6,183,000
Charge-Offs	0	(12,000)	(70,000)	(426,000)
Payments	(271,000)	(2,750,000)	(1,310,000)	(3,317,000)
Transfers to ORE	0	0	(363,000)	0
Net Additions/Deletions	(652,000)	105,000	284,000	1,712,000
Ending Balance	2,657,000	4,152,000	2,657,000	4,152,000
Commercial Real Estate - Non-Owner Occupied [Member]
Schedule Of Troubled Debt Restructured Loans [Line Items]
Beginning Balance	34,424,000	16,881,000	37,672,000	12,037,000
Charge-Offs	0	(474,000)	(716,000)	(499,000)
Payments	(1,690,000)	(178,000)	(5,475,000)	(689,000)
Transfers to ORE	(350,000)	(579,000)	(1,153,000)	(579,000)
Net Additions/Deletions	68,000	18,043,000	2,124,000	23,423,000
Ending Balance	32,452,000	33,693,000	32,452,000	33,693,000
Commercial Real Estate - Multi-Family and Residential Rental [Member]
Schedule Of Troubled Debt Restructured Loans [Line Items]
Beginning Balance	2,775,000	4,985,000	3,026,000	12,626,000
Charge-Offs	0	0	(15,000)	(2,180,000)
Payments	(295,000)	(263,000)	(530,000)	(5,914,000)
Transfers to ORE	0	0	0	0
Net Additions/Deletions	343,000	0	342,000	190,000
Ending Balance	2,823,000	4,722,000	2,823,000	4,722,000
Retail Home Equity and Other [Member]
Schedule Of Troubled Debt Restructured Loans [Line Items]
Beginning Balance	2,029,000	159,000	155,000	164,000
Charge-Offs	0	0	0	0
Payments	(16,000)	(2,000)	(21,000)	(7,000)
Transfers to ORE	0	0	0	0
Net Additions/Deletions	0	0	1,879,000	0
Ending Balance	2,013,000	157,000	2,013,000	157,000
Retail 1-4 Family Mortgages [Member]
Schedule Of Troubled Debt Restructured Loans [Line Items]
Beginning Balance	0	0	0	0
Charge-Offs	0	0	0	0
Payments	0	0	0	0
Transfers to ORE	0	0	0	0
Net Additions/Deletions	0	0	0	0
Ending Balance	$ 0	$ 0	$ 0	$ 0