Non-performing Loans and Impaired Loans - Payment Status by Class of Loan (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due	$ 2,041	$ 5,998
60 - 89 Days Past Due	651	744
Greater than 90 Days Past Due	2	54
Total Past Due	2,694	6,796
Loans Not Past Due	1,077,537	1,181,670
Total	1,080,231	1,188,466
30 - 59 Days Past Due, Percentage of Total Loans	0.19%	0.50%
60 - 89 Days Past Due, Percentage of Total Loans	0.06%	0.06%
Greater than 90 Days Past Due, Percentage of Total Loans	0.00%	0.00%
Total Past Due, Percentage of Total Loans	0.25%	0.57%
Loans Not Past Due, Percentage of Total Loans	99.75%	99.43%
Commercial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due	157	3,414
60 - 89 Days Past Due		182
Greater than 90 Days Past Due
Total Past Due	157	3,596
Loans Not Past Due	498,667	455,962
Total	498,824	459,558
Commercial [Member] | Owner Occupied Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due	99	2,207
60 - 89 Days Past Due		19
Greater than 90 Days Past Due
Total Past Due	99	2,226
Loans Not Past Due	153,014	160,468
Total	153,113	162,694
Commercial [Member] | Non Owner Occupied Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due	45	669
60 - 89 Days Past Due		147
Greater than 90 Days Past Due
Total Past Due	45	816
Loans Not Past Due	229,609	200,947
Total	229,654	201,763
Commercial [Member] | Residential Development [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due
60 - 89 Days Past Due
Greater than 90 Days Past Due
Total Past Due
Loans Not Past Due	242	1,056
Total	242	1,056
Commercial [Member] | Development & Spec Land Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due
60 - 89 Days Past Due
Greater than 90 Days Past Due
Total Past Due
Loans Not Past Due	15,621	6,963
Total	15,621	6,963
Commercial [Member] | Commercial and Industrial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due	13	538
60 - 89 Days Past Due		16
Greater than 90 Days Past Due
Total Past Due	13	554
Loans Not Past Due	100,181	86,528
Total	100,194	87,082
Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due	695	167
60 - 89 Days Past Due	351
Greater than 90 Days Past Due	2	2
Total Past Due	1,048	169
Loans Not Past Due	301,388	440,410
Total	302,436	440,579
Real Estate [Member] | Residential mortgage [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due	695	167
60 - 89 Days Past Due	351
Greater than 90 Days Past Due	2	2
Total Past Due	1,048	169
Loans Not Past Due	178,916	181,281
Total	179,964	181,450
Real Estate [Member] | Residential Construction [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due
60 - 89 Days Past Due
Greater than 90 Days Past Due
Total Past Due
Loans Not Past Due	8,881	7,681
Total	8,881	7,681
Real Estate [Member] | Mortgage Warehouse [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due
60 - 89 Days Past Due
Greater than 90 Days Past Due
Total Past Due
Loans Not Past Due	113,591	251,448
Total	113,591	251,448
Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due	1,189	2,417
60 - 89 Days Past Due	300	562
Greater than 90 Days Past Due		52
Total Past Due	1,489	3,031
Loans Not Past Due	277,482	285,298
Total	278,971	288,329
Consumer [Member] | Direct Installment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due	122	240
60 - 89 Days Past Due	13	64
Greater than 90 Days Past Due		26
Total Past Due	135	330
Loans Not Past Due	28,833	27,501
Total	28,968	27,831
Consumer [Member] | Direct Installment Purchased [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due
60 - 89 Days Past Due
Greater than 90 Days Past Due
Total Past Due
Loans Not Past Due	331	429
Total	331	429
Consumer [Member] | Indirect Installment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due	894	1,105
60 - 89 Days Past Due	60	177
Greater than 90 Days Past Due		26
Total Past Due	954	1,308
Loans Not Past Due	128,496	132,173
Total	129,450	133,481
Consumer [Member] | Home Equity [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due	173	1,072
60 - 89 Days Past Due	227	321
Greater than 90 Days Past Due
Total Past Due	400	1,393
Loans Not Past Due	119,822	125,195
Total	$ 120,222	$ 126,588