Non-performing Assets and Impaired Loans - Payment Status by Class of Loan (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due	$ 2,156	$ 3,108
60 - 89 Days Past Due	456	344
Greater than 90 Days Past Due	203	49
Total Past Due	2,815	3,501
Loans Not Past Due	1,097,255	1,064,434
Total	1,100,070	1,067,935
30 - 59 Days Past Due, Percentage of Total Loans	0.20%	0.29%
60 - 89 Days Past Due, Percentage of Total Loans	0.04%	0.03%
Greater than 90 Days Past Due, Percentage of Total Loans	0.02%	0.00%
Total Past Due, Percentage of Total Loans	0.26%	0.33%
Loans Not Past Due, Percentage of Total Loans	99.74%	99.67%
Commercial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due	450	765
60 - 89 Days Past Due	127
Greater than 90 Days Past Due		45
Total Past Due	577	810
Loans Not Past Due	527,454	503,774
Total	528,031	504,584
Commercial [Member] | Owner Occupied Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due	218	341
60 - 89 Days Past Due	127
Total Past Due	345	341
Loans Not Past Due	173,169	155,921
Total	173,514	156,262
Commercial [Member] | Non-owner Occupied Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due	122	424
Greater than 90 Days Past Due		45
Total Past Due	122	469
Loans Not Past Due	230,103	224,244
Total	230,225	224,713
Commercial [Member] | Residential Development [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans Not Past Due	833	400
Total	833	400
Commercial [Member] | Development & Spec Land Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans Not Past Due	21,347	21,289
Total	21,347	21,289
Commercial [Member] | Commercial and Industrial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due	110
Total Past Due	110
Loans Not Past Due	102,002	101,920
Total	102,112	101,920
Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due	313	445
60 - 89 Days Past Due		87
Greater than 90 Days Past Due	3	2
Total Past Due	316	534
Loans Not Past Due	291,371	283,198
Total	291,687	283,732
Real Estate [Member] | Residential Mortgage [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due	313	445
60 - 89 Days Past Due		87
Greater than 90 Days Past Due	3	2
Total Past Due	316	534
Loans Not Past Due	180,533	175,534
Total	180,849	176,068
Real Estate [Member] | Residential Construction [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans Not Past Due	8,692	9,508
Total	8,692	9,508
Real Estate [Member] | Mortgage Warehousing [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans Not Past Due	102,146	98,156
Total	102,146	98,156
Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due	1,393	1,898
60 - 89 Days Past Due	329	257
Greater than 90 Days Past Due	200	2
Total Past Due	1,922	2,157
Loans Not Past Due	278,430	277,462
Total	280,352	279,619
Consumer [Member] | Direct Installment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due	67	120
60 - 89 Days Past Due	10	24
Greater than 90 Days Past Due	20
Total Past Due	97	144
Loans Not Past Due	30,459	29,839
Total	30,556	29,983
Consumer [Member] | Direct Installment Purchased [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans Not Past Due	270	294
Total	270	294
Consumer [Member] | Indirect Installment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due	771	1,011
60 - 89 Days Past Due	41	175
Greater than 90 Days Past Due	103	2
Total Past Due	915	1,188
Loans Not Past Due	130,479	130,196
Total	131,394	131,384
Consumer [Member] | Home Equity [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due	555	767
60 - 89 Days Past Due	278	58
Greater than 90 Days Past Due	77
Total Past Due	910	825
Loans Not Past Due	117,222	117,133
Total	$ 118,132	$ 117,958