Non-performing Assets and Impaired Loans - Payment Status by Class of Loan (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	$ 5,039	$ 5,197
Loans Not Past Due	1,740,301	1,372,275
Total	$ 1,745,340	$ 1,377,472
Total Past Due, Percentage of Total Loans	0.29%	0.38%
Loans Not Past Due, Percentage of Total Loans	99.71%	99.62%
Commercial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	$ 580	$ 1,181
Loans Not Past Due	802,212	671,878
Total	802,792	673,059
Commercial [Member] | Owner Occupied Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	499	748
Loans Not Past Due	267,782	227,632
Total	268,281	228,380
Commercial [Member] | Non Owner Occupied Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	49	413
Loans Not Past Due	326,350	296,886
Total	326,399	297,299
Commercial [Member] | Residential Development [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans Not Past Due	5,018	2,027
Total	5,018	2,027
Commercial [Member] | Development & Spec Land Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans Not Past Due	18,183	12,097
Total	18,183	12,097
Commercial [Member] | Commercial and Industrial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	32	20
Loans Not Past Due	184,879	133,236
Total	184,911	133,256
Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,466	1,266
Loans Not Past Due	577,901	381,916
Total	579,367	383,182
Real Estate [Member] | Residential Mortgage [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,466	1,266
Loans Not Past Due	413,458	241,255
Total	414,924	242,521
Real Estate [Member] | Residential Construction [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans Not Past Due	19,751	11,505
Total	19,751	11,505
Real Estate [Member] | Mortgage Warehousing [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans Not Past Due	144,692	129,156
Total	144,692	129,156
Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	2,993	2,750
Loans Not Past Due	360,188	318,481
Total	363,181	321,231
Consumer [Member] | Direct Installment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	116	127
Loans Not Past Due	54,225	40,010
Total	54,341	40,137
Consumer [Member] | Direct Installment Purchased [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans Not Past Due	153	219
Total	153	219
Consumer [Member] | Indirect Installment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,481	1,332
Loans Not Past Due	150,042	140,536
Total	151,523	141,868
Consumer [Member] | Home Equity Loan [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,396	1,291
Loans Not Past Due	155,768	137,716
Total	157,164	139,007
30 - 59 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	$ 4,168	$ 3,807
Total Past Due, Percentage of Total Loans	0.24%	0.28%
30 - 59 Days Past Due [Member] | Commercial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	$ 562	$ 535
30 - 59 Days Past Due [Member] | Commercial [Member] | Owner Occupied Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	481	103
30 - 59 Days Past Due [Member] | Commercial [Member] | Non Owner Occupied Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	49	413
30 - 59 Days Past Due [Member] | Commercial [Member] | Commercial and Industrial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	32	19
30 - 59 Days Past Due [Member] | Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,121	1,033
30 - 59 Days Past Due [Member] | Real Estate [Member] | Residential Mortgage [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,121	1,033
30 - 59 Days Past Due [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	2,485	2,239
30 - 59 Days Past Due [Member] | Consumer [Member] | Direct Installment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	106	113
30 - 59 Days Past Due [Member] | Consumer [Member] | Indirect Installment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,186	1,042
30 - 59 Days Past Due [Member] | Consumer [Member] | Home Equity Loan [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,193	1,084
60 - 89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	$ 843	$ 1,275
Total Past Due, Percentage of Total Loans	0.05%	0.09%
60 - 89 Days Past Due [Member] | Commercial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	$ 18	$ 646
60 - 89 Days Past Due [Member] | Commercial [Member] | Owner Occupied Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	18	645
60 - 89 Days Past Due [Member] | Commercial [Member] | Commercial and Industrial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		1
60 - 89 Days Past Due [Member] | Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	344	193
60 - 89 Days Past Due [Member] | Real Estate [Member] | Residential Mortgage [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	344	193
60 - 89 Days Past Due [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	481	436
60 - 89 Days Past Due [Member] | Consumer [Member] | Direct Installment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	10	4
60 - 89 Days Past Due [Member] | Consumer [Member] | Indirect Installment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	268	243
60 - 89 Days Past Due [Member] | Consumer [Member] | Home Equity Loan [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	203	189
Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	$ 28	$ 115
Total Past Due, Percentage of Total Loans	0.00%	0.01%
Greater than 90 Days Past Due [Member] | Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	$ 1	$ 40
Greater than 90 Days Past Due [Member] | Real Estate [Member] | Residential Mortgage [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1	40
Greater than 90 Days Past Due [Member] | Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	27	75
Greater than 90 Days Past Due [Member] | Consumer [Member] | Direct Installment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		10
Greater than 90 Days Past Due [Member] | Consumer [Member] | Indirect Installment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	$ 27	47
Greater than 90 Days Past Due [Member] | Consumer [Member] | Home Equity Loan [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		$ 18