Loans and Leases - Credit Quality Indicators (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases Held for Investment, Originated	$ 1,883,563	$ 1,626,625
Total Loans and Leases Held for Investment, Acquired	295,450
Grade: 1. Cash secured/ 2. Fully secured [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases Held for Investment, Originated	6,385	5,510
Total Loans and Leases Held for Investment, Acquired	1,411
Grade: 3. Strong [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases Held for Investment, Originated	28,205	26,414
Total Loans and Leases Held for Investment, Acquired	0
Grade: 4. Satisfactory [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases Held for Investment, Originated	73,179	63,588
Total Loans and Leases Held for Investment, Acquired	5,350
Grade: 5. Acceptable [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases Held for Investment, Originated	1,010,195	783,790
Total Loans and Leases Held for Investment, Acquired	238,207
Grade: 6. Pre-watch [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases Held for Investment, Originated	200,638	199,462
Total Loans and Leases Held for Investment, Acquired	20,791
Grade: 7. Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases Held for Investment, Originated	28,707	25,975
Total Loans and Leases Held for Investment, Acquired	9,637
Grade: 8. Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases Held for Investment, Originated	78,197	98,385
Total Loans and Leases Held for Investment, Acquired	4,829
Grade: 9. Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases Held for Investment, Originated	0	0
Total Loans and Leases Held for Investment, Acquired	0
Grade: 10. Loss [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases Held for Investment, Originated	0	0
Total Loans and Leases Held for Investment, Acquired	0
Internally Assigned Grades [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases Held for Investment, Originated	1,425,506	1,203,124
Total Loans and Leases Held for Investment, Acquired	280,225
Performing Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases Held for Investment, Originated	456,156	421,974
Total Loans and Leases Held for Investment, Acquired	15,225
Nonperforming Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases Held for Investment, Originated	1,901	1,527
Total Loans and Leases Held for Investment, Acquired	0
Performing and Nonperforming [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases Held for Investment, Originated	458,057	423,501
Total Loans and Leases Held for Investment, Acquired	15,225
Commercial, Financial and Agricultural [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases Held for Investment, Originated	479,980	457,827
Total Loans and Leases Held for Investment, Acquired	24,535
Commercial, Financial and Agricultural [Member] | Grade: 1. Cash secured/ 2. Fully secured [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases Held for Investment, Originated	968	4,248
Total Loans and Leases Held for Investment, Acquired	1,411
Commercial, Financial and Agricultural [Member] | Grade: 3. Strong [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases Held for Investment, Originated	17,328	14,013
Total Loans and Leases Held for Investment, Acquired	0
Commercial, Financial and Agricultural [Member] | Grade: 4. Satisfactory [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases Held for Investment, Originated	36,697	23,931
Total Loans and Leases Held for Investment, Acquired	1,181
Commercial, Financial and Agricultural [Member] | Grade: 5. Acceptable [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases Held for Investment, Originated	328,140	301,425
Total Loans and Leases Held for Investment, Acquired	18,446
Commercial, Financial and Agricultural [Member] | Grade: 6. Pre-watch [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases Held for Investment, Originated	61,098	65,993
Total Loans and Leases Held for Investment, Acquired	2,273
Commercial, Financial and Agricultural [Member] | Grade: 7. Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases Held for Investment, Originated	6,074	7,166
Total Loans and Leases Held for Investment, Acquired	417
Commercial, Financial and Agricultural [Member] | Grade: 8. Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases Held for Investment, Originated	29,675	41,051
Total Loans and Leases Held for Investment, Acquired	807
Commercial, Financial and Agricultural [Member] | Grade: 9. Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases Held for Investment, Originated	0	0
Total Loans and Leases Held for Investment, Acquired	0
Commercial, Financial and Agricultural [Member] | Grade: 10. Loss [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases Held for Investment, Originated	0	0
Total Loans and Leases Held for Investment, Acquired	0
Commercial, Financial and Agricultural [Member] | Internally Assigned Grades [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases Held for Investment, Originated	479,980	457,827
Total Loans and Leases Held for Investment, Acquired	24,535
Real Estate-Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases Held for Investment, Originated	759,342	628,478
Total Loans and Leases Held for Investment, Acquired	126,550
Real Estate-Commercial [Member] | Grade: 1. Cash secured/ 2. Fully secured [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases Held for Investment, Originated	0	0
Total Loans and Leases Held for Investment, Acquired	0
Real Estate-Commercial [Member] | Grade: 3. Strong [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases Held for Investment, Originated	10,877	8,504
Total Loans and Leases Held for Investment, Acquired	0
Real Estate-Commercial [Member] | Grade: 4. Satisfactory [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases Held for Investment, Originated	36,023	30,587
Total Loans and Leases Held for Investment, Acquired	3,561
Real Estate-Commercial [Member] | Grade: 5. Acceptable [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases Held for Investment, Originated	530,766	402,719
Total Loans and Leases Held for Investment, Acquired	102,122
Real Estate-Commercial [Member] | Grade: 6. Pre-watch [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases Held for Investment, Originated	119,117	123,129
Total Loans and Leases Held for Investment, Acquired	10,365
Real Estate-Commercial [Member] | Grade: 7. Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases Held for Investment, Originated	20,286	17,505
Total Loans and Leases Held for Investment, Acquired	8,853
Real Estate-Commercial [Member] | Grade: 8. Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases Held for Investment, Originated	42,273	46,034
Total Loans and Leases Held for Investment, Acquired	1,649
Real Estate-Commercial [Member] | Grade: 9. Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases Held for Investment, Originated	0	0
Total Loans and Leases Held for Investment, Acquired	0
Real Estate-Commercial [Member] | Grade: 10. Loss [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases Held for Investment, Originated	0	0
Total Loans and Leases Held for Investment, Acquired	0
Real Estate-Commercial [Member] | Internally Assigned Grades [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases Held for Investment, Originated	759,342	628,478
Total Loans and Leases Held for Investment, Acquired	126,550
Real Estate-Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases Held for Investment, Originated	91,904	79,887
Total Loans and Leases Held for Investment, Acquired	4,637
Real Estate-Construction [Member] | Grade: 1. Cash secured/ 2. Fully secured [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases Held for Investment, Originated	5,417	1,262
Total Loans and Leases Held for Investment, Acquired	0
Real Estate-Construction [Member] | Grade: 3. Strong [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases Held for Investment, Originated	0	3,897
Total Loans and Leases Held for Investment, Acquired	0
Real Estate-Construction [Member] | Grade: 4. Satisfactory [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases Held for Investment, Originated	450	8,731
Total Loans and Leases Held for Investment, Acquired	0
Real Estate-Construction [Member] | Grade: 5. Acceptable [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases Held for Investment, Originated	72,630	55,111
Total Loans and Leases Held for Investment, Acquired	4,637
Real Estate-Construction [Member] | Grade: 6. Pre-watch [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases Held for Investment, Originated	13,262	4,956
Total Loans and Leases Held for Investment, Acquired	0
Real Estate-Construction [Member] | Grade: 7. Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases Held for Investment, Originated	0	0
Total Loans and Leases Held for Investment, Acquired	0
Real Estate-Construction [Member] | Grade: 8. Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases Held for Investment, Originated	145	5,930
Total Loans and Leases Held for Investment, Acquired	0
Real Estate-Construction [Member] | Grade: 9. Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases Held for Investment, Originated	0	0
Total Loans and Leases Held for Investment, Acquired	0
Real Estate-Construction [Member] | Grade: 10. Loss [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases Held for Investment, Originated	0	0
Total Loans and Leases Held for Investment, Acquired	0
Real Estate-Construction [Member] | Internally Assigned Grades [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases Held for Investment, Originated	91,904	79,887
Total Loans and Leases Held for Investment, Acquired	4,637
Real Estate-Residential Secured for Business Purpose [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases Held for Investment, Originated	94,280	36,932
Total Loans and Leases Held for Investment, Acquired	124,503
Real Estate-Residential Secured for Business Purpose [Member] | Grade: 1. Cash secured/ 2. Fully secured [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases Held for Investment, Originated	0	0
Total Loans and Leases Held for Investment, Acquired	0
Real Estate-Residential Secured for Business Purpose [Member] | Grade: 3. Strong [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases Held for Investment, Originated	0	0
Total Loans and Leases Held for Investment, Acquired	0
Real Estate-Residential Secured for Business Purpose [Member] | Grade: 4. Satisfactory [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases Held for Investment, Originated	9	339
Total Loans and Leases Held for Investment, Acquired	608
Real Estate-Residential Secured for Business Purpose [Member] | Grade: 5. Acceptable [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases Held for Investment, Originated	78,659	24,535
Total Loans and Leases Held for Investment, Acquired	113,002
Real Estate-Residential Secured for Business Purpose [Member] | Grade: 6. Pre-watch [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases Held for Investment, Originated	7,161	5,384
Total Loans and Leases Held for Investment, Acquired	8,153
Real Estate-Residential Secured for Business Purpose [Member] | Grade: 7. Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases Held for Investment, Originated	2,347	1,304
Total Loans and Leases Held for Investment, Acquired	367
Real Estate-Residential Secured for Business Purpose [Member] | Grade: 8. Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases Held for Investment, Originated	6,104	5,370
Total Loans and Leases Held for Investment, Acquired	2,373
Real Estate-Residential Secured for Business Purpose [Member] | Grade: 9. Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases Held for Investment, Originated	0	0
Total Loans and Leases Held for Investment, Acquired	0
Real Estate-Residential Secured for Business Purpose [Member] | Grade: 10. Loss [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases Held for Investment, Originated	0	0
Total Loans and Leases Held for Investment, Acquired	0
Real Estate-Residential Secured for Business Purpose [Member] | Internally Assigned Grades [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases Held for Investment, Originated	94,280	36,932
Total Loans and Leases Held for Investment, Acquired	124,503
Real Estate-Residential Secured for Personal Purpose [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases Held for Investment, Originated	177,850	166,850
Total Loans and Leases Held for Investment, Acquired	3,305
Real Estate-Residential Secured for Personal Purpose [Member] | Performing Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases Held for Investment, Originated	177,053	166,338
Total Loans and Leases Held for Investment, Acquired	3,305
Real Estate-Residential Secured for Personal Purpose [Member] | Nonperforming Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases Held for Investment, Originated	797	512
Total Loans and Leases Held for Investment, Acquired	0
Real Estate-Residential Secured for Personal Purpose [Member] | Performing and Nonperforming [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases Held for Investment, Originated	177,850	166,850
Total Loans and Leases Held for Investment, Acquired	3,305
Real Estate-Home Equity Secured for Personal Purpose [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases Held for Investment, Originated	125,361	108,250
Total Loans and Leases Held for Investment, Acquired	11,594
Real Estate-Home Equity Secured for Personal Purpose [Member] | Performing Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases Held for Investment, Originated	125,086	108,035
Total Loans and Leases Held for Investment, Acquired	11,594
Real Estate-Home Equity Secured for Personal Purpose [Member] | Nonperforming Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases Held for Investment, Originated	275	215
Total Loans and Leases Held for Investment, Acquired	0
Real Estate-Home Equity Secured for Personal Purpose [Member] | Performing and Nonperforming [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases Held for Investment, Originated	125,361	108,250
Total Loans and Leases Held for Investment, Acquired	11,594
Loans to Individuals [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases Held for Investment, Originated	29,406	29,941
Total Loans and Leases Held for Investment, Acquired	326
Loans to Individuals [Member] | Performing Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases Held for Investment, Originated	29,233	29,576
Total Loans and Leases Held for Investment, Acquired	326
Loans to Individuals [Member] | Nonperforming Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases Held for Investment, Originated	173	365
Total Loans and Leases Held for Investment, Acquired	0
Loans to Individuals [Member] | Performing and Nonperforming [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases Held for Investment, Originated	29,406	29,941
Total Loans and Leases Held for Investment, Acquired	326
Lease Financings [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases Held for Investment, Originated	125,440	118,460
Total Loans and Leases Held for Investment, Acquired	0
Lease Financings [Member] | Performing Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases Held for Investment, Originated	124,784	118,025
Total Loans and Leases Held for Investment, Acquired	0
Lease Financings [Member] | Nonperforming Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases Held for Investment, Originated	656	435
Total Loans and Leases Held for Investment, Acquired	0
Lease Financings [Member] | Performing and Nonperforming [Member]
Financing Receivable, Recorded Investment [Line Items]
Total Loans and Leases Held for Investment, Originated	125,440	$ 118,460
Total Loans and Leases Held for Investment, Acquired	$ 0