Credit Quality of Loans and Allowance for Loan Losses - Roll Forward of Activity In Allowance for Loan Losses (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Allowance for loan losses by portfolio [Roll Forward]
Beginning balance	$ 26,888	$ 24,372
Charge-offs	(1,836)	(2,906)
Recoveries	319	312
Provision	0	2,800
Ending balance	25,371	24,578
Ending balance: individually evaluated for impairment	6,164	6,215
Ending balance: collectively evaluated for impairment	19,207	18,363
Loans:
Ending balance	1,137,255	1,272,000	$ 1,183,426
Ending balance: individually evaluated for impairment	83,427	58,438
Ending balance: collectively evaluated for impairment	1,053,828	1,213,059
Ending balance: loans acquired with deteriorated credit quality		503
Commercial, financial and agricultural
Allowance for loan losses by portfolio [Roll Forward]
Beginning balance	20,577	16,057
Charge-offs	(1,524)	(1,705)
Recoveries	276	154
Provision	(264)	3,832
Ending balance	19,065	18,338
Ending balance: individually evaluated for impairment	5,968	4,173
Ending balance: collectively evaluated for impairment	13,097	14,165
Loans:
Ending balance	401,048	469,815	435,207
Ending balance: individually evaluated for impairment	55,092	35,346
Ending balance: collectively evaluated for impairment	345,956	434,469
Ending balance: loans acquired with deteriorated credit quality		0
Real estate - construction
Allowance for loan losses by portfolio [Roll Forward]
Beginning balance	596	585
Charge-offs	(2)	0
Recoveries	0	0
Provision	159	(321)
Ending balance	753	264
Ending balance: individually evaluated for impairment	94	9
Ending balance: collectively evaluated for impairment	659	255
Loans:
Ending balance	94,679	100,248	90,287
Ending balance: individually evaluated for impairment	192	26
Ending balance: collectively evaluated for impairment	94,487	100,222
Ending balance: loans acquired with deteriorated credit quality		0
Real estate – commercial
Allowance for loan losses by portfolio [Roll Forward]
Beginning balance	3,893	5,384
Charge-offs	(86)	(823)
Recoveries	6	10
Provision	(106)	(238)
Ending balance	3,707	4,333
Ending balance: individually evaluated for impairment	76	1,656
Ending balance: collectively evaluated for impairment	3,631	2,677
Loans:
Ending balance	438,779	464,859	448,406
Ending balance: individually evaluated for impairment	26,005	20,623
Ending balance: collectively evaluated for impairment	412,774	443,802
Ending balance: loans acquired with deteriorated credit quality		434
Real estate – residential
Allowance for loan losses by portfolio [Roll Forward]
Beginning balance	837	940
Charge-offs	(3)	(117)
Recoveries	1	90
Provision	64	(249)
Ending balance	899	664
Ending balance: individually evaluated for impairment	20	217
Ending balance: collectively evaluated for impairment	879	447
Loans:
Ending balance	145,671	159,426	146,751
Ending balance: individually evaluated for impairment	2,088	1,956
Ending balance: collectively evaluated for impairment	143,583	157,401
Ending balance: loans acquired with deteriorated credit quality		69
Installment loans to individuals
Allowance for loan losses by portfolio [Roll Forward]
Beginning balance	957	1,395
Charge-offs	(221)	(261)
Recoveries	36	58
Provision	146	(222)
Ending balance	918	970
Ending balance: individually evaluated for impairment	6	160
Ending balance: collectively evaluated for impairment	912	810
Loans:
Ending balance	50,888	75,258	56,398
Ending balance: individually evaluated for impairment	50	487
Ending balance: collectively evaluated for impairment	50,838	74,771
Ending balance: loans acquired with deteriorated credit quality		0
Lease financing receivable
Allowance for loan losses by portfolio [Roll Forward]
Beginning balance	3	5
Charge-offs	0	0
Recoveries	0	0
Provision	0	(2)
Ending balance	3	3
Ending balance: individually evaluated for impairment	0	0
Ending balance: collectively evaluated for impairment	3	3
Loans:
Ending balance	692	969	732
Ending balance: individually evaluated for impairment	0	0
Ending balance: collectively evaluated for impairment	692	969
Ending balance: loans acquired with deteriorated credit quality		0
Other
Allowance for loan losses by portfolio [Roll Forward]
Beginning balance	25	6
Charge-offs	0	0
Recoveries	0	0
Provision	1	0
Ending balance	26	6
Ending balance: individually evaluated for impairment	0	0
Ending balance: collectively evaluated for impairment	26	6
Loans:
Ending balance	5,498	1,425	$ 5,645
Ending balance: individually evaluated for impairment	0	0
Ending balance: collectively evaluated for impairment	$ 5,498	1,425
Ending balance: loans acquired with deteriorated credit quality		$ 0

The recorded balance, net of any applicable reductions (for example, unamortized accretable yield and allowance for loan losses). This relates to loans not accounted for debt securities with evidence of deterioration of credit quality since origination that were acquired by completion of a transfer for which it is probable, at acquisition, that the investor will be unable to collect all contractually required payments receivable.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 30
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=6379141&loc=d3e15032-111544

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 30
-Section 15
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=27045933&loc=d3e13503-111538

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Amount before allowance and after deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=65884687&loc=d3e4428-111522

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