Credit Quality of Loans and Allowance for Loan Losses - Roll Forward of Activity In Allowance for Loan Losses (Details) - USD ($) $ in Thousands	6 Months Ended
Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Allowance for loan losses by portfolio [Roll Forward]
Beginning balance	$ 26,888	$ 24,372
Charge-offs	(4,638)	(15,565)
Recoveries	824	567
Provision	440	15,300
Ending balance	23,514	24,674
Ending balance: individually evaluated for impairment	4,838	4,352
Ending balance: collectively evaluated for impairment	18,676	20,322
Loans:
Ending balance	1,057,963	1,240,253	$ 1,183,426
Ending balance: individually evaluated for impairment	74,550	56,463
Ending balance: collectively evaluated for impairment	983,413	1,183,294
Ending balance: loans acquired with deteriorated credit quality		496
Commercial, financial and agricultural
Allowance for loan losses by portfolio [Roll Forward]
Beginning balance	20,577	16,057
Charge-offs	(3,647)	(11,319)
Recoveries	696	290
Provision	172	13,272
Ending balance	17,798	18,300
Ending balance: individually evaluated for impairment	4,452	3,092
Ending balance: collectively evaluated for impairment	13,346	15,208
Loans:
Ending balance	354,944	451,767	435,207
Ending balance: individually evaluated for impairment	40,228	35,276
Ending balance: collectively evaluated for impairment	314,716	416,491
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	(6)	(1)
Recoveries	0	0
Provision	(201)	623
Ending balance	389	1,207
Ending balance: individually evaluated for impairment	49	9
Ending balance: collectively evaluated for impairment	340	1,198
Loans:
Ending balance	98,108	98,695	90,287
Ending balance: individually evaluated for impairment	717	25
Ending balance: collectively evaluated for impairment	97,391	98,670
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	(216)	(3,448)
Recoveries	6	33
Provision	(460)	1,845
Ending balance	3,223	3,814
Ending balance: individually evaluated for impairment	126	1,120
Ending balance: collectively evaluated for impairment	3,097	2,694
Loans:
Ending balance	414,526	461,064	448,406
Ending balance: individually evaluated for impairment	29,917	19,526
Ending balance: collectively evaluated for impairment	384,609	441,108
Ending balance: loans acquired with deteriorated credit quality		430
Real estate – residential
Allowance for loan losses by portfolio [Roll Forward]
Beginning balance	837	940
Charge-offs	(321)	(198)
Recoveries	1	96
Provision	623	(438)
Ending balance	1,140	400
Ending balance: individually evaluated for impairment	198	28
Ending balance: collectively evaluated for impairment	942	372
Loans:
Ending balance	141,104	156,394	146,751
Ending balance: individually evaluated for impairment	3,623	1,325
Ending balance: collectively evaluated for impairment	137,481	155,003
Ending balance: loans acquired with deteriorated credit quality		66
Installment loans to individuals
Allowance for loan losses by portfolio [Roll Forward]
Beginning balance	957	1,395
Charge-offs	(448)	(599)
Recoveries	121	148
Provision	323	(1)
Ending balance	953	943
Ending balance: individually evaluated for impairment	13	103
Ending balance: collectively evaluated for impairment	940	840
Loans:
Ending balance	47,406	70,031	56,398
Ending balance: individually evaluated for impairment	65	311
Ending balance: collectively evaluated for impairment	47,341	69,720
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	632	866	732
Ending balance: individually evaluated for impairment	0	0
Ending balance: collectively evaluated for impairment	632	866
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	(17)	1
Ending balance	8	7
Ending balance: individually evaluated for impairment	0	0
Ending balance: collectively evaluated for impairment	8	7
Loans:
Ending balance	1,243	1,436	$ 5,645
Ending balance: individually evaluated for impairment	0	0
Ending balance: collectively evaluated for impairment	$ 1,243	1,436
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.

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