Allowance for Loan Losses (Details 1) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Rollforward of the allowance for loan losses
Beginning balance	$ 42,923	$ 42,859	$ 42,737	$ 42,437
Charge-offs	(1,414)	(813)	(3,012)	(2,767)
Recoveries	890	622	1,174	1,198
Net (charge-offs) recoveries	(524)	(191)	(1,838)	(1,569)
Provision for loan losses		1,164		2,943
Benefit attributable to FDIC loss-share agreements		54		(116)
Recoveries payable to FDIC		212		403
Provision for loan losses	1,750	1,430	3,250	3,230
Ending balance	44,149	44,098	44,149	44,098
Period-End Amount Allocated to:
Individually evaluated for impairment					$ 3,208	$ 7,619
Collectively evaluated for impairment					38,781	34,307
Purchased with deteriorated credit quality	42,923	42,859	42,737	42,437	44,149	44,098
Receivables Acquired with Deteriorated Credit Quality
Rollforward of the allowance for loan losses
Ending balance	2,160	2,172	2,160	2,172
Period-End Amount Allocated to:
Purchased with deteriorated credit quality	2,160	2,172	2,160	2,172	2,160	2,172
Commercial, financial, agricultural
Rollforward of the allowance for loan losses
Beginning balance	5,112	4,171	5,486	4,186
Charge-offs	(304)	(48)	(1,136)	(705)
Recoveries	64	105	121	158
Net (charge-offs) recoveries	(240)	57	(1,015)	(547)
Provision for loan losses		265		866
Benefit attributable to FDIC loss-share agreements		15		0
Recoveries payable to FDIC		4		7
Provision for loan losses	220	284	621	873
Ending balance	5,092	4,512	5,092	4,512
Period-End Amount Allocated to:
Individually evaluated for impairment					166	164
Collectively evaluated for impairment					4,587	3,947
Purchased with deteriorated credit quality	5,112	4,171	5,486	4,186	5,092	4,512
Commercial, financial, agricultural | Receivables Acquired with Deteriorated Credit Quality
Rollforward of the allowance for loan losses
Ending balance	339	401	339	401
Period-End Amount Allocated to:
Purchased with deteriorated credit quality	339	401	339	401	339	401
Real estate – construction
Rollforward of the allowance for loan losses
Beginning balance	2,119	1,943	2,380	1,852
Charge-offs		0	0	0
Recoveries	3	5	34	11
Net (charge-offs) recoveries	3	5	34	11
Provision for loan losses		315		400
Benefit attributable to FDIC loss-share agreements		0		0
Recoveries payable to FDIC		6		6
Provision for loan losses	458	321	166	406
Ending balance	2,580	2,269	2,580	2,269
Period-End Amount Allocated to:
Individually evaluated for impairment					2	0
Collectively evaluated for impairment					2,578	2,269
Purchased with deteriorated credit quality	2,119	1,943	2,380	1,852	2,580	2,269
Real estate – construction | Receivables Acquired with Deteriorated Credit Quality
Rollforward of the allowance for loan losses
Ending balance	0	0	0	0
Period-End Amount Allocated to:
Purchased with deteriorated credit quality	0	0	0	0	0	0
Real estate – 1-4 family mortgage
Rollforward of the allowance for loan losses
Beginning balance	12,162	14,542	14,294	13,908
Charge-offs	(551)	(387)	(826)	(503)
Recoveries	64	170	146	565
Net (charge-offs) recoveries	(487)	(217)	(680)	62
Provision for loan losses		(186)		179
Benefit attributable to FDIC loss-share agreements		(78)		(115)
Recoveries payable to FDIC		158		185
Provision for loan losses	429	(106)	(1,510)	249
Ending balance	12,104	14,219	12,104	14,219
Period-End Amount Allocated to:
Individually evaluated for impairment					878	4,924
Collectively evaluated for impairment					10,534	8,951
Purchased with deteriorated credit quality	12,162	14,542	14,294	13,908	12,104	14,219
Real estate – 1-4 family mortgage | Receivables Acquired with Deteriorated Credit Quality
Rollforward of the allowance for loan losses
Ending balance	692	344	692	344
Period-End Amount Allocated to:
Purchased with deteriorated credit quality	692	344	692	344	692	344
Real estate – commercial mortgage
Rollforward of the allowance for loan losses
Beginning balance	22,073	20,775	19,059	21,111
Charge-offs	(434)	(186)	(661)	(1,187)
Recoveries	717	309	812	401
Net (charge-offs) recoveries	283	123	151	(786)
Provision for loan losses		624		1,154
Benefit attributable to FDIC loss-share agreements		117		(1)
Recoveries payable to FDIC		44		205
Provision for loan losses	244	785	3,390	1,358
Ending balance	22,600	21,683	22,600	21,683
Period-End Amount Allocated to:
Individually evaluated for impairment					2,159	2,531
Collectively evaluated for impairment					19,313	17,726
Purchased with deteriorated credit quality	22,073	20,775	19,059	21,111	22,600	21,683
Real estate – commercial mortgage | Receivables Acquired with Deteriorated Credit Quality
Rollforward of the allowance for loan losses
Ending balance	1,128	1,426	1,128	1,426
Period-End Amount Allocated to:
Purchased with deteriorated credit quality	1,128	1,426	1,128	1,426	1,128	1,426
Installment loans to individuals
Rollforward of the allowance for loan losses
Beginning balance	1,457	1,428	1,518	1,380
Charge-offs	(125)	(192)	(389)	(372)
Recoveries	42	33	61	63
Net (charge-offs) recoveries	(83)	(159)	(328)	(309)
Provision for loan losses		146		344
Benefit attributable to FDIC loss-share agreements		0		0
Recoveries payable to FDIC		0		0
Provision for loan losses	399	146	583	344
Ending balance	1,773	1,415	1,773	1,415
Period-End Amount Allocated to:
Individually evaluated for impairment					3	0
Collectively evaluated for impairment					1,769	1,414
Purchased with deteriorated credit quality	1,457	1,428	1,518	1,380	1,773	1,415
Installment loans to individuals | Receivables Acquired with Deteriorated Credit Quality
Rollforward of the allowance for loan losses
Ending balance	1	1	1	1
Period-End Amount Allocated to:
Purchased with deteriorated credit quality	$ 1	$ 1	$ 1	$ 1	$ 1	$ 1