Allowance for Loan Losses (Details 1) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2017	Mar. 31, 2016
Rollforward of the allowance for loan losses
Beginning balance	$ 42,737	$ 42,437
Charge-offs	(1,598)	(1,954)
Recoveries	284	576
Net (charge-offs) recoveries	(1,314)	(1,378)
Provision for loan losses		1,779
Benefit attributable to FDIC loss-share agreements		(170)
Recoveries payable to FDIC		191
Provision for loan losses	1,500	1,800
Ending balance	42,923	42,859
Period-End Amount Allocated to:
Individually evaluated for impairment			$ 3,977	$ 7,399
Collectively evaluated for impairment			36,227	33,438
Acquired with deteriorated credit quality	42,737	42,437	42,923	42,859
Receivables Acquired with Deteriorated Credit Quality
Rollforward of the allowance for loan losses
Ending balance	2,719	2,022
Period-End Amount Allocated to:
Acquired with deteriorated credit quality	2,719	2,022	2,719	2,022
Commercial, financial, agricultural
Rollforward of the allowance for loan losses
Beginning balance	5,486	4,186
Charge-offs	(832)	(657)
Recoveries	57	53
Net (charge-offs) recoveries	(775)	(604)
Provision for loan losses		601
Benefit attributable to FDIC loss-share agreements		(15)
Recoveries payable to FDIC		3
Provision for loan losses	401	589
Ending balance	5,112	4,171
Period-End Amount Allocated to:
Individually evaluated for impairment			165	6
Collectively evaluated for impairment			4,569	3,743
Acquired with deteriorated credit quality	5,486	4,186	5,112	4,171
Commercial, financial, agricultural | Receivables Acquired with Deteriorated Credit Quality
Rollforward of the allowance for loan losses
Ending balance	378	422
Period-End Amount Allocated to:
Acquired with deteriorated credit quality	378	422	378	422
Real estate – construction
Rollforward of the allowance for loan losses
Beginning balance	2,380	1,852
Charge-offs		0
Recoveries	31	6
Net (charge-offs) recoveries	31	6
Provision for loan losses		85
Benefit attributable to FDIC loss-share agreements		0
Recoveries payable to FDIC		0
Provision for loan losses	(292)	85
Ending balance	2,119	1,943
Period-End Amount Allocated to:
Individually evaluated for impairment			0	0
Collectively evaluated for impairment			2,119	1,943
Acquired with deteriorated credit quality	2,380	1,852	2,119	1,943
Real estate – construction | Receivables Acquired with Deteriorated Credit Quality
Rollforward of the allowance for loan losses
Ending balance	0	0
Period-End Amount Allocated to:
Acquired with deteriorated credit quality	0	0	0	0
Real estate – 1-4 family mortgage
Rollforward of the allowance for loan losses
Beginning balance	14,294	13,908
Charge-offs	(275)	(116)
Recoveries	82	395
Net (charge-offs) recoveries	(193)	279
Provision for loan losses		365
Benefit attributable to FDIC loss-share agreements		(37)
Recoveries payable to FDIC		27
Provision for loan losses	(1,939)	355
Ending balance	12,162	14,542
Period-End Amount Allocated to:
Individually evaluated for impairment			1,139	4,311
Collectively evaluated for impairment			10,256	9,896
Acquired with deteriorated credit quality	14,294	13,908	12,162	14,542
Real estate – 1-4 family mortgage | Receivables Acquired with Deteriorated Credit Quality
Rollforward of the allowance for loan losses
Ending balance	767	335
Period-End Amount Allocated to:
Acquired with deteriorated credit quality	767	335	767	335
Real estate – commercial mortgage
Rollforward of the allowance for loan losses
Beginning balance	19,059	21,111
Charge-offs	(227)	(1,001)
Recoveries	95	92
Net (charge-offs) recoveries	(132)	(909)
Provision for loan losses		530
Benefit attributable to FDIC loss-share agreements		(118)
Recoveries payable to FDIC		161
Provision for loan losses	3,146	573
Ending balance	22,073	20,775
Period-End Amount Allocated to:
Individually evaluated for impairment			2,670	3,082
Collectively evaluated for impairment			17,830	16,429
Acquired with deteriorated credit quality	19,059	21,111	22,073	20,775
Real estate – commercial mortgage | Receivables Acquired with Deteriorated Credit Quality
Rollforward of the allowance for loan losses
Ending balance	1,573	1,264
Period-End Amount Allocated to:
Acquired with deteriorated credit quality	1,573	1,264	1,573	1,264
Installment and other
Rollforward of the allowance for loan losses
Beginning balance	1,518	1,380
Charge-offs	(264)	(180)
Recoveries	19	30
Net (charge-offs) recoveries	(245)	(150)
Provision for loan losses		198
Benefit attributable to FDIC loss-share agreements		0
Recoveries payable to FDIC		0
Provision for loan losses	184	198
Ending balance	1,457	1,428
Period-End Amount Allocated to:
Individually evaluated for impairment			3	0
Collectively evaluated for impairment			1,453	1,427
Acquired with deteriorated credit quality	1,518	1,380	1,457	1,428
Installment and other | Receivables Acquired with Deteriorated Credit Quality
Rollforward of the allowance for loan losses
Ending balance	1	1
Period-End Amount Allocated to:
Acquired with deteriorated credit quality	$ 1	$ 1	$ 1	$ 1