Loans and the Allowance for Loan Losses - (Details 11) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2016	Mar. 31, 2015
Allowance for loan losses:
Beginning balance		$ 42,437	$ 42,289
Charge-offs		(1,954)	(1,403)
Recoveries		576	341
Net (charge-offs) recoveries		(1,378)	(1,062)
Provision for loan losses		1,779	732
Benefit attributable to FDIC loss-share agreements		(170)	(126)
Recoveries payable to FDIC		191	469
Provision for loan losses charged to operations		1,800	1,075
Ending balance		42,859	42,302
Period-End Amount Allocated to:
Individually evaluated for impairment				$ 7,399	$ 6,520
Collectively evaluated for impairment				33,438	33,193
Acquired with deteriorated credit quality		42,437	42,289	42,859	42,302
Commercial, financial, agricultural
Allowance for loan losses:
Beginning balance		4,186	3,305
Charge-offs		(657)	(235)
Recoveries		53	35
Net (charge-offs) recoveries		(604)	(200)
Provision for loan losses		601	1,027
Benefit attributable to FDIC loss-share agreements		(15)	(25)
Recoveries payable to FDIC		3	2
Provision for loan losses charged to operations		589	1,004
Ending balance		4,171	4,109
Period-End Amount Allocated to:
Individually evaluated for impairment				6	0
Collectively evaluated for impairment				3,743	2,911
Acquired with deteriorated credit quality		4,186	3,305	4,171	4,109
Real estate – construction
Allowance for loan losses:
Beginning balance		1,852	1,415
Charge-offs		0	0
Recoveries		6	6
Net (charge-offs) recoveries		6	6
Provision for loan losses		85	(63)
Benefit attributable to FDIC loss-share agreements		0	0
Recoveries payable to FDIC		0	1
Provision for loan losses charged to operations		85	(62)
Ending balance		1,943	1,359
Period-End Amount Allocated to:
Individually evaluated for impairment				0	0
Collectively evaluated for impairment				1,943	1,359
Acquired with deteriorated credit quality		1,852	1,415	1,943	1,359
Real estate – 1-4 family mortgage
Allowance for loan losses:
Beginning balance		13,908	13,549
Charge-offs		(116)	(485)
Recoveries		395	155
Net (charge-offs) recoveries		279	(330)
Provision for loan losses		365	618
Benefit attributable to FDIC loss-share agreements		(37)	0
Recoveries payable to FDIC		27	208
Provision for loan losses charged to operations		355	826
Ending balance		14,542	14,045
Period-End Amount Allocated to:
Individually evaluated for impairment				4,311	4,227
Collectively evaluated for impairment				9,896	9,541
Acquired with deteriorated credit quality		13,908	13,549	14,542	14,045
Real estate – commercial mortgage
Allowance for loan losses:
Beginning balance		21,111	22,759
Charge-offs		(1,001)	(633)
Recoveries		92	112
Net (charge-offs) recoveries		(909)	(521)
Provision for loan losses		530	(887)
Benefit attributable to FDIC loss-share agreements		(118)	(101)
Recoveries payable to FDIC		161	258
Provision for loan losses charged to operations		573	(730)
Ending balance		20,775	21,508
Period-End Amount Allocated to:
Individually evaluated for impairment				3,082	2,293
Collectively evaluated for impairment				16,429	18,102
Acquired with deteriorated credit quality		21,111	22,759	20,775	21,508
Installment loans to individuals
Allowance for loan losses:
Beginning balance	[1]	1,380	1,261
Charge-offs	[1]	(180)	(50)
Recoveries	[1]	30	33
Net (charge-offs) recoveries	[1]	(150)	(17)
Provision for loan losses	[1]	198	37
Benefit attributable to FDIC loss-share agreements	[1]	0	0
Recoveries payable to FDIC	[1]	0	0
Provision for loan losses charged to operations	[1]	198	37
Ending balance	[1]	1,428	1,281
Period-End Amount Allocated to:
Individually evaluated for impairment	[1]			0	0
Collectively evaluated for impairment	[1]			1,427	1,280
Acquired with deteriorated credit quality	[1]	1,380	1,261	1,428	1,281
Receivables Acquired with Deteriorated Credit Quality
Allowance for loan losses:
Ending balance		2,022	2,589
Period-End Amount Allocated to:
Acquired with deteriorated credit quality		2,022	2,589	2,022	2,589
Receivables Acquired with Deteriorated Credit Quality | Commercial, financial, agricultural
Allowance for loan losses:
Ending balance		422	1,198
Period-End Amount Allocated to:
Acquired with deteriorated credit quality		422	1,198	422	1,198
Receivables Acquired with Deteriorated Credit Quality | Real estate – construction
Allowance for loan losses:
Ending balance		0	0
Period-End Amount Allocated to:
Acquired with deteriorated credit quality		0	0	0	0
Receivables Acquired with Deteriorated Credit Quality | Real estate – 1-4 family mortgage
Allowance for loan losses:
Ending balance		335	277
Period-End Amount Allocated to:
Acquired with deteriorated credit quality		335	277	335	277
Receivables Acquired with Deteriorated Credit Quality | Real estate – commercial mortgage
Allowance for loan losses:
Ending balance		1,264	1,113
Period-End Amount Allocated to:
Acquired with deteriorated credit quality		1,264	1,113	1,264	1,113
Receivables Acquired with Deteriorated Credit Quality | Installment loans to individuals
Allowance for loan losses:
Ending balance	[1]	1	1
Period-End Amount Allocated to:
Acquired with deteriorated credit quality	[1]	$ 1	$ 1	$ 1	$ 1

[1] Includes lease financing receivables.