Loans and the Allowance for Loan Losses - (Details 11) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Allowance for loan losses:
Beginning balance		$ 41,888	$ 47,304	$ 42,289	$ 47,665
Charge-offs		(956)	(6,102)	(4,657)	(9,928)
Recoveries		369	1,150	1,419	1,715
Net charge-offs		(587)	(4,952)	(3,238)	(8,213)
Provision for loan losses		629	4,775	2,200	8,641
Benefit attributable to FDIC loss-share agreements		(280)	(3,377)	(864)	(5,051)
Recoveries payable to FDIC		401	819	1,664	1,527
Provision for loan losses charged to operations		750	2,217	3,000	5,117
Ending balance		42,051	44,569	42,051	44,569
Period-End Amount Allocated to:
Individually evaluated for impairment						$ 7,797	$ 8,080
Collectively evaluated for impairment						32,304	36,489
Acquired with deteriorated credit quality		41,888	47,304	42,289	47,665	42,051	44,569
Commercial, financial, agricultural
Allowance for loan losses:
Beginning balance		3,971	3,264	3,305	3,090
Charge-offs		(143)	(1,206)	(501)	(1,325)
Recoveries		82	103	221	215
Net charge-offs		(61)	(1,103)	(280)	(1,110)
Provision for loan losses		(307)	1,007	624	1,095
Benefit attributable to FDIC loss-share agreements		(10)	(19)	(65)	(87)
Recoveries payable to FDIC		20	22	29	183
Provision for loan losses charged to operations		(297)	1,010	588	1,191
Ending balance		3,613	3,171	3,613	3,171
Period-End Amount Allocated to:
Individually evaluated for impairment						214	0
Collectively evaluated for impairment						3,014	3,171
Acquired with deteriorated credit quality		3,971	3,264	3,305	3,090	3,613	3,171
Real estate – construction
Allowance for loan losses:
Beginning balance		1,297	1,267	1,415	1,091
Charge-offs		0	0	(26)	0
Recoveries		3	6	16	14
Net charge-offs		3	6	(10)	14
Provision for loan losses		360	109	254	276
Benefit attributable to FDIC loss-share agreements		0	0	0	0
Recoveries payable to FDIC		1	0	2	1
Provision for loan losses charged to operations		361	109	256	277
Ending balance		1,661	1,382	1,661	1,382
Period-End Amount Allocated to:
Individually evaluated for impairment						0	0
Collectively evaluated for impairment						1,661	1,382
Acquired with deteriorated credit quality		1,297	1,267	1,415	1,091	1,661	1,382
Real estate – 1-4 family mortgage
Allowance for loan losses:
Beginning balance		13,792	11,797	13,549	18,629
Charge-offs		(251)	(1,271)	(1,605)	(4,143)
Recoveries		145	751	515	1,108
Net charge-offs		(106)	(520)	(1,090)	(3,035)
Provision for loan losses		165	(491)	653	(5,182)
Benefit attributable to FDIC loss-share agreements		(39)	(189)	(82)	(324)
Recoveries payable to FDIC		99	16	881	525
Provision for loan losses charged to operations		225	(664)	1,452	(4,981)
Ending balance		13,911	10,613	13,911	10,613
Period-End Amount Allocated to:
Individually evaluated for impairment						4,482	1,260
Collectively evaluated for impairment						9,137	9,353
Acquired with deteriorated credit quality		13,792	11,797	13,549	18,629	13,911	10,613
Real estate – commercial mortgage
Allowance for loan losses:
Beginning balance		21,547	29,771	22,759	23,688
Charge-offs		(430)	(3,513)	(2,287)	(4,056)
Recoveries		112	267	581	325
Net charge-offs		(318)	(3,246)	(1,706)	(3,731)
Provision for loan losses		53	4,043	244	12,045
Benefit attributable to FDIC loss-share agreements		(231)	(3,169)	(717)	(4,640)
Recoveries payable to FDIC		277	781	748	818
Provision for loan losses charged to operations		99	1,655	275	8,223
Ending balance		21,328	28,180	21,328	28,180
Period-End Amount Allocated to:
Individually evaluated for impairment						3,101	6,820
Collectively evaluated for impairment						16,955	21,360
Acquired with deteriorated credit quality		21,547	29,771	22,759	23,688	21,328	28,180
Installment loans to individuals
Allowance for loan losses:
Beginning balance	[1]	1,281	1,205	1,261	1,167
Charge-offs	[1]	(132)	(112)	(238)	(404)
Recoveries	[1]	27	23	86	53
Net charge-offs	[1]	(105)	(89)	(152)	(351)
Provision for loan losses	[1]	358	107	425	407
Benefit attributable to FDIC loss-share agreements	[1]	0	0	0	0
Recoveries payable to FDIC	[1]	4	0	4	0
Provision for loan losses charged to operations	[1]	362	107	429	407
Ending balance	[1]	1,538	1,223	1,538	1,223
Period-End Amount Allocated to:
Individually evaluated for impairment	[1]					0	0
Collectively evaluated for impairment	[1]					1,537	1,223
Acquired with deteriorated credit quality	[1]	1,281	1,205	1,261	1,167	1,538	1,223
Receivables Acquired with Deteriorated Credit Quality
Allowance for loan losses:
Ending balance		1,950	0	1,950	0
Period-End Amount Allocated to:
Acquired with deteriorated credit quality		1,950	0	1,950	0	1,950	0
Receivables Acquired with Deteriorated Credit Quality | Commercial, financial, agricultural
Allowance for loan losses:
Ending balance		385	0	385	0
Period-End Amount Allocated to:
Acquired with deteriorated credit quality		385	0	385	0	385	0
Receivables Acquired with Deteriorated Credit Quality | Real estate – construction
Allowance for loan losses:
Ending balance		0	0	0	0
Period-End Amount Allocated to:
Acquired with deteriorated credit quality		0	0	0	0	0	0
Receivables Acquired with Deteriorated Credit Quality | Real estate – 1-4 family mortgage
Allowance for loan losses:
Ending balance		292	0	292	0
Period-End Amount Allocated to:
Acquired with deteriorated credit quality		292	0	292	0	292	0
Receivables Acquired with Deteriorated Credit Quality | Real estate – commercial mortgage
Allowance for loan losses:
Ending balance		1,272	0	1,272	0
Period-End Amount Allocated to:
Acquired with deteriorated credit quality		1,272	0	1,272	0	1,272	0
Receivables Acquired with Deteriorated Credit Quality | Installment loans to individuals
Allowance for loan losses:
Ending balance	[1]	1	0	1	0
Period-End Amount Allocated to:
Acquired with deteriorated credit quality	[1]	$ 1	$ 0	$ 1	$ 0	$ 1	$ 0

[1] Includes lease financing receivables.