Loans and the Allowance for Loan Losses (Details 11) (USD $) In Thousands, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2014		Sep. 30, 2013		Sep. 30, 2014		Sep. 30, 2013
Allowance for loan losses:
Beginning balance	$ 47,304		$ 47,034		$ 47,665		$ 44,347
Charge-offs	(6,102)		(3,326)		(9,928)		(8,344)
Recoveries	1,150		242		1,715		1,897
Net (charge-offs) recoveries	(4,952)		(3,084)		(8,213)		(6,447)
Provision for loan losses	4,775		2,768		8,641		9,652
Benefit attributable to FDIC loss-share agreements	(3,377)		(522)		(5,051)		(2,193)
Recoveries payable to FDIC	819		54		1,527		891
Provision for loan losses charged to operations	2,217		2,300		5,117		8,350
Ending balance	44,569		46,250		44,569		46,250
Period-End Amount Allocated to:
Individually evaluated for impairment	8,080		14,908		8,080		14,908
Collectively evaluated for impairment	36,489		31,342		36,489		31,342
Acquired with deteriorated credit quality	0		0		0		0
Ending balance	44,569		46,250		44,569		46,250
Commercial, financial, agricultural
Allowance for loan losses:
Beginning balance	3,264		3,478		3,090		3,307
Charge-offs	(1,206)		(887)		(1,325)		(1,167)
Recoveries	103		54		215		301
Net (charge-offs) recoveries	(1,103)		(833)		(1,110)		(866)
Provision for loan losses	1,007		364		1,095		874
Benefit attributable to FDIC loss-share agreements	(19)		(67)		(87)		(397)
Recoveries payable to FDIC	22		5		183		29
Provision for loan losses charged to operations	1,010		302		1,191		506
Ending balance	3,171		2,947		3,171		2,947
Period-End Amount Allocated to:
Individually evaluated for impairment	0		260		0		260
Collectively evaluated for impairment	3,171		2,687		3,171		2,687
Acquired with deteriorated credit quality	0		0		0		0
Ending balance	3,171		2,947		3,171		2,947
Real estate – construction
Allowance for loan losses:
Beginning balance	1,267		863		1,091		711
Charge-offs	0		0		0		0
Recoveries	6		7		14		70
Net (charge-offs) recoveries	6		7		14		70
Provision for loan losses	109		44		276		132
Benefit attributable to FDIC loss-share agreements	0		0		0		0
Recoveries payable to FDIC	0		0		1		1
Provision for loan losses charged to operations	109		44		277		133
Ending balance	1,382		914		1,382		914
Period-End Amount Allocated to:
Individually evaluated for impairment	0		0		0		0
Collectively evaluated for impairment	1,382		914		1,382		914
Acquired with deteriorated credit quality	0		0		0		0
Ending balance	1,382		914		1,382		914
Real estate – 1-4 family mortgage
Allowance for loan losses:
Beginning balance	11,797		19,432		18,629		18,347
Charge-offs	(1,271)		(1,251)		(4,143)		(2,517)
Recoveries	751		120		1,108		591
Net (charge-offs) recoveries	(520)		(1,131)		(3,035)		(1,926)
Provision for loan losses	(491)		370		(5,182)		2,088
Benefit attributable to FDIC loss-share agreements	(189)		(326)		(324)		(956)
Recoveries payable to FDIC	16		45		525		837
Provision for loan losses charged to operations	(664)		89		(4,981)		1,969
Ending balance	10,613		18,390		10,613		18,390
Period-End Amount Allocated to:
Individually evaluated for impairment	1,260		7,569		1,260		7,569
Collectively evaluated for impairment	9,353		10,821		9,353		10,821
Acquired with deteriorated credit quality	0		0		0		0
Ending balance	10,613		18,390		10,613		18,390
Real estate – commercial mortgage
Allowance for loan losses:
Beginning balance	29,771		22,239		23,688		21,416
Charge-offs	(3,513)		(1,107)		(4,056)		(4,226)
Recoveries	267		38		325		885
Net (charge-offs) recoveries	(3,246)		(1,069)		(3,731)		(3,341)
Provision for loan losses	4,043		1,976		12,045		5,762
Benefit attributable to FDIC loss-share agreements	(3,169)		(129)		(4,640)		(840)
Recoveries payable to FDIC	781		4		818		24
Provision for loan losses charged to operations	1,655		1,851		8,223		4,946
Ending balance	28,180		23,021		28,180		23,021
Period-End Amount Allocated to:
Individually evaluated for impairment	6,820		7,079		6,820		7,079
Collectively evaluated for impairment	21,360		15,942		21,360		15,942
Acquired with deteriorated credit quality	0		0		0		0
Ending balance	28,180		23,021		28,180		23,021
Installment loans to individuals
Allowance for loan losses:
Beginning balance	1,205	[1]	1,022	[1]	1,167	[1]	566	[1]
Charge-offs	(112)	[1]	(81)	[1]	(404)	[1]	(434)	[1]
Recoveries	23	[1]	23	[1]	53	[1]	50	[1]
Net (charge-offs) recoveries	(89)	[1]	(58)	[1]	(351)	[1]	(384)	[1]
Provision for loan losses	107	[1]	14	[1]	407	[1]	796	[1]
Benefit attributable to FDIC loss-share agreements	0	[1]	0	[1]	0	[1]	0	[1]
Recoveries payable to FDIC	0	[1]	0	[1]	0	[1]	0	[1]
Provision for loan losses charged to operations	107	[1]	14	[1]	407	[1]	796	[1]
Ending balance	1,223	[1]	978	[1]	1,223	[1]	978	[1]
Period-End Amount Allocated to:
Individually evaluated for impairment	0	[1]	0	[1]	0	[1]	0	[1]
Collectively evaluated for impairment	1,223	[1]	978	[1]	1,223	[1]	978	[1]
Acquired with deteriorated credit quality	0	[1]	0	[1]	0	[1]	0	[1]
Ending balance	$ 1,223	[1]	$ 978	[1]	$ 1,223	[1]	$ 978	[1]

[1] Includes lease financing receivables.