Loans and the Allowance for Loan Losses (Details 10) (USD $) In Thousands, unless otherwise specified	3 Months Ended												12 Months Ended
	Dec. 31, 2013		Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013		Dec. 31, 2012		Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012		Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Rollforward of the allowance for loan losses
Beginning balance					$ 44,347						$ 44,340		$ 44,347		$ 44,340		$ 45,415
Charge-offs													(9,551)		(20,555)		(25,793)
Recoveries													2,519		2,437		2,368
Net charge-offs													(7,032)		(18,118)		(23,425)
Provision for loan losses													11,738		28,272		24,427
Benefit attributable to FDIC loss-share agreements													(2,361)		(10,408)		2,088
Recoveries payable to FDIC													973		261		11
Provision for loan losses charged to operations	2,000		2,300	3,000	3,050		4,000		4,625	4,700	4,800		10,350		18,125		22,350
Ending balance	47,665						44,347						47,665		44,347		44,340
Period-End Amount Allocated to:
Individually evaluated for impairment	14,650						17,597						14,650		17,597		15,410
Collectively evaluated for impairment	33,015						26,750						33,015		26,750		28,930
Acquired with deteriorated credit quality	0						0						0		0		0
Ending balance	47,665						44,347						47,665		44,347		44,340
Commercial, financial, agricultural
Rollforward of the allowance for loan losses
Beginning balance					3,307						4,197		3,307		4,197		2,625
Charge-offs													(1,184)		(4,923)		(2,037)
Recoveries													356		531		272
Net charge-offs													(828)		(4,392)		(1,765)
Provision for loan losses													982		4,274		3,464
Benefit attributable to FDIC loss-share agreements													(403)		(777)		132
Recoveries payable to FDIC													32		5		5
Provision for loan losses charged to operations													611		3,502		3,337
Ending balance	3,090						3,307						3,090		3,307		4,197
Period-End Amount Allocated to:
Individually evaluated for impairment	260						708						260		708		1,441
Collectively evaluated for impairment	2,830						2,599						2,830		2,599		2,756
Acquired with deteriorated credit quality	0						0						0		0		0
Ending balance	3,090						3,307						3,090		3,307		4,197
Real estate – construction
Rollforward of the allowance for loan losses
Beginning balance					711						1,073		711		1,073		2,115
Charge-offs													0		(187)		(836)
Recoveries													75		34		110
Net charge-offs													75		(153)		(726)
Provision for loan losses													304		(121)		(316)
Benefit attributable to FDIC loss-share agreements													0		(88)		0
Recoveries payable to FDIC													1		0		0
Provision for loan losses charged to operations													305		(209)		(316)
Ending balance	1,091						711						1,091		711		1,073
Period-End Amount Allocated to:
Individually evaluated for impairment	0						0						0		0		16
Collectively evaluated for impairment	1,091						711						1,091		711		1,057
Acquired with deteriorated credit quality	0						0						0		0		0
Ending balance	1,091						711						1,091		711		1,073
Real estate – 1-4 family mortgage
Rollforward of the allowance for loan losses
Beginning balance					18,347						17,191		18,347		17,191		20,870
Charge-offs													(3,093)		(9,231)		(16,755)
Recoveries													1,044		1,330		767
Net charge-offs													(2,049)		(7,901)		(15,988)
Provision for loan losses													2,496		13,201		12,900
Benefit attributable to FDIC loss-share agreements													(1,039)		(4,326)		597
Recoveries payable to FDIC													874		182		6
Provision for loan losses charged to operations													2,331		9,057		12,309
Ending balance	18,629						18,347						18,629		18,347		17,191
Period-End Amount Allocated to:
Individually evaluated for impairment	7,353						9,201						7,353		9,201		6,077
Collectively evaluated for impairment	11,276						9,146						11,276		9,146		11,114
Acquired with deteriorated credit quality	0						0						0		0		0
Ending balance	18,629						18,347						18,629		18,347		17,191
Real estate – commercial mortgage
Rollforward of the allowance for loan losses
Beginning balance					21,416						20,979		21,416		20,979		18,779
Charge-offs													(4,782)		(5,828)		(5,792)
Recoveries													980		455		1,056
Net charge-offs													(3,802)		(5,373)		(4,736)
Provision for loan losses													6,927		10,938		8,289
Benefit attributable to FDIC loss-share agreements													(919)		(5,202)		1,353
Recoveries payable to FDIC													66		74		0
Provision for loan losses charged to operations													6,074		5,810		6,936
Ending balance	23,688						21,416						23,688		21,416		20,979
Period-End Amount Allocated to:
Individually evaluated for impairment	7,036						7,688						7,036		7,688		7,876
Collectively evaluated for impairment	16,652						13,728						16,652		13,728		13,103
Acquired with deteriorated credit quality	0						0						0		0		0
Ending balance	23,688						21,416						23,688		21,416		20,979
Installment loans to individuals
Rollforward of the allowance for loan losses
Beginning balance					566	[1]					900	[1]	566	[1]	900	[1]	1,026
Charge-offs													(492)	[1]	(386)	[1]	(373)	[1]
Recoveries													64	[1]	87	[1]	163	[1]
Net charge-offs													(428)	[1]	(299)	[1]	(210)	[1]
Provision for loan losses													1,029	[1]	(20)	[1]	90	[1]
Benefit attributable to FDIC loss-share agreements													0	[1]	(15)	[1]	6	[1]
Recoveries payable to FDIC													0	[1]	0	[1]	0	[1]
Provision for loan losses charged to operations													1,029	[1]	(35)	[1]	84	[1]
Ending balance	1,167	[1]					566	[1]					1,167	[1]	566	[1]	900	[1]
Period-End Amount Allocated to:
Individually evaluated for impairment	1	[1]					0	[1]					1	[1]	0	[1]	0	[1]
Collectively evaluated for impairment	1,166	[1]					566	[1]					1,166	[1]	566	[1]	900	[1]
Acquired with deteriorated credit quality	0	[1]					0	[1]					0	[1]	0	[1]	0	[1]
Ending balance	$ 1,167	[1]					$ 566	[1]					$ 1,167	[1]	$ 566	[1]	$ 900	[1]

[1] Includes lease financing receivables.