Loans and the Allowance for Loan Losses (Details 11) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Allowance for loan losses:
Beginning balance	$ 44,779	$ 47,571	$ 44,340	$ 45,415
Charge-offs	(6,170)	(4,968)	(16,022)	(15,128)
Recoveries	835	429	1,626	1,895
Net charge-offs	(5,335)	(4,539)	(14,396)	(13,233)
Provision for loan losses	5,967	5,758	20,905	16,608
Benefit attributable to FDIC loss-share agreements	(1,582)	(258)	(7,753)	(258)
Recoveries payable to FDIC	240		973
Provision for loan losses charged to operations	4,625	5,500	14,125	16,350
Ending balance	44,069	48,532	44,069	48,532
Period-End Amount Allocated to:
Individually evaluated for impairment	19,169	19,717	19,169	19,717
Collectively evaluated for impairment	24,900	28,815	24,900	28,815
Acquired with deteriorated credit quality
Ending balance	44,069	48,532	44,069	48,532
Commercial [Member]
Allowance for loan losses:
Beginning balance	3,235	3,841	4,197	2,625
Charge-offs	(2,590)	(210)	(4,623)	(1,494)
Recoveries	145	61	323	239
Net charge-offs	(2,445)	(149)	(4,300)	(1,255)
Provision for loan losses	2,795	174	4,052	2,496
Benefit attributable to FDIC loss-share agreements	(335)	(40)	(723)	(40)
Recoveries payable to FDIC	2		26
Provision for loan losses charged to operations	2,462	134	3,355	2,456
Ending balance	3,252	3,826	3,252	3,826
Period-End Amount Allocated to:
Individually evaluated for impairment	715	1,074	715	1,074
Collectively evaluated for impairment	2,537	2,752	2,537	2,752
Acquired with deteriorated credit quality
Ending balance	3,252	3,826	3,252	3,826
Real Estate - Construction [Member]
Allowance for loan losses:
Beginning balance	966	1,389	1,073	2,115
Charge-offs			(42)	(798)
Recoveries	3	18	6	49
Net charge-offs	3	18	(36)	(749)
Provision for loan losses	79	(240)	28	(199)
Benefit attributable to FDIC loss-share agreements			(17)
Recoveries payable to FDIC
Provision for loan losses charged to operations	79	(240)	11	(199)
Ending balance	1,048	1,167	1,048	1,167
Period-End Amount Allocated to:
Individually evaluated for impairment	2	16	2	16
Collectively evaluated for impairment	1,046	1,151	1,046	1,151
Acquired with deteriorated credit quality
Ending balance	1,048	1,167	1,048	1,167
Real Estate - 1-4 Family Mortgage [Member]
Allowance for loan losses:
Beginning balance	18,980	19,864	17,191	20,870
Charge-offs	(2,682)	(3,281)	(7,230)	(9,896)
Recoveries	648	245	981	582
Net charge-offs	(2,034)	(3,039)	(6,249)	(9,314)
Provision for loan losses	2,269	4,298	10,269	9,570
Benefit attributable to FDIC loss-share agreements	(1,187)		(3,421)
Recoveries payable to FDIC	162		400
Provision for loan losses charged to operations	1,244	4,298	7,248	9,570
Ending balance	18,190	21,126	18,190	21,126
Period-End Amount Allocated to:
Individually evaluated for impairment	10,011	9,915	10,011	9,915
Collectively evaluated for impairment	8,179	11,211	8,179	11,211
Acquired with deteriorated credit quality
Ending balance	18,190	21,126	18,190	21,126
Real estate - commercial mortgage [Member]
Allowance for loan losses:
Beginning balance	20,765	21,518	20,979	18,779
Charge-offs	(780)	(1,372)	(3,806)	(2,746)
Recoveries	22	17	247	886
Net charge-offs	(758)	(1,355)	(3,559)	(1,860)
Provision for loan losses	988	1,536	6,640	4,780
Benefit attributable to FDIC loss-share agreements	(60)	(218)	(3,592)	(218)
Recoveries payable to FDIC	76		543
Provision for loan losses charged to operations	1,004	1,318	3,591	4,562
Ending balance	21,011	21,481	21,011	21,481
Period-End Amount Allocated to:
Individually evaluated for impairment	8,441	8,712	8,441	8,712
Collectively evaluated for impairment	12,570	12,769	12,570	12,769
Acquired with deteriorated credit quality
Ending balance	21,011	21,481	21,011	21,481
Installment and Other [Member]
Allowance for loan losses:
Beginning balance	833	956	900	1,026
Charge-offs	(118)	(105)	(321)	(194)
Recoveries	17	88	69	139
Net charge-offs	(101)	(17)	(252)	(55)
Provision for loan losses	(164)	(10)	(84)	(39)
Benefit attributable to FDIC loss-share agreements
Recoveries payable to FDIC			4
Provision for loan losses charged to operations	(164)	(10)	(80)	(39)
Ending balance	568	932	568	932
Period-End Amount Allocated to:
Individually evaluated for impairment
Collectively evaluated for impairment	586	932	586	932
Acquired with deteriorated credit quality
Ending balance	$ 568	$ 932	$ 568	$ 932