Loans and Asset Quality Information (Details 8) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Provisions	$ 4,980	$ 7,073	$ 21,720	$ 35,095
Non-covered
Beginning balance	44,816	47,523	41,643	35,610	35,610
Charge-offs	(5,164)	(9,250)	(14,505)	(21,988)	(66,545)
Recoveries	336	911	3,036	1,811	2,585
Provisions	3,487	5,970	13,301	29,721	69,993
Ending balance	43,475	45,154	43,475	45,154	41,643
Ending balances: Allowance for loan losses
Individually evaluated for impairment	2,470	5,066	2,470	5,066	2,964
Collectively evaluated for impairment	41,005	40,088	41,005	40,088	38,679
Loans acquired with deteriorated credit quality
Loans receivable:
Ending balance - total	2,214,149	2,135,596	2,214,149	2,135,596	2,092,819
Ending balances: Loans
Individually evaluated for impairment	50,846	76,054	50,846	76,054	42,144
Collectively evaluated for impairment	2,163,303	2,059,542	2,163,303	2,059,542	2,050,675
Loans acquired with deteriorated credit quality
Commercial, financial and agricultural
Beginning balance	5,960	5,061	4,687	3,780	3,780
Charge-offs	(1,205)	(571)	(2,589)	(2,633)	(4,912)
Recoveries	28	219	261	253	354
Provisions	1,618	468	4,042	3,777	5,465
Ending balance	6,401	5,177	6,401	5,177	4,687
Ending balances: Allowance for loan losses
Individually evaluated for impairment	140	874	140	874	2
Collectively evaluated for impairment	6,261	4,303	6,261	4,303	4,685
Loans acquired with deteriorated credit quality
Loans receivable:
Ending balance - total	178,396	171,716	178,396	171,716	170,741
Ending balances: Loans
Individually evaluated for impairment	1,295	969	1,295	969	10
Collectively evaluated for impairment	177,101	170,747	177,101	170,747	170,731
Loans acquired with deteriorated credit quality
Real Estate construction, land development and other land loans
Beginning balance	14,593	17,819	12,856	11,306	11,306
Charge-offs	(800)	(4,628)	(2,017)	(7,480)	(19,312)
Recoveries	91	487	708	801	986
Provisions	(1,224)	1,109	1,113	10,160	19,876
Ending balance	12,660	14,787	12,660	14,787	12,856
Ending balances: Allowance for loan losses
Individually evaluated for impairment	329	908	329	908	504
Collectively evaluated for impairment	12,331	13,879	12,331	13,879	12,352
Loans acquired with deteriorated credit quality
Loans receivable:
Ending balance - total	232,670	236,960	232,670	236,960	218,108
Ending balances: Loans
Individually evaluated for impairment	8,069	17,078	8,069	17,078	5,949
Collectively evaluated for impairment	224,601	219,882	224,601	219,882	212,159
Loans acquired with deteriorated credit quality
Real estate residential, farmland and mutli-family
Beginning balance	14,961	14,959	14,082	13,532	13,532
Charge-offs	(893)	(1,399)	(2,548)	(5,635)	(20,879)
Recoveries	60	92	723	346	430
Provisions	671	1,731	2,542	7,140	20,999
Ending balance	14,799	15,383	14,799	15,383	14,082
Ending balances: Allowance for loan losses
Individually evaluated for impairment	1,298	1,911	1,298	1,911	1,419
Collectively evaluated for impairment	13,501	13,472	13,501	13,472	12,663
Loans acquired with deteriorated credit quality
Loans receivable:
Ending balance - total	859,330	826,953	859,330	826,953	819,439
Ending balances: Loans
Individually evaluated for impairment	19,903	25,454	19,903	25,454	18,618
Collectively evaluated for impairment	839,427	801,499	839,427	801,499	800,821
Loans acquired with deteriorated credit quality
Real estate home equity lines of credit
Beginning balance	2,061	2,146	1,884	1,690	1,690
Charge-offs	(200)	(1,098)	(1,089)	(1,830)	(3,287)
Recoveries	6	10	68	129	209
Provisions	193	825	1,197	1,894	3,272
Ending balance	2,060	1,883	2,060	1,883	1,884
Ending balances: Allowance for loan losses
Individually evaluated for impairment	1	1	1	1	3
Collectively evaluated for impairment	2,059	1,882	2,059	1,882	1,881
Loans acquired with deteriorated credit quality
Loans receivable:
Ending balance - total	197,697	203,154	197,697	203,154	200,880
Ending balances: Loans
Individually evaluated for impairment	22	299	22	299	43
Collectively evaluated for impairment	197,675	202,855	197,675	202,855	200,837
Loans acquired with deteriorated credit quality
Real estate mortgage commercial and other
Beginning balance	5,239	5,719	5,247	3,414	3,414
Charge-offs	(1,473)	(1,247)	(3,920)	(3,417)	(16,616)
Recoveries	27	21	909	68	333
Provisions	1,517	1,354	3,074	5,782	18,116
Ending balance	5,310	5,847	5,310	5,847	5,247
Ending balances: Allowance for loan losses
Individually evaluated for impairment	700	1,372	700	1,372	1,036
Collectively evaluated for impairment	4,610	4,475	4,610	4,475	4,211
Loans acquired with deteriorated credit quality
Loans receivable:
Ending balance - total	695,734	640,578	695,734	640,578	627,940
Ending balances: Loans
Individually evaluated for impairment	21,543	32,254	21,543	32,254	17,524
Collectively evaluated for impairment	674,191	608,324	674,191	608,324	610,416
Loans acquired with deteriorated credit quality
Consumer
Beginning balance	1,703	1,791	1,939	1,872	1,872
Charge-offs	(593)	(307)	(1,683)	(993)	(1,539)
Recoveries	124	82	367	214	273
Provisions	377	315	988	788	1,333
Ending balance	1,611	1,881	1,611	1,881	1,939
Ending balances: Allowance for loan losses
Individually evaluated for impairment	2		2
Collectively evaluated for impairment	1,609	1,881	1,609	1,881	1,939
Loans acquired with deteriorated credit quality
Loans receivable:
Ending balance - total	50,322	56,235	50,322	56,235	55,711
Ending balances: Loans
Individually evaluated for impairment	14		14
Collectively evaluated for impairment	50,308	56,235	50,308	56,235	55,711
Loans acquired with deteriorated credit quality
Unallocated
Beginning balance	299	28	948	16	16
Charge-offs			(659)
Recoveries
Provisions	335	168	345	180	932
Ending balance	634	196	634	196	948
Ending balances: Allowance for loan losses
Individually evaluated for impairment
Collectively evaluated for impairment	634	196	634	196	948
Loans acquired with deteriorated credit quality
Loans receivable:
Ending balance - total
Ending balances: Loans
Individually evaluated for impairment
Collectively evaluated for impairment
Loans acquired with deteriorated credit quality