Loans (Summary Of Impaired Financial Receivables (Analysis Of Covered Impaired Loans)) (Detail) (USD $) In Thousands, unless otherwise specified	9 Months Ended		12 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2011
Non-Covered Loans
Unpaid Contractual Principal Balance	$ 79,403	$ 95,926	$ 106,538
Recorded Investment With No Allowance
Recorded Investment With Allowance	58,118	75,658	88,774
Total impaired loans	58,118	75,658	88,774
Related Allowance	7,681	17,010	18,478
Average Recorded Investment	73,353	88,207	88,320
Non-Covered Loans | Commercial, financial & agricultural
Unpaid Contractual Principal Balance	8,261	8,895	9,592
Recorded Investment With No Allowance
Recorded Investment With Allowance	5,089	4,571	5,110
Total impaired loans	5,089	4,571	5,110
Related Allowance	876	1,277	1,366
Average Recorded Investment	4,974	5,848	5,700
Non-Covered Loans | Real estate - construction & development
Unpaid Contractual Principal Balance	19,583	26,450	21,893
Recorded Investment With No Allowance
Recorded Investment With Allowance	9,682	17,486	15,672
Total impaired loans	9,682	17,486	15,672
Related Allowance	1,253	6,164	4,053
Average Recorded Investment	11,879	19,417	18,667
Non-Covered Loans | Real estate - commercial and farmland
Unpaid Contractual Principal Balance	25,346	35,835	48,688
Recorded Investment With No Allowance
Recorded Investment With Allowance	20,948	31,455	45,006
Total impaired loans	20,948	31,455	45,006
Related Allowance	2,907	4,470	8,331
Average Recorded Investment	33,070	41,488	42,192
Non-Covered Loans | Real estate - residential
Unpaid Contractual Principal Balance	24,993	23,871	25,309
Recorded Investment With No Allowance
Recorded Investment With Allowance	21,304	21,436	22,053
Total impaired loans	21,304	21,436	22,053
Related Allowance	2,616	4,933	4,499
Average Recorded Investment	22,303	20,837	21,081
Non-Covered Loans | Consumer installment loans
Unpaid Contractual Principal Balance	1,220	875	1,056
Recorded Investment With No Allowance
Recorded Investment With Allowance	1,095	710	933
Total impaired loans	1,095	710	933
Related Allowance	29	166	229
Average Recorded Investment	1,127	617	680
Covered Loan
Unpaid Contractual Principal Balance	206,439	340,109	244,344
Recorded Investment With No Allowance	149,827	155,019	179,883
Recorded Investment With Allowance
Total impaired loans	149,827	155,019	179,883
Related Allowance
Average Recorded Investment	171,055	128,717	138,950
Covered Loan | Commercial, financial & agricultural
Unpaid Contractual Principal Balance	17,833	19,904	21,352
Recorded Investment With No Allowance	11,976	12,194	12,027
Recorded Investment With Allowance
Total impaired loans	11,976	12,194	12,027
Related Allowance
Average Recorded Investment	12,932	9,756	10,210
Covered Loan | Real estate - construction & development
Unpaid Contractual Principal Balance	34,787	111,148	47,005
Recorded Investment With No Allowance	23,833	33,380	34,363
Recorded Investment With Allowance
Total impaired loans	23,833	33,380	34,363
Related Allowance
Average Recorded Investment	31,653	29,672	30,610
Covered Loan | Real estate - commercial and farmland
Unpaid Contractual Principal Balance	98,909	135,514	106,953
Recorded Investment With No Allowance	72,802	65,592	84,740
Recorded Investment With Allowance
Total impaired loans	72,802	65,592	84,740
Related Allowance
Average Recorded Investment	82,430	49,573	56,607
Covered Loan | Real estate - residential
Unpaid Contractual Principal Balance	54,020	72,962	68,411
Recorded Investment With No Allowance	40,790	43,402	48,280
Recorded Investment With Allowance
Total impaired loans	40,790	43,402	48,280
Related Allowance
Average Recorded Investment	43,492	38,775	40,675
Covered Loan | Consumer installment loans
Unpaid Contractual Principal Balance	890	581	623
Recorded Investment With No Allowance	426	451	473
Recorded Investment With Allowance
Total impaired loans	426	451	473
Related Allowance
Average Recorded Investment	$ 548	$ 941	$ 848