ALLOWANCE FOR CREDIT LOSSES, SCHEDULE OF IMPAIRED FINANCING RECEIVABLE (Details) (USD $) In Thousands	Sep. 30, 2011	Dec. 31, 2010	Sep. 30, 2010	Dec. 31, 2009
Financing Receivable, Impaired [Line Items]
Recorded balance of impaired loans	$ 279,889	$ 273,405
Allowance for impaired loans and leases	38,657	40,719
Allowance for all other loans and leases	161,029	156,194
Total allowance	199,686	196,913	205,081	176,043
Commercial and industrial segment [Member]
Financing Receivable, Impaired [Line Items]
Recorded balance of impaired loans	6,001	2,136
Allowance for impaired loans and leases	757	125
Allowance for all other loans and leases	19,267	22,354
Total allowance	20,024	22,479	22,194	21,154
Consumer mortgages [Member] | Real estate segment [Member]
Financing Receivable, Impaired [Line Items]
Recorded balance of impaired loans	30,707	28,223
Allowance for impaired loans and leases	4,050	4,226
Allowance for all other loans and leases	35,451	31,314
Total allowance	39,501	35,540	34,505	37,048
Home equity [Member] | Real estate segment [Member]
Financing Receivable, Impaired [Line Items]
Recorded balance of impaired loans	1,526	851
Allowance for impaired loans and leases	228	41
Allowance for all other loans and leases	9,660	7,264
Total allowance	9,888	7,305	7,135	7,218
Agricultural [Member] | Real estate segment [Member]
Financing Receivable, Impaired [Line Items]
Recorded balance of impaired loans	4,217	4,295
Allowance for impaired loans and leases	463	544
Allowance for all other loans and leases	3,929	4,453
Total allowance	4,392	4,997	4,688	4,192
Commercial and industrial-owner occupied [Member] | Real estate segment [Member]
Financing Receivable, Impaired [Line Items]
Recorded balance of impaired loans	22,379	16,073
Allowance for impaired loans and leases	1,755	1,361
Allowance for all other loans and leases	19,715	19,042
Total allowance	21,470	20,403	22,729	22,989
Construction, acquisition and development [Member] | Real estate segment [Member]
Financing Receivable, Impaired [Line Items]
Recorded balance of impaired loans	168,001	184,918
Allowance for impaired loans and leases	24,911	29,195
Allowance for all other loans and leases	23,327	29,853
Total allowance	48,238	59,048	63,333	46,193
Commercial [Member] | Real estate segment [Member]
Financing Receivable, Impaired [Line Items]
Recorded balance of impaired loans	45,832	36,207
Allowance for impaired loans and leases	6,393	5,227
Allowance for all other loans and leases	33,170	28,212
Total allowance	39,563	33,439	33,325	26,694
Credit cards segment [Member]
Financing Receivable, Impaired [Line Items]
Recorded balance of impaired loans	0	0
Allowance for impaired loans and leases	0	0
Allowance for all other loans and leases	3,920	4,126
Total allowance	3,920	4,126	3,307	3,481
All other receivables [Member]
Financing Receivable, Impaired [Line Items]
Recorded balance of impaired loans	1,226	702
Allowance for impaired loans and leases	100	0
Allowance for all other loans and leases	12,590	9,576
Total allowance	$ 12,690	$ 9,576	$ 13,865	$ 7,074