ALLOWANCE FOR CREDIT LOSSES, SCHEDULE OF IMPAIRED FINANCING RECEIVABLE (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008
Financing Receivable, Impaired [Line Items]
Recorded balance of impaired loans	$ 234,923	$ 273,405
Allowance for impaired loans and leases	39,708	40,719
Allowance for all other loans and leases	155,410	156,194
Total allowance	195,118	196,913	176,043	132,793
Commercial and industrial segment [Member]
Financing Receivable, Impaired [Line Items]
Recorded balance of impaired loans	7,833	2,136
Allowance for impaired loans and leases	4,071	125
Allowance for all other loans and leases	16,653	22,354
Total allowance	20,724	22,479	21,154
Real estate segment [Member] | Consumer mortgages [Member]
Financing Receivable, Impaired [Line Items]
Recorded balance of impaired loans	31,793	28,223
Allowance for impaired loans and leases	4,386	4,226
Allowance for all other loans and leases	32,143	31,314
Total allowance	36,529	35,540	37,048
Real estate segment [Member] | Home equity [Member]
Financing Receivable, Impaired [Line Items]
Recorded balance of impaired loans	675	851
Allowance for impaired loans and leases	48	41
Allowance for all other loans and leases	8,582	7,264
Total allowance	8,630	7,305	7,218
Real estate segment [Member] | Agricultural [Member]
Financing Receivable, Impaired [Line Items]
Recorded balance of impaired loans	3,096	4,295
Allowance for impaired loans and leases	380	544
Allowance for all other loans and leases	3,541	4,453
Total allowance	3,921	4,997	4,192
Real estate segment [Member] | Commercial and industrial-owner occupied [Member]
Financing Receivable, Impaired [Line Items]
Recorded balance of impaired loans	24,801	16,073
Allowance for impaired loans and leases	3,601	1,361
Allowance for all other loans and leases	18,328	19,042
Total allowance	21,929	20,403	22,989
Real estate segment [Member] | Construction, acquisition and development [Member]
Financing Receivable, Impaired [Line Items]
Recorded balance of impaired loans	128,179	184,918
Allowance for impaired loans and leases	21,581	29,195
Allowance for all other loans and leases	23,981	29,853
Total allowance	45,562	59,048	46,193
Real estate segment [Member] | Commercial [Member]
Financing Receivable, Impaired [Line Items]
Recorded balance of impaired loans	36,122	36,207
Allowance for impaired loans and leases	5,324	5,227
Allowance for all other loans and leases	34,120	28,212
Total allowance	39,444	33,439	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	4,021	4,126
Total allowance	4,021	4,126	3,481
All other receivables [Member]
Financing Receivable, Impaired [Line Items]
Recorded balance of impaired loans	2,424	702
Allowance for impaired loans and leases	317	0
Allowance for all other loans and leases	14,041	9,576
Total allowance	$ 14,358	$ 9,576	$ 7,074