ALLOWANCE FOR CREDIT LOSSES, SCHEDULE OF IMPAIRED FINANCING RECEIVABLE (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011	Mar. 31, 2011	Dec. 31, 2010
Financing Receivable, Impaired [Line Items]
Recorded balance of impaired loans	$ 211,112	$ 234,923
Allowance for impaired loans and leases	25,546	39,708
Allowance for all other loans and leases	156,231	155,410
Total allowance	181,777	195,118	198,333	196,913
Consumer mortgages [Member]
Financing Receivable, Impaired [Line Items]
Total allowance			33,612	35,540
Home equity [Member]
Financing Receivable, Impaired [Line Items]
Total allowance			7,692	7,305
Agricultural [Member]
Financing Receivable, Impaired [Line Items]
Total allowance			4,447	4,997
Commercial and industrial-owner occupied [Member]
Financing Receivable, Impaired [Line Items]
Total allowance			29,924	20,403
Construction, acquisition and development [Member]
Financing Receivable, Impaired [Line Items]
Total allowance			54,228	59,048
Commercial [Member]
Financing Receivable, Impaired [Line Items]
Total allowance			33,485	33,439
Commercial and industrial segment [Member]
Financing Receivable, Impaired [Line Items]
Recorded balance of impaired loans	6,106	7,833
Allowance for impaired loans and leases	1,548	4,071
Allowance for all other loans and leases	19,434	16,653
Total allowance	20,982	20,724	20,379	22,479
Real estate segment [Member] | Consumer mortgages [Member]
Financing Receivable, Impaired [Line Items]
Recorded balance of impaired loans	28,416	31,793
Allowance for impaired loans and leases	3,977	4,386
Allowance for all other loans and leases	32,571	32,143
Total allowance	36,548	36,529		35,540
Real estate segment [Member] | Home equity [Member]
Financing Receivable, Impaired [Line Items]
Recorded balance of impaired loans	1,583	675
Allowance for impaired loans and leases	178	48
Allowance for all other loans and leases	8,050	8,582
Total allowance	8,228	8,630		7,305
Real estate segment [Member] | Agricultural [Member]
Financing Receivable, Impaired [Line Items]
Recorded balance of impaired loans	3,099	3,096
Allowance for impaired loans and leases	386	380
Allowance for all other loans and leases	3,000	3,541
Total allowance	3,386	3,921		4,997
Real estate segment [Member] | Commercial and industrial-owner occupied [Member]
Financing Receivable, Impaired [Line Items]
Recorded balance of impaired loans	28,152	24,801
Allowance for impaired loans and leases	3,051	3,601
Allowance for all other loans and leases	17,591	18,328
Total allowance	20,642	21,929		20,403
Real estate segment [Member] | Construction, acquisition and development [Member]
Financing Receivable, Impaired [Line Items]
Recorded balance of impaired loans	111,263	128,179
Allowance for impaired loans and leases	11,736	21,581
Allowance for all other loans and leases	23,725	23,981
Total allowance	35,461	45,562		59,048
Real estate segment [Member] | Commercial [Member]
Financing Receivable, Impaired [Line Items]
Recorded balance of impaired loans	31,482	36,122
Allowance for impaired loans and leases	4,410	5,324
Allowance for all other loans and leases	34,972	34,120
Total allowance	39,382	39,444		33,439
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	3,141	4,021
Total allowance	3,141	4,021	3,446	4,126
All other receivables [Member]
Financing Receivable, Impaired [Line Items]
Recorded balance of impaired loans	1,011	2,424
Allowance for impaired loans and leases	260	317
Allowance for all other loans and leases	13,747	14,041
Total allowance	$ 14,007	$ 14,358	$ 11,120	$ 9,576