ALLOWANCE FOR CREDIT LOSSES (Details) (USD $) In Thousands	9 Months Ended		12 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Dec. 31, 2010
Changes in the allowance for credit losses [Roll Forward]
Balance, beginning of period	$ 196,913	$ 176,043	$ 176,043
Charge-offs	(115,615)	(136,266)	(191,022)
Recoveries	7,557	4,581	7,876
Provision	110,831	160,723	204,016
Balance, end of period	199,686	205,081	196,913
Commercial and industrial segment [Member]
Changes in the allowance for credit losses [Roll Forward]
Balance, beginning of period	22,479	21,154	21,154
Charge-offs	(15,660)	(10,097)	(11,879)
Recoveries	1,121	623	1,330
Provision	12,084	10,514	11,874
Balance, end of period	20,024	22,194	22,479
Consumer mortgages [Member] | Real estate segment [Member]
Changes in the allowance for credit losses [Roll Forward]
Balance, beginning of period	35,540	37,048	37,048
Charge-offs	(7,233)	(10,989)	(16,280)
Recoveries	848	1,025	1,448
Provision	10,346	7,421	13,324
Balance, end of period	39,501	34,505	35,540
Home equity [Member] | Real estate segment [Member]
Changes in the allowance for credit losses [Roll Forward]
Balance, beginning of period	7,305	7,218	7,218
Charge-offs	(4,185)	(4,077)	(5,215)
Recoveries	142	118	179
Provision	6,626	3,876	5,123
Balance, end of period	9,888	7,135	7,305
Agricultural [Member] | Real estate segment [Member]
Changes in the allowance for credit losses [Roll Forward]
Balance, beginning of period	4,997	4,192	4,192
Charge-offs	(3,310)	(713)	(1,201)
Recoveries	47	8	12
Provision	2,658	1,201	1,994
Balance, end of period	4,392	4,688	4,997
Commercial and industrial-owner occupied [Member] | Real estate segment [Member]
Changes in the allowance for credit losses [Roll Forward]
Balance, beginning of period	20,403	22,989	22,989
Charge-offs	(9,166)	(7,541)	(9,200)
Recoveries	293	205	399
Provision	9,940	7,076	6,215
Balance, end of period	21,470	22,729	20,403
Construction, acquisition and development [Member] | Real estate segment [Member]
Changes in the allowance for credit losses [Roll Forward]
Balance, beginning of period	59,048	46,193	46,193
Charge-offs	(56,823)	(87,607)	(122,596)
Recoveries	2,980	930	1,706
Provision	43,033	103,817	133,745
Balance, end of period	48,238	63,333	59,048
Commercial [Member] | Real estate segment [Member]
Changes in the allowance for credit losses [Roll Forward]
Balance, beginning of period	33,439	26,694	26,694
Charge-offs	(10,578)	(7,758)	(14,084)
Recoveries	705	137	845
Provision	15,997	14,252	19,984
Balance, end of period	39,563	33,325	33,439
Credit cards segment [Member]
Changes in the allowance for credit losses [Roll Forward]
Balance, beginning of period	4,126	3,481	3,481
Charge-offs	(2,366)	(3,569)	(4,559)
Recoveries	635	686	829
Provision	1,525	2,709	4,375
Balance, end of period	3,920	3,307	4,126
All other receivables [Member]
Changes in the allowance for credit losses [Roll Forward]
Balance, beginning of period	9,576	7,074	7,074
Charge-offs	(6,294)	(3,915)	(6,008)
Recoveries	786	849	1,128
Provision	8,622	9,857	7,382
Balance, end of period	$ 12,690	$ 13,865	$ 9,576