LOANS AND LEASES, Aging (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Aging of loan and lease portfolio [Abstract]
30-59 Days Past Due	$ 37,336	$ 71,328
60-89 Days Past Due	20,207	26,908
90 Plus Days Past Due	78,309	150,643
Total Past Due	135,852	248,879
Current	8,734,459	9,084,228
Total Outstanding	8,870,311	9,333,107
90 Plus Days Past Due still Accruing	3,434	8,500
Commercial and industrial segment [Member]
Aging of loan and lease portfolio [Abstract]
30-59 Days Past Due	5,571	13,037
60-89 Days Past Due	4,209	848
90 Plus Days Past Due	4,193	12,000
Total Past Due	13,973	25,885
Current	1,459,755	1,465,298
Total Outstanding	1,473,728	1,491,183
90 Plus Days Past Due still Accruing	12	675
Real estate segment [Member] | Consumer mortgages [Member]
Aging of loan and lease portfolio [Abstract]
30-59 Days Past Due	15,740	16,937
60-89 Days Past Due	6,485	4,481
90 Plus Days Past Due	14,569	20,640
Total Past Due	36,794	42,058
Current	1,908,396	1,909,505
Total Outstanding	1,945,190	1,951,563
90 Plus Days Past Due still Accruing	2,974	6,521
Real estate segment [Member] | Home equity [Member]
Aging of loan and lease portfolio [Abstract]
30-59 Days Past Due	1,837	1,258
60-89 Days Past Due	265	800
90 Plus Days Past Due	594	755
Total Past Due	2,696	2,813
Current	511,666	540,459
Total Outstanding	514,362	543,272
90 Plus Days Past Due still Accruing	0	173
Real estate segment [Member] | Agricultural [Member]
Aging of loan and lease portfolio [Abstract]
30-59 Days Past Due	666	1,140
60-89 Days Past Due	54	3,450
90 Plus Days Past Due	719	3,527
Total Past Due	1,439	8,117
Current	238,048	244,175
Total Outstanding	239,487	252,292
90 Plus Days Past Due still Accruing	0	123
Real estate segment [Member] | Commercial and industrial-owner occupied [Member]
Aging of loan and lease portfolio [Abstract]
30-59 Days Past Due	2,199	9,260
60-89 Days Past Due	844	1,290
90 Plus Days Past Due	12,977	7,323
Total Past Due	16,020	17,873
Current	1,285,555	1,313,600
Total Outstanding	1,301,575	1,331,473
90 Plus Days Past Due still Accruing	0	20
Real estate segment [Member] | Construction, acquisition and development [Member]
Aging of loan and lease portfolio [Abstract]
30-59 Days Past Due	4,826	22,436
60-89 Days Past Due	4,955	9,837
90 Plus Days Past Due	33,584	94,264
Total Past Due	43,365	126,537
Current	864,997	1,048,206
Total Outstanding	908,362	1,174,743
90 Plus Days Past Due still Accruing	0	197
Real estate segment [Member] | Commercial [Member]
Aging of loan and lease portfolio [Abstract]
30-59 Days Past Due	3,778	4,409
60-89 Days Past Due	2,702	4,712
90 Plus Days Past Due	9,397	10,507
Total Past Due	15,877	19,628
Current	1,738,145	1,797,323
Total Outstanding	1,754,022	1,816,951
90 Plus Days Past Due still Accruing	0	0
Credit cards segment [Member]
Aging of loan and lease portfolio [Abstract]
30-59 Days Past Due	595	793
60-89 Days Past Due	303	373
90 Plus Days Past Due	697	780
Total Past Due	1,595	1,946
Current	104,686	104,399
Total Outstanding	106,281	106,345
90 Plus Days Past Due still Accruing	299	330
All other receivables [Member]
Aging of loan and lease portfolio [Abstract]
30-59 Days Past Due	2,124	2,058
60-89 Days Past Due	390	1,117
90 Plus Days Past Due	1,579	847
Total Past Due	4,093	4,022
Current	623,211	661,263
Total Outstanding	627,304	665,285
90 Plus Days Past Due still Accruing	$ 149	$ 461