LOANS AND LEASES, Non-performing and Nonaccrual Loans and Leases (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
LOANS AND LEASES [Abstract]
Days past due of principal or interest at which loans and leases may be placed in non-accrual status	90 days	90 days
Non-performing loans and leases [Abstract]
Non-accrual loans and leases	$ 207,241,000	$ 276,798,000
Loans and leases 90 days or more past due, still accruing	1,210,000	3,434,000
Restructured loans and leases still accruing	25,099,000	42,018,000
Total non-performing loans and leases	233,550,000	322,250,000
Nonaccrual loans and leases [Abstract]
Non-accrual loans and leases	207,241,000	276,798,000
Total interest earned on NPLs	4,300,000	12,600,000	11,200,000
Gross interest income which would have been recorded for NPLs	15,600,000	18,700,000	21,700,000
Commercial and industrial segment [Member]
Non-performing loans and leases [Abstract]
Non-accrual loans and leases	9,311,000	12,260,000
Loans and leases 90 days or more past due, still accruing	414,000	12,000
Nonaccrual loans and leases [Abstract]
Non-accrual loans and leases	9,311,000	12,260,000
Real estate segment [Member] | Consumer mortgages [Member]
Non-performing loans and leases [Abstract]
Non-accrual loans and leases	36,133,000	47,878,000
Loans and leases 90 days or more past due, still accruing	512,000	2,974,000
Nonaccrual loans and leases [Abstract]
Non-accrual loans and leases	36,133,000	47,878,000
Real estate segment [Member] | Home equity [Member]
Non-performing loans and leases [Abstract]
Non-accrual loans and leases	3,497,000	2,036,000
Loans and leases 90 days or more past due, still accruing	0	0
Nonaccrual loans and leases [Abstract]
Non-accrual loans and leases	3,497,000	2,036,000
Real estate segment [Member] | Agricultural [Member]
Non-performing loans and leases [Abstract]
Non-accrual loans and leases	7,587,000	4,179,000
Loans and leases 90 days or more past due, still accruing	10,000	0
Nonaccrual loans and leases [Abstract]
Non-accrual loans and leases	7,587,000	4,179,000
Real estate segment [Member] | Commercial and industrial-owner occupied [Member]
Non-performing loans and leases [Abstract]
Non-accrual loans and leases	20,910,000	33,112,000
Loans and leases 90 days or more past due, still accruing	19,000	0
Nonaccrual loans and leases [Abstract]
Non-accrual loans and leases	20,910,000	33,112,000
Real estate segment [Member] | Construction, acquisition and development [Member]
Non-performing loans and leases [Abstract]
Non-accrual loans and leases	66,635,000	133,110,000
Loans and leases 90 days or more past due, still accruing	0	0
Nonaccrual loans and leases [Abstract]
Non-accrual loans and leases	66,635,000	133,110,000
Real estate segment [Member] | Commercial [Member]
Non-performing loans and leases [Abstract]
Non-accrual loans and leases	57,656,000	40,616,000
Loans and leases 90 days or more past due, still accruing	0	0
Nonaccrual loans and leases [Abstract]
Non-accrual loans and leases	57,656,000	40,616,000
Credit cards segment [Member]
Non-performing loans and leases [Abstract]
Non-accrual loans and leases	415,000	594,000
Loans and leases 90 days or more past due, still accruing	228,000	299,000
Nonaccrual loans and leases [Abstract]
Non-accrual loans and leases	415,000	594,000
All other receivables [Member]
Non-performing loans and leases [Abstract]
Non-accrual loans and leases	5,097,000	3,013,000
Loans and leases 90 days or more past due, still accruing	27,000	149,000
Nonaccrual loans and leases [Abstract]
Non-accrual loans and leases	$ 5,097,000	$ 3,013,000