LOANS (Details) (USD $)	9 Months Ended	12 Months Ended
	Sep. 30, 2012	Dec. 31, 2011	Jun. 30, 2012	Sep. 30, 2011	Jun. 30, 2011	Dec. 31, 2010
Accounts, Notes, Loans and Financing Receivable [Line Items]
Subtotal	$ 2,203,798	$ 2,234,037
Less: Allowance for loan losses	(51,912,000)	(53,400,000)	(51,817,000)	(52,073,000)	(51,260,000)	(45,007,000)
Net deferred loan fees	(410)	(328)
Loans, net	2,151,476,000	2,180,309,000
Ratio of loan to all loans (in hundredths)	100.00%	100.00%
Commercial and Industrial Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total commercial loans	828,831	751,156
Less: Allowance for loan losses	(21,354,000)	(22,830,000)	(19,696,000)	(23,752,000)	(22,999,000)	(21,479,000)
Ratio of loan to all loans (in hundredths)	37.60%	33.60%
Commercial Real Estate and Multi-family Residential Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total commercial loans	785,250	852,520
Ratio of loan to all loans (in hundredths)	35.60%	38.20%
Agri-business and Agricultural Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total commercial loans	214,087	237,929
Less: Allowance for loan losses	(1,344,000)	(695,000)	(1,419,000)	(651,000)	(948,000)	(1,318,000)
Ratio of loan to all loans (in hundredths)	9.70%	10.70%
Residential Construction and Land Development Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total consumer loans	11,303	5,462
Ratio of loan to all loans (in hundredths)	0.50%	0.20%
Non-working Capital Loans [Member] | Commercial and Industrial Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Ratio of loan to all loans (in hundredths)		16.90%
Construction and Land Development Loans [Member] | Commercial Real Estate and Multi-family Residential Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total commercial loans	87,949	82,284
Ratio of loan to all loans (in hundredths)	4.00%	3.70%
Owner Occupied Loans [Member] | Commercial Real Estate and Multi-family Residential Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total commercial loans	363,673	346,669
Ratio of loan to all loans (in hundredths)	16.50%	15.50%
Nonowner Occupied Loans [Member] | Commercial Real Estate and Multi-family Residential Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total commercial loans	308,146	385,090
Ratio of loan to all loans (in hundredths)	14.00%	17.20%
Multifamily Loans [Member] | Commercial Real Estate and Multi-family Residential Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total commercial loans	25,482	38,477
Ratio of loan to all loans (in hundredths)	1.20%	1.70%
Loans Secured By Farmland [Member] | Agri-business and Agricultural Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Ratio of loan to all loans (in hundredths)	5.40%
Other Commerical Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total commercial loans	44,982	58,278
Ratio of loan to all loans (in hundredths)	2.00%	2.60%
Commercial Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total commercial loans	1,873,150	1,899,883
Ratio of loan to all loans (in hundredths)	85.00%	85.00%
Closed End First Mortgage Loans [Member] | Residential Construction and Land Development Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total consumer loans	106,147	106,999
Ratio of loan to all loans (in hundredths)	4.80%	4.80%
Open End and Junior Lien Loans [Member] | Residential Construction and Land Development Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total consumer loans	168,507	175,694
Ratio of loan to all loans (in hundredths)	7.60%	7.90%
Other Consumer Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total consumer loans	44,691	45,999
Ratio of loan to all loans (in hundredths)	2.00%	2.10%
Consumer Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total consumer loans	$ 330,648	$ 334,154
Ratio of loan to all loans (in hundredths)	15.00%	15.00%