LOANS (Total Loans Outstanding) (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2015	Dec. 31, 2014	Jun. 30, 2015	Sep. 30, 2014	Jun. 30, 2014	Dec. 31, 2013
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total commercial loans	$ 2,600,176	$ 2,410,934
Total consumer loans	372,118	351,670
Subtotal	$ 2,972,294	$ 2,762,604
Percentage of Subtotal	100.00%	100.00%
Less: Allowance for loan losses	$ (44,694)	$ (46,262)	$ (44,816)	$ (46,387)	$ (45,605)	$ (48,797)
Net deferred loan fees	(14)	(284)
Loans, net	$ 2,927,586	$ 2,716,058
Commercial Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage of Total commercial loans	87.50%	87.30%
Other consumer loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage of Total consumer loans	1.70%	1.80%
Consumer Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage of Total consumer loans	12.50%	12.70%
Commercial and Industrial Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total commercial loans	$ 1,171,316	$ 1,035,373
Percentage of Total commercial loans	39.40%	37.50%
Less: Allowance for loan losses	$ (22,313)	$ (22,785)	(22,360)	(21,985)	(20,922)	(21,005)
Commercial and Industrial Loans [Member] | Working Capital Lines Of Credit Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total commercial loans	$ 593,780	$ 544,043
Percentage of Total commercial loans	20.00%	19.70%
Commercial and Industrial Loans [Member] | Non-working Capital Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total commercial loans	$ 577,536	$ 491,330
Percentage of Total commercial loans	19.40%	17.80%
Commercial Real Estate and Multi-family Residential Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total commercial loans	$ 1,096,814	$ 1,026,059
Percentage of Total commercial loans	36.90%	37.10%
Commercial Real Estate and Multi-family Residential Loans [Member] | Construction and Land Development Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total commercial loans	$ 176,945	$ 156,636
Percentage of Total commercial loans	6.00%	5.70%
Commercial Real Estate and Multi-family Residential Loans [Member] | Owner Occupied Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total commercial loans	$ 409,004	$ 403,154
Percentage of Total commercial loans	13.80%	14.60%
Commercial Real Estate and Multi-family Residential Loans [Member] | Nonowner Occupied Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total commercial loans	$ 417,790	$ 394,458
Percentage of Total commercial loans	14.10%	14.30%
Commercial Real Estate and Multi-family Residential Loans [Member] | Multifamily Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total commercial loans	$ 93,075	$ 71,811
Percentage of Total commercial loans	3.10%	2.60%
Agri-business and Agricultural Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total commercial loans	$ 249,070	$ 273,787
Percentage of Total commercial loans	8.40%	9.90%
Less: Allowance for loan losses	$ (1,989)	$ (1,790)	$ (1,881)	$ (1,375)	$ (1,404)	$ (1,682)
Agri-business and Agricultural Loans [Member] | Loans Secured By Farmland [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total commercial loans	$ 155,106	$ 137,407
Percentage of Total commercial loans	5.20%	5.00%
Agri-business and Agricultural Loans [Member] | Loans For Agricultural Production [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total commercial loans	$ 93,964	$ 136,380
Percentage of Total commercial loans	3.20%	4.90%
Other Commercial Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total commercial loans	$ 82,976	$ 75,715
Percentage of Total commercial loans	2.80%	2.70%
Total Consumer 1 To 4 Family Mortgage Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total consumer loans	$ 322,949	$ 302,129
Percentage of Total consumer loans	10.90%	10.90%
Total Consumer 1 To 4 Family Mortgage Loans [Member] | Closed End First Mortgage Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total consumer loans	$ 154,019	$ 145,167
Percentage of Total consumer loans	5.20%	5.30%
Total Consumer 1 To 4 Family Mortgage Loans [Member] | Open End And Junior Lien Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total consumer loans	$ 160,485	$ 150,220
Percentage of Total consumer loans	5.40%	5.40%
Total Consumer 1 To 4 Family Mortgage Loans [Member] | Residential Construction and Land Development Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total consumer loans	$ 8,445	$ 6,742
Percentage of Total consumer loans	0.30%	0.20%
Other Consumer [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total consumer loans	$ 49,169	$ 49,541