LOANS (Total Loans Outstanding) (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2016	Dec. 31, 2015	Mar. 31, 2015	Dec. 31, 2014
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total commercial loans	$ 2,729,089	$ 2,700,734
Total consumer loans	384,250	380,216
Subtotal	$ 3,113,339	$ 3,080,950
Percentage of Subtotal	100.00%	100.00%
Less: Allowance for loan losses	$ (43,284)	$ (43,610)	$ (45,677)	$ (46,262)
Net deferred loan fees	(39)	(21)
Loans, net	$ 3,070,016	$ 3,037,319
Commercial Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage of Total commercial loans	87.70%	87.70%
Other consumer loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total consumer loans	$ 53,327	$ 49,113
Percentage of Total consumer loans	1.70%	1.60%
Consumer Loan [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage of Total consumer loans	12.30%	12.30%
Commercial and Industrial Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total commercial loans	$ 1,205,755	$ 1,179,512
Percentage of Total commercial loans	38.70%	38.30%
Less: Allowance for loan losses	$ (20,465)	$ (21,564)	(23,024)	(22,785)
Commercial and Industrial Loans [Member] | Working Capital Lines Of Credit Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total commercial loans	$ 591,136	$ 581,025
Percentage of Total commercial loans	19.00%	18.90%
Commercial and Industrial Loans [Member] | Non-working Capital Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total commercial loans	$ 614,619	$ 598,487
Percentage of Total commercial loans	19.70%	19.40%
Commercial Real Estate and Multi-family Residential Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total commercial loans	$ 1,166,574	$ 1,130,053
Percentage of Total commercial loans	37.50%	36.70%
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	$ 206,378	$ 230,719
Percentage of Total commercial loans	6.60%	7.50%
Commercial Real Estate and Multi-family Residential Loans [Member] | Owner Occupied Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total commercial loans	$ 447,620	$ 412,026
Percentage of Total commercial loans	14.40%	13.40%
Commercial Real Estate and Multi-family Residential Loans [Member] | Nonowner Occupied Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total commercial loans	$ 408,273	$ 407,883
Percentage of Total commercial loans	13.10%	13.20%
Commercial Real Estate and Multi-family Residential Loans [Member] | Multifamily Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total commercial loans	$ 104,303	$ 79,425
Percentage of Total commercial loans	3.40%	2.60%
Agri-business and Agricultural Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total commercial loans	$ 273,143	$ 306,094
Percentage of Total commercial loans	8.80%	9.90%
Less: Allowance for loan losses	$ (2,454)	$ (2,445)	$ (1,627)	$ (1,790)
Agri-business and Agricultural Loans [Member] | Loans Secured By Farmland [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total commercial loans	$ 144,687	$ 164,375
Percentage of Total commercial loans	4.60%	5.30%
Agri-business and Agricultural Loans [Member] | Loans For Agricultural Production [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total commercial loans	$ 128,456	$ 141,719
Percentage of Total commercial loans	4.10%	4.60%
Other Commercial Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total commercial loans	$ 83,617	$ 85,075
Percentage of Total commercial loans	2.70%	2.80%
Total Consumer 1 To 4 Family Mortgage Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total consumer loans	$ 330,923	$ 331,103
Percentage of Total consumer loans	10.60%	10.70%
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	$ 161,701	$ 158,062
Percentage of Total consumer loans	5.20%	5.10%
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	$ 160,734	$ 163,700
Percentage of Total consumer loans	5.20%	5.30%
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	$ 8,488	$ 9,341
Percentage of Total consumer loans	0.30%	0.30%