ALLOWANCE FOR LOAN LOSSES AND CREDIT QUALITY (Aging Of The Recorded Investment In Past Due Loans) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Financing Receivable, Recorded Investment, Aging [Abstract]
Loans Not Past Due	$ 3,832,464	$ 3,799,432
30 to 89 Days Past Due	2,175	9,619
Nonaccrual	11,003	9,402
Total Past Due and Nonaccural	13,204	19,027
Total	3,845,668	3,818,459
Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total Past Due	26	6
Other commercial loans
Financing Receivable, Recorded Investment, Aging [Abstract]
Loans Not Past Due	116,507	123,922
30 to 89 Days Past Due	0	0
Nonaccrual	0	0
Total Past Due and Nonaccural	0	0
Total	116,507	123,922
Other commercial loans | Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total Past Due	0	0
Other consumer loans
Financing Receivable, Recorded Investment, Aging [Abstract]
Loans Not Past Due	73,015	74,102
30 to 89 Days Past Due	85	92
Nonaccrual	0	0
Total Past Due and Nonaccural	85	92
Total	73,100	74,194
Other consumer loans | Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total Past Due	0	0
Commercial and industrial loans:
Financing Receivable, Recorded Investment, Aging [Abstract]
Total	1,484,933	1,418,627
Commercial and industrial loans: | Working Capital Lines Of Credit Loans [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Loans Not Past Due	775,855	742,205
30 to 89 Days Past Due	0	11
Nonaccrual	2,998	1,459
Total Past Due and Nonaccural	2,998	1,470
Total	778,853	743,675
Commercial and industrial loans: | Working Capital Lines Of Credit Loans [Member] | Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total Past Due	0	0
Commercial and industrial loans: | Non-working capital loans
Financing Receivable, Recorded Investment, Aging [Abstract]
Loans Not Past Due	702,304	671,490
30 to 89 Days Past Due	0	0
Nonaccrual	3,776	3,462
Total Past Due and Nonaccural	3,776	3,462
Total	706,080	674,952
Commercial and industrial loans: | Non-working capital loans | Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total Past Due	0	0
Commercial Real Estate and Multi-Family Residential Loans [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total	1,480,008	1,443,021
Commercial Real Estate and Multi-Family Residential Loans [Member] | Construction and land development loans
Financing Receivable, Recorded Investment, Aging [Abstract]
Loans Not Past Due	236,060	215,713
30 to 89 Days Past Due	881	8,000
Nonaccrual	0	0
Total Past Due and Nonaccural	881	8,000
Total	236,941	223,713
Commercial Real Estate and Multi-Family Residential Loans [Member] | Construction and land development loans | Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total Past Due	0	0
Commercial Real Estate and Multi-Family Residential Loans [Member] | Owner Occupied Loans [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Loans Not Past Due	539,547	534,648
30 to 89 Days Past Due	0	0
Nonaccrual	3,314	3,620
Total Past Due and Nonaccural	3,314	3,620
Total	542,861	538,268
Commercial Real Estate and Multi-Family Residential Loans [Member] | Owner Occupied Loans [Member] | Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total Past Due	0	0
Commercial Real Estate and Multi-Family Residential Loans [Member] | Nonowner Occupied Loans [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Loans Not Past Due	506,476	507,696
30 to 89 Days Past Due	155	0
Nonaccrual	0	0
Total Past Due and Nonaccural	155	0
Total	506,631	507,696
Commercial Real Estate and Multi-Family Residential Loans [Member] | Nonowner Occupied Loans [Member] | Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total Past Due	0	0
Commercial Real Estate and Multi-Family Residential Loans [Member] | Multifamily Loans [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Loans Not Past Due	193,575	173,100
30 to 89 Days Past Due	0	244
Nonaccrual	0	0
Total Past Due and Nonaccural	0	244
Total	193,575	173,344
Commercial Real Estate and Multi-Family Residential Loans [Member] | Multifamily Loans [Member] | Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total Past Due	0	0
Agri-business and agricultural loans:
Financing Receivable, Recorded Investment, Aging [Abstract]
Total	317,055	382,926
Agri-business and agricultural loans: | Loans Secured By Farmland [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Loans Not Past Due	145,083	186,160
30 to 89 Days Past Due	0	0
Nonaccrual	283	283
Total Past Due and Nonaccural	283	283
Total	145,366	186,443
Agri-business and agricultural loans: | Loans Secured By Farmland [Member] | Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total Past Due	0	0
Agri-business and agricultural loans: | Loans For Agricultural Production [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Loans Not Past Due	171,689	196,483
30 to 89 Days Past Due	0	0
Nonaccrual	0	0
Total Past Due and Nonaccural	0	0
Total	171,689	196,483
Agri-business and agricultural loans: | Loans For Agricultural Production [Member] | Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total Past Due	0	0
Consumer 1-4 Family Mortgage Loans [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total	374,065	375,769
Consumer 1-4 Family Mortgage Loans [Member] | Closed End First Mortgage Loans [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Loans Not Past Due	179,003	177,410
30 to 89 Days Past Due	767	1,183
Nonaccrual	382	342
Total Past Due and Nonaccural	1,175	1,531
Total	180,178	178,941
Consumer 1-4 Family Mortgage Loans [Member] | Closed End First Mortgage Loans [Member] | Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total Past Due	26	6
Consumer 1-4 Family Mortgage Loans [Member] | Open End and Junior Lien Loans [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Loans Not Past Due	180,042	183,056
30 to 89 Days Past Due	287	89
Nonaccrual	250	236
Total Past Due and Nonaccural	537	325
Total	180,579	183,381
Consumer 1-4 Family Mortgage Loans [Member] | Open End and Junior Lien Loans [Member] | Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total Past Due	0	0
Consumer 1-4 Family Mortgage Loans [Member] | Residential Construction Loans [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Loans Not Past Due	13,308	13,447
30 to 89 Days Past Due	0	0
Nonaccrual	0	0
Total Past Due and Nonaccural	0	0
Total	13,308	13,447
Consumer 1-4 Family Mortgage Loans [Member] | Residential Construction Loans [Member] | Greater than 90 Days Past Due [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total Past Due	$ 0	$ 0