ALLOWANCE FOR LOAN LOSSES (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	$ 63,850	$ 61,324	$ 61,963	$ 55,686
Charge-offs	(4,842)	(6,120)	(11,572)	(11,508)
Recoveries	2,013	779	4,077	2,711
Provision	5,201	5,238	11,754	14,332
Ending Balance	66,222	61,221	66,222	61,221
Agricultural and Agricultural Real Estate
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	6,049	5,709	4,953	4,258
Charge-offs	(1,670)	(1,145)	(2,098)	(1,357)
Recoveries	198	0	533	14
Provision	774	2	1,963	1,651
Ending Balance	5,351	4,566	5,351	4,566
Residential Real Estate
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	1,572	1,857	1,785	2,224
Charge-offs	(3)	0	(316)	(211)
Recoveries	25	1	72	77
Provision	(152)	(8)	(99)	(240)
Ending Balance	1,442	1,850	1,442	1,850
Consumer
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	4,847	9,322	5,182	9,156
Charge-offs	(859)	(1,831)	(2,357)	(4,462)
Recoveries	313	378	1,449	1,045
Provision	462	1,177	489	3,307
Ending Balance	4,763	9,046	4,763	9,046
Commercial | Commercial
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	24,082	20,709	24,505	18,098
Charge-offs	(2,175)	(2,945)	(6,506)	(4,717)
Recoveries	1,273	158	1,642	562
Provision	2,105	4,147	5,644	8,126
Ending Balance	25,285	22,069	25,285	22,069
Commercial Real Estate | Commercial
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning Balance	27,300	23,727	25,538	21,950
Charge-offs	(135)	(199)	(295)	(761)
Recoveries	204	242	381	1,013
Provision	2,012	(80)	3,757	1,488
Ending Balance	$ 29,381	$ 23,690	$ 29,381	$ 23,690