LOANS (Loans by credit quality indicator) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023	Dec. 31, 2023
Amortized Cost Basis of Term Loans by Year of Origination
Year One	$ 667,431		$ 667,431		$ 2,247,517
Year Two	2,041,673		2,041,673		3,073,040
Year Three	2,829,815		2,829,815		2,172,951
Year Four	1,926,233		1,926,233		802,905
Year Five	697,712		697,712		720,479
Year Six and Prior	1,640,947		1,640,947		1,148,381
Revolving	1,804,498		1,804,498		1,903,372
Total	11,608,309		11,608,309		12,068,645
Charge-offs
Year One			10		531
Year Two			59		1,953
Year Three			1,358		958
Year Four			846		1,527
Year Five			3,552		981
Year Six and Prior			308		2,272
Revolving			5,348		11,392
Total charge-offs	7,388	$ 9,613	11,481	$ 11,764	19,614
Pass
Amortized Cost Basis of Term Loans by Year of Origination
Year One	641,750		641,750		2,085,645
Year Two	1,896,034		1,896,034		2,901,425
Year Three	2,566,916		2,566,916		2,128,112
Year Four	1,824,676		1,824,676		773,698
Year Five	661,487		661,487		651,885
Year Six and Prior	1,409,680		1,409,680		1,012,958
Revolving	1,661,918		1,661,918		1,838,626
Total	10,662,461		10,662,461		11,392,349
Watch
Amortized Cost Basis of Term Loans by Year of Origination
Year One	21,393		21,393		103,921
Year Two	105,773		105,773		130,920
Year Three	136,393		136,393		33,047
Year Four	80,661		80,661		11,501
Year Five	9,919		9,919		38,127
Year Six and Prior	144,675		144,675		73,492
Revolving	90,499		90,499		31,236
Total	589,313		589,313		422,244
Substandard
Amortized Cost Basis of Term Loans by Year of Origination
Year One	4,288		4,288		57,951
Year Two	39,866		39,866		40,695
Year Three	126,506		126,506		11,792
Year Four	20,896		20,896		17,706
Year Five	26,306		26,306		30,467
Year Six and Prior	86,592		86,592		61,931
Revolving	52,081		52,081		33,510
Total	356,535		356,535		254,052
Commercial and industrial | Commercial and industrial
Amortized Cost Basis of Term Loans by Year of Origination
Year One	309,168		309,168		648,895
Year Two	546,425		546,425		811,664
Year Three	667,020		667,020		336,793
Year Four	282,382		282,382		196,484
Year Five	159,444		159,444		99,388
Year Six and Prior	376,493		376,493		338,217
Revolving	1,200,307		1,200,307		1,220,606
Total	3,541,239		3,541,239		3,652,047
Charge-offs
Year One			0		245
Year Two			8		794
Year Three			1,127		680
Year Four			784		1,425
Year Five			3,283		563
Year Six and Prior			30		1,949
Revolving			2,979		2,966
Total charge-offs	5,914	3,686	8,211	5,137	8,622
Commercial and industrial | Commercial and industrial | Pass
Amortized Cost Basis of Term Loans by Year of Origination
Year One	295,000		295,000		608,030
Year Two	512,146		512,146		779,218
Year Three	618,107		618,107		333,900
Year Four	261,964		261,964		187,406
Year Five	154,860		154,860		78,455
Year Six and Prior	358,689		358,689		327,775
Revolving	1,068,196		1,068,196		1,159,397
Total	3,268,962		3,268,962		3,474,181
Commercial and industrial | Commercial and industrial | Watch
Amortized Cost Basis of Term Loans by Year of Origination
Year One	13,856		13,856		20,694
Year Two	28,148		28,148		19,788
Year Three	32,584		32,584		257
Year Four	18,695		18,695		3,631
Year Five	833		833		2,398
Year Six and Prior	8,763		8,763		2,953
Revolving	81,055		81,055		28,749
Total	183,934		183,934		78,470
Commercial and industrial | Commercial and industrial | Substandard
Amortized Cost Basis of Term Loans by Year of Origination
Year One	312		312		20,171
Year Two	6,131		6,131		12,658
Year Three	16,329		16,329		2,636
Year Four	1,723		1,723		5,447
Year Five	3,751		3,751		18,535
Year Six and Prior	9,041		9,041		7,489
Revolving	51,056		51,056		32,460
Total	88,343		88,343		99,396
Commercial and industrial | Paycheck Protection Program ("PPP")
Amortized Cost Basis of Term Loans by Year of Origination
Year One	0		0		0
Year Two	0		0		0
Year Three	0		0		2,727
Year Four	1,833		1,833		50
Year Five	31		31		0
Year Six and Prior	0		0		0
Revolving	0		0		0
Total	1,864		1,864		2,777
Charge-offs
Year One			0		0
Year Two			0		0
Year Three			0		0
Year Four			0		0
Year Five			0		0
Year Six and Prior			0		0
Revolving			0		0
Total charge-offs			0		0
Commercial and industrial | Paycheck Protection Program ("PPP") | Pass
Amortized Cost Basis of Term Loans by Year of Origination
Year One	0		0		0
Year Two	0		0		0
Year Three	0		0		2,591
Year Four	1,610		1,610		50
Year Five	31		31		0
Year Six and Prior	0		0		0
Revolving	0		0		0
Total	1,641		1,641		2,641
Commercial and industrial | Paycheck Protection Program ("PPP") | Watch
Amortized Cost Basis of Term Loans by Year of Origination
Year One	0		0		0
Year Two	0		0		0
Year Three	0		0		89
Year Four	223		223		0
Year Five	0		0		0
Year Six and Prior	0		0		0
Revolving	0		0		0
Total	223		223		89
Commercial and industrial | Paycheck Protection Program ("PPP") | Substandard
Amortized Cost Basis of Term Loans by Year of Origination
Year One	0		0		0
Year Two	0		0		0
Year Three	0		0		47
Year Four	0		0		0
Year Five	0		0		0
Year Six and Prior	0		0		0
Revolving	0		0		0
Total	0		0		47
Commercial and industrial | Owner occupied commercial real estate
Amortized Cost Basis of Term Loans by Year of Origination
Year One	113,538		113,538		483,639
Year Two	453,622		453,622		584,334
Year Three	579,995		579,995		815,360
Year Four	727,324		727,324		239,528
Year Five	224,087		224,087		239,910
Year Six and Prior	414,400		414,400		234,332
Revolving	42,998		42,998		41,072
Total	2,555,964		2,555,964		2,638,175
Charge-offs
Year One			0		0
Year Two			0		802
Year Three			87		0
Year Four			0		5
Year Five			248		0
Year Six and Prior			62		63
Revolving			0		0
Total charge-offs	397	5	397	19	870
Commercial and industrial | Owner occupied commercial real estate | Pass
Amortized Cost Basis of Term Loans by Year of Origination
Year One	110,750		110,750		443,683
Year Two	425,238		425,238		547,898
Year Three	510,666		510,666		799,978
Year Four	711,407		711,407		225,257
Year Five	200,668		200,668		225,405
Year Six and Prior	368,105		368,105		224,608
Revolving	42,998		42,998		41,072
Total	2,369,832		2,369,832		2,507,901
Commercial and industrial | Owner occupied commercial real estate | Watch
Amortized Cost Basis of Term Loans by Year of Origination
Year One	2,788		2,788		8,052
Year Two	4,983		4,983		25,947
Year Three	36,793		36,793		13,114
Year Four	11,004		11,004		2,662
Year Five	2,920		2,920		8,115
Year Six and Prior	39,109		39,109		7,553
Revolving	0		0		0
Total	97,597		97,597		65,443
Commercial and industrial | Owner occupied commercial real estate | Substandard
Amortized Cost Basis of Term Loans by Year of Origination
Year One	0		0		31,904
Year Two	23,401		23,401		10,489
Year Three	32,536		32,536		2,268
Year Four	4,913		4,913		11,609
Year Five	20,499		20,499		6,390
Year Six and Prior	7,186		7,186		2,171
Revolving	0		0		0
Total	88,535		88,535		64,831
Commercial and industrial | Non-owner occupied commercial real estate
Amortized Cost Basis of Term Loans by Year of Origination
Year One	79,275		79,275		557,126
Year Two	491,074		491,074		692,427
Year Three	692,961		692,961		433,048
Year Four	414,903		414,903		207,164
Year Five	185,171		185,171		294,124
Year Six and Prior	554,062		554,062		342,844
Revolving	16,812		16,812		26,978
Total	2,434,258		2,434,258		2,553,711
Charge-offs
Year One			0		0
Year Two			0		52
Year Three			0		0
Year Four			0		29
Year Five			0		399
Year Six and Prior			0		147
Revolving			0		0
Total charge-offs	0	29	0	29	627
Commercial and industrial | Non-owner occupied commercial real estate | Pass
Amortized Cost Basis of Term Loans by Year of Origination
Year One	75,332		75,332		480,683
Year Two	423,879		423,879		656,824
Year Three	648,769		648,769		423,420
Year Four	401,764		401,764		203,330
Year Five	181,074		181,074		262,541
Year Six and Prior	434,109		434,109		251,499
Revolving	16,812		16,812		26,978
Total	2,181,739		2,181,739		2,305,275
Commercial and industrial | Non-owner occupied commercial real estate | Watch
Amortized Cost Basis of Term Loans by Year of Origination
Year One	3,943		3,943		71,400
Year Two	67,195		67,195		34,651
Year Three	44,057		44,057		8,237
Year Four	4,601		4,601		3,834
Year Five	4,097		4,097		27,345
Year Six and Prior	67,735		67,735		57,083
Revolving	0		0		0
Total	191,628		191,628		202,550
Commercial and industrial | Non-owner occupied commercial real estate | Substandard
Amortized Cost Basis of Term Loans by Year of Origination
Year One	0		0		5,043
Year Two	0		0		952
Year Three	135		135		1,391
Year Four	8,538		8,538		0
Year Five	0		0		4,238
Year Six and Prior	52,218		52,218		34,262
Revolving	0		0		0
Total	60,891		60,891		45,886
Commercial and industrial | Real estate construction
Amortized Cost Basis of Term Loans by Year of Origination
Year One	67,207		67,207		284,148
Year Two	333,642		333,642		510,388
Year Three	482,872		482,872		186,022
Year Four	148,974		148,974		10,068
Year Five	7,615		7,615		11,048
Year Six and Prior	35,006		35,006		3,470
Revolving	7,410		7,410		6,572
Total	1,082,726		1,082,726		1,011,716
Charge-offs
Year One			0		284
Year Two			0		0
Year Three			0		0
Year Four			0		32
Year Five			0		0
Year Six and Prior			0		0
Revolving			0		0
Total charge-offs	0	0	0	0	316
Commercial and industrial | Real estate construction | Pass
Amortized Cost Basis of Term Loans by Year of Origination
Year One	64,091		64,091		283,519
Year Two	323,350		323,350		468,646
Year Three	404,646		404,646		176,604
Year Four	104,823		104,823		9,889
Year Five	7,544		7,544		11,048
Year Six and Prior	10,269		10,269		3,405
Revolving	7,324		7,324		6,486
Total	922,047		922,047		959,597
Commercial and industrial | Real estate construction | Watch
Amortized Cost Basis of Term Loans by Year of Origination
Year One	0		0		629
Year Two	917		917		33,220
Year Three	20,576		20,576		9,418
Year Four	44,063		44,063		72
Year Five	71		71		0
Year Six and Prior	24,656		24,656		65
Revolving	0		0		0
Total	90,283		90,283		43,404
Commercial and industrial | Real estate construction | Substandard
Amortized Cost Basis of Term Loans by Year of Origination
Year One	3,116		3,116		0
Year Two	9,375		9,375		8,522
Year Three	57,650		57,650		0
Year Four	88		88		107
Year Five	0		0		0
Year Six and Prior	81		81		0
Revolving	86		86		86
Total	70,396		70,396		8,715
Agricultural and agricultural real estate
Amortized Cost Basis of Term Loans by Year of Origination
Year One	52,041		52,041		154,922
Year Two	116,849		116,849		232,248
Year Three	198,973		198,973		116,740
Year Four	101,346		101,346		67,632
Year Five	51,446		51,446		29,172
Year Six and Prior	70,717		70,717		56,603
Revolving	211,586		211,586		261,867
Total	802,958		802,958		919,184
Charge-offs
Year One			0		0
Year Two			0		0
Year Three			52		0
Year Four			0		9
Year Five			8		0
Year Six and Prior			167		1
Revolving			648		5,309
Total charge-offs	608	5,309	875	5,309	5,319
Agricultural and agricultural real estate | Pass
Amortized Cost Basis of Term Loans by Year of Origination
Year One	50,760		50,760		152,665
Year Two	113,573		113,573		208,375
Year Three	178,283		178,283		114,798
Year Four	98,886		98,886		67,006
Year Five	49,712		49,712		28,247
Year Six and Prior	58,360		58,360		43,663
Revolving	204,938		204,938		260,941
Total	754,512		754,512		875,695
Agricultural and agricultural real estate | Watch
Amortized Cost Basis of Term Loans by Year of Origination
Year One	755		755		2,245
Year Two	3,095		3,095		16,257
Year Three	1,291		1,291		293
Year Four	420		420		622
Year Five	152		152		70
Year Six and Prior	73		73		349
Revolving	6,648		6,648		427
Total	12,434		12,434		20,263
Agricultural and agricultural real estate | Substandard
Amortized Cost Basis of Term Loans by Year of Origination
Year One	526		526		12
Year Two	181		181		7,616
Year Three	19,399		19,399		1,649
Year Four	2,040		2,040		4
Year Five	1,582		1,582		855
Year Six and Prior	12,284		12,284		12,591
Revolving	0		0		499
Total	36,012		36,012		23,226
Residential real estate
Amortized Cost Basis of Term Loans by Year of Origination
Year One	26,826		26,826		72,382
Year Two	62,309		62,309		178,687
Year Three	156,632		156,632		245,707
Year Four	219,656		219,656		74,152
Year Five	66,660		66,660		42,974
Year Six and Prior	181,381		181,381		164,393
Revolving	19,937		19,937		19,534
Total	733,401		733,401		797,829
Charge-offs
Year One			0		0
Year Two			0		59
Year Three			0		124
Year Four			0		0
Year Five			0		0
Year Six and Prior			0		0
Revolving			0		0
Total charge-offs	0	59	0	59	183
Residential real estate | Pass
Amortized Cost Basis of Term Loans by Year of Origination
Year One	26,824		26,824		71,470
Year Two	61,048		61,048		177,564
Year Three	155,494		155,494		241,362
Year Four	214,982		214,982		73,029
Year Five	64,465		64,465		42,526
Year Six and Prior	173,439		173,439		155,899
Revolving	19,687		19,687		19,534
Total	715,939		715,939		781,384
Residential real estate | Watch
Amortized Cost Basis of Term Loans by Year of Origination
Year One	2		2		171
Year Two	534		534		973
Year Three	998		998		945
Year Four	1,452		1,452		659
Year Five	1,829		1,829		158
Year Six and Prior	3,537		3,537		4,845
Revolving	250		250		0
Total	8,602		8,602		7,751
Residential real estate | Substandard
Amortized Cost Basis of Term Loans by Year of Origination
Year One	0		0		741
Year Two	727		727		150
Year Three	140		140		3,400
Year Four	3,222		3,222		464
Year Five	366		366		290
Year Six and Prior	4,405		4,405		3,649
Revolving	0		0		0
Total	8,860		8,860		8,694
Consumer
Amortized Cost Basis of Term Loans by Year of Origination
Year One	19,376		19,376		46,405
Year Two	37,752		37,752		63,292
Year Three	51,362		51,362		36,554
Year Four	29,815		29,815		7,827
Year Five	3,258		3,258		3,863
Year Six and Prior	8,888		8,888		8,522
Revolving	305,448		305,448		326,743
Total	455,899		455,899		493,206
Charge-offs
Year One			10		2
Year Two			51		246
Year Three			92		154
Year Four			62		27
Year Five			13		19
Year Six and Prior			49		112
Revolving			1,721		3,117
Total charge-offs	469	$ 525	1,998	$ 1,211	3,677
Consumer | Pass
Amortized Cost Basis of Term Loans by Year of Origination
Year One	18,993		18,993		45,595
Year Two	36,800		36,800		62,900
Year Three	50,951		50,951		35,459
Year Four	29,240		29,240		7,731
Year Five	3,133		3,133		3,663
Year Six and Prior	6,709		6,709		6,109
Revolving	301,963		301,963		324,218
Total	447,789		447,789		485,675
Consumer | Watch
Amortized Cost Basis of Term Loans by Year of Origination
Year One	49		49		730
Year Two	901		901		84
Year Three	94		94		694
Year Four	203		203		21
Year Five	17		17		41
Year Six and Prior	802		802		644
Revolving	2,546		2,546		2,060
Total	4,612		4,612		4,274
Consumer | Substandard
Amortized Cost Basis of Term Loans by Year of Origination
Year One	334		334		80
Year Two	51		51		308
Year Three	317		317		401
Year Four	372		372		75
Year Five	108		108		159
Year Six and Prior	1,377		1,377		1,769
Revolving	939		939		465
Total	$ 3,498		$ 3,498		$ 3,257