ALLOWANCE FOR CREDIT LOSSES AND CREDIT QUALITY INFORMATION - Schedule of Credit Quality Indicators (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022
Financing Receivable, Credit Quality Indicator [Line Items]
Total Loans	$ 12,675,621	$ 11,702,372	$ 12,675,621	$ 11,702,372	$ 11,909,436
Total charge offs	16,847	7,498	46,387	16,316
Commercial | Commercial and industrial
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	898,486		898,486		1,184,837
Year two, originated, fiscal year before current fiscal year	913,460		913,460		545,612
Year three, originated, two years before current fiscal year	330,094		330,094		401,753
Year four, originated, three years before current fiscal year	276,160		276,160		258,295
Year five, originated, four years before current fiscal year	145,062		145,062		191,193
Prior	416,420		416,420		284,366
Revolving loans amortized cost basis	8,710		8,710		8,099
Revolving loans converted to term	261,345		261,345		260,171
Total Loans	3,249,737	3,169,478	3,249,737	3,169,478	3,134,326
Year one, current fiscal year charge offs			399
Year two, current fiscal year charge offs			5,410
Year three, current fiscal year charge offs			8,437
Year four, current fiscal year charge offs			1,398
Year five, current fiscal year charge offs			6,435
Prior year charge offs			8,417
Revolving loans amortized cost basis charge offs			0
Revolving loans converted to term gross charge offs			0
Total charge offs	10,675	5,120	30,496	11,308
Commercial | Commercial and industrial | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	830,232		830,232		1,123,803
Year two, originated, fiscal year before current fiscal year	854,412		854,412		501,761
Year three, originated, two years before current fiscal year	321,269		321,269		387,225
Year four, originated, three years before current fiscal year	264,724		264,724		211,310
Year five, originated, four years before current fiscal year	119,282		119,282		153,713
Prior	396,845		396,845		276,588
Revolving loans amortized cost basis	8,710		8,710		8,099
Revolving loans converted to term	243,969		243,969		250,486
Total Loans	3,039,443		3,039,443		2,912,985
Commercial | Commercial and industrial | Special mention
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	14,913		14,913		28,672
Year two, originated, fiscal year before current fiscal year	24,194		24,194		27,689
Year three, originated, two years before current fiscal year	2,917		2,917		7,585
Year four, originated, three years before current fiscal year	350		350		9,451
Year five, originated, four years before current fiscal year	798		798		347
Prior	7		7		1,010
Revolving loans amortized cost basis	0		0		0
Revolving loans converted to term	861		861		2,596
Total Loans	44,040		44,040		77,350
Commercial | Commercial and industrial | Substandard or Lower
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	53,341		53,341		32,362
Year two, originated, fiscal year before current fiscal year	34,854		34,854		16,162
Year three, originated, two years before current fiscal year	5,908		5,908		6,943
Year four, originated, three years before current fiscal year	11,086		11,086		37,534
Year five, originated, four years before current fiscal year	24,982		24,982		37,133
Prior	19,568		19,568		6,768
Revolving loans amortized cost basis	0		0		0
Revolving loans converted to term	16,515		16,515		7,089
Total Loans	166,254		166,254		143,991
Commercial | Owner-occupied commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	301,583		301,583		301,255
Year two, originated, fiscal year before current fiscal year	290,518		290,518		326,888
Year three, originated, two years before current fiscal year	284,754		284,754		281,461
Year four, originated, three years before current fiscal year	225,770		225,770		231,118
Year five, originated, four years before current fiscal year	219,451		219,451		118,254
Prior	409,995		409,995		400,897
Revolving loans amortized cost basis	0		0		0
Revolving loans converted to term	192,100		192,100		149,709
Total Loans	1,924,171	1,788,591	1,924,171	1,788,591	1,809,582
Year one, current fiscal year charge offs			0
Year two, current fiscal year charge offs			0
Year three, current fiscal year charge offs			0
Year four, current fiscal year charge offs			0
Year five, current fiscal year charge offs			184
Prior year charge offs			0
Revolving loans amortized cost basis charge offs			0
Revolving loans converted to term gross charge offs			0
Total charge offs	0	0	184	179
Commercial | Owner-occupied commercial | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	289,740		289,740		280,898
Year two, originated, fiscal year before current fiscal year	269,796		269,796		325,388
Year three, originated, two years before current fiscal year	268,593		268,593		258,177
Year four, originated, three years before current fiscal year	213,060		213,060		226,717
Year five, originated, four years before current fiscal year	206,999		206,999		106,390
Prior	361,669		361,669		363,420
Revolving loans amortized cost basis	0		0		0
Revolving loans converted to term	171,762		171,762		132,942
Total Loans	1,781,619		1,781,619		1,693,932
Commercial | Owner-occupied commercial | Special mention
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	2,907		2,907		17,376
Year two, originated, fiscal year before current fiscal year	2,182		2,182		0
Year three, originated, two years before current fiscal year	6,638		6,638		0
Year four, originated, three years before current fiscal year	1,122		1,122		0
Year five, originated, four years before current fiscal year	9,621		9,621		0
Prior	5,601		5,601		2,166
Revolving loans amortized cost basis	0		0		0
Revolving loans converted to term	1,615		1,615		3,351
Total Loans	29,686		29,686		22,893
Commercial | Owner-occupied commercial | Substandard or Lower
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	8,936		8,936		2,981
Year two, originated, fiscal year before current fiscal year	18,540		18,540		1,500
Year three, originated, two years before current fiscal year	9,523		9,523		23,284
Year four, originated, three years before current fiscal year	11,588		11,588		4,401
Year five, originated, four years before current fiscal year	2,831		2,831		11,864
Prior	42,725		42,725		35,311
Revolving loans amortized cost basis	0		0		0
Revolving loans converted to term	18,723		18,723		13,416
Total Loans	112,866		112,866		92,757
Commercial | Commercial mortgages
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	701,545		701,545		520,094
Year two, originated, fiscal year before current fiscal year	480,687		480,687		601,511
Year three, originated, two years before current fiscal year	523,081		523,081		542,712
Year four, originated, three years before current fiscal year	491,212		491,212		558,818
Year five, originated, four years before current fiscal year	520,554		520,554		289,583
Prior	649,755		649,755		627,247
Revolving loans amortized cost basis	0		0		0
Revolving loans converted to term	278,889		278,889		211,119
Total Loans	3,645,723	3,280,379	3,645,723	3,280,379	3,351,084
Year one, current fiscal year charge offs			0
Year two, current fiscal year charge offs			83
Year three, current fiscal year charge offs			0
Year four, current fiscal year charge offs			217
Year five, current fiscal year charge offs			0
Prior year charge offs			0
Revolving loans amortized cost basis charge offs			0
Revolving loans converted to term gross charge offs			0
Total charge offs	300	544	300	581
Commercial | Commercial mortgages | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	682,033		682,033		516,783
Year two, originated, fiscal year before current fiscal year	478,103		478,103		600,226
Year three, originated, two years before current fiscal year	521,669		521,669		526,312
Year four, originated, three years before current fiscal year	475,369		475,369		549,788
Year five, originated, four years before current fiscal year	494,904		494,904		276,414
Prior	625,112		625,112		594,024
Revolving loans amortized cost basis	0		0		0
Revolving loans converted to term	263,124		263,124		210,550
Total Loans	3,540,314		3,540,314		3,274,097
Commercial | Commercial mortgages | Special mention
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	9,599		9,599		1,450
Year two, originated, fiscal year before current fiscal year	0		0		75
Year three, originated, two years before current fiscal year	69		69		3,848
Year four, originated, three years before current fiscal year	4,802		4,802		6,121
Year five, originated, four years before current fiscal year	24,401		24,401		9,596
Prior	19,797		19,797		32,014
Revolving loans amortized cost basis	0		0		0
Revolving loans converted to term	294		294		0
Total Loans	58,962		58,962		53,104
Commercial | Commercial mortgages | Substandard or Lower
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	9,913		9,913		1,861
Year two, originated, fiscal year before current fiscal year	2,584		2,584		1,210
Year three, originated, two years before current fiscal year	1,343		1,343		12,552
Year four, originated, three years before current fiscal year	11,041		11,041		2,909
Year five, originated, four years before current fiscal year	1,249		1,249		3,573
Prior	4,846		4,846		1,209
Revolving loans amortized cost basis	0		0		0
Revolving loans converted to term	15,471		15,471		569
Total Loans	46,447		46,447		23,883
Commercial | Construction
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	384,438		384,438		448,581
Year two, originated, fiscal year before current fiscal year	402,114		402,114		303,819
Year three, originated, two years before current fiscal year	173,449		173,449		124,597
Year four, originated, three years before current fiscal year	29,833		29,833		9,502
Year five, originated, four years before current fiscal year	2,566		2,566		26,553
Prior	9,241		9,241		7,539
Revolving loans amortized cost basis	0		0		0
Revolving loans converted to term	41,927		41,927		123,458
Total Loans	1,043,568	1,028,203	1,043,568	1,028,203	1,044,049
Year one, current fiscal year charge offs			0
Year two, current fiscal year charge offs			0
Year three, current fiscal year charge offs			0
Year four, current fiscal year charge offs			0
Year five, current fiscal year charge offs			0
Prior year charge offs			0
Revolving loans amortized cost basis charge offs			0
Revolving loans converted to term gross charge offs			0
Total charge offs	0	0	0	0
Commercial | Construction | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	361,914		361,914		448,581
Year two, originated, fiscal year before current fiscal year	387,776		387,776		299,619
Year three, originated, two years before current fiscal year	158,656		158,656		115,667
Year four, originated, three years before current fiscal year	20,879		20,879		9,319
Year five, originated, four years before current fiscal year	2,405		2,405		26,553
Prior	9,241		9,241		7,539
Revolving loans amortized cost basis	0		0		0
Revolving loans converted to term	41,362		41,362		122,116
Total Loans	982,233		982,233		1,029,394
Commercial | Construction | Special mention
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	14,239		14,239		0
Year two, originated, fiscal year before current fiscal year	14,338		14,338		0
Year three, originated, two years before current fiscal year	10,691		10,691		0
Year four, originated, three years before current fiscal year	0		0		0
Year five, originated, four years before current fiscal year	0		0		0
Prior	0		0		0
Revolving loans amortized cost basis	0		0		0
Revolving loans converted to term	0		0		581
Total Loans	39,268		39,268		581
Commercial | Construction | Substandard or Lower
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	8,285		8,285		0
Year two, originated, fiscal year before current fiscal year	0		0		4,200
Year three, originated, two years before current fiscal year	4,102		4,102		8,930
Year four, originated, three years before current fiscal year	8,954		8,954		183
Year five, originated, four years before current fiscal year	161		161		0
Prior	0		0		0
Revolving loans amortized cost basis	0		0		0
Revolving loans converted to term	565		565		761
Total Loans	22,067		22,067		14,074
Residential
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	152,336		152,336		64,500
Year two, originated, fiscal year before current fiscal year	69,160		69,160		111,237
Year three, originated, two years before current fiscal year	105,253		105,253		61,127
Year four, originated, three years before current fiscal year	58,251		58,251		37,117
Year five, originated, four years before current fiscal year	35,464		35,464		47,077
Prior	434,876		434,876		438,407
Revolving loans amortized cost basis	0		0		0
Revolving loans converted to term	0		0		0
Total Loans	855,340	758,593	855,340	758,593	759,465
Year one, current fiscal year charge offs			33
Year two, current fiscal year charge offs			0
Year three, current fiscal year charge offs			0
Year four, current fiscal year charge offs			0
Year five, current fiscal year charge offs			0
Prior year charge offs			0
Revolving loans amortized cost basis charge offs			0
Revolving loans converted to term gross charge offs			0
Total charge offs	0	0	33	186
Residential | Performing
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	152,336		152,336		64,500
Year two, originated, fiscal year before current fiscal year	68,990		68,990		110,508
Year three, originated, two years before current fiscal year	104,664		104,664		60,625
Year four, originated, three years before current fiscal year	57,762		57,762		36,118
Year five, originated, four years before current fiscal year	34,205		34,205		45,859
Prior	431,381		431,381		434,175
Revolving loans amortized cost basis	0		0		0
Revolving loans converted to term	0		0		0
Total Loans	849,338		849,338		751,785
Residential | Nonperforming
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	0		0		0
Year two, originated, fiscal year before current fiscal year	170		170		729
Year three, originated, two years before current fiscal year	589		589		502
Year four, originated, three years before current fiscal year	489		489		999
Year five, originated, four years before current fiscal year	1,259		1,259		1,218
Prior	3,495		3,495		4,232
Revolving loans amortized cost basis	0		0		0
Revolving loans converted to term	0		0		0
Total Loans	6,002		6,002		7,680
Consumer
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	251,967		251,967		595,158
Year two, originated, fiscal year before current fiscal year	598,183		598,183		195,397
Year three, originated, two years before current fiscal year	164,642		164,642		126,806
Year four, originated, three years before current fiscal year	108,149		108,149		54,449
Year five, originated, four years before current fiscal year	47,087		47,087		220,518
Prior	256,796		256,796		71,478
Revolving loans amortized cost basis	524,758		524,758		541,563
Revolving loans converted to term	5,500		5,500		5,561
Total Loans	1,957,082	1,677,128	1,957,082	1,677,128	1,810,930
Year one, current fiscal year charge offs			787
Year two, current fiscal year charge offs			10,716
Year three, current fiscal year charge offs			3,174
Year four, current fiscal year charge offs			235
Year five, current fiscal year charge offs			142
Prior year charge offs			320
Revolving loans amortized cost basis charge offs			0
Revolving loans converted to term gross charge offs			0
Total charge offs	5,872	$ 1,834	15,374	$ 4,062
Consumer | Performing
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	251,967		251,967		595,158
Year two, originated, fiscal year before current fiscal year	598,183		598,183		195,397
Year three, originated, two years before current fiscal year	164,642		164,642		126,456
Year four, originated, three years before current fiscal year	107,950		107,950		54,449
Year five, originated, four years before current fiscal year	47,046		47,046		220,039
Prior	256,796		256,796		71,478
Revolving loans amortized cost basis	523,391		523,391		540,308
Revolving loans converted to term	5,188		5,188		5,232
Total Loans	1,955,163		1,955,163		1,808,517
Consumer | Nonperforming
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	0		0		0
Year two, originated, fiscal year before current fiscal year	0		0		0
Year three, originated, two years before current fiscal year	0		0		350
Year four, originated, three years before current fiscal year	199		199		0
Year five, originated, four years before current fiscal year	41		41		479
Prior	0		0		0
Revolving loans amortized cost basis	1,367		1,367		1,255
Revolving loans converted to term	312		312		329
Total Loans	$ 1,919		$ 1,919		$ 2,413