CREDIT QUALITY ASSESSMENT - Allowance for Credit or Loan Losses by Respective Loan Portfolio Segment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of year	$ 136,242	$ 109,145	$ 165,367
Provision/ (credit) for credit losses - loans	(13,894)	26,680	(45,556)
Loans charge-offs	(2,614)	(1,105)	(12,313)
Loans recoveries	1,131	1,522	1,647
Net (charge-offs)/ recoveries	(1,483)	417	(10,666)
Balance at period end	120,865	136,242	109,145
Total loans	$ 11,366,989	$ 11,396,706
Allowance for credit losses on loans to total loans ratio	1.06%	1.20%
Average loans	$ 11,354,227	$ 10,638,882
Net charge-offs/ (recoveries) to average loans	0.01%	0.00%
Balance of loans individually evaluated for credit loss	$ 88,168	$ 26,197
Allowance for credit losses related to loans evaluated individually	$ 24,000	$ 6,902
Individual allowance to loans evaluated individually ratio	27.22%	26.35%
Contractual balance of individually evaluated loans	$ 91,105	$ 29,475
Balance of loans collectively evaluated for credit loss	11,278,821	11,370,509
Allowance for credit losses related to loans evaluated collectively	$ 96,865	$ 129,340
Collective allowance to loans evaluated collectively ratio	0.86%	1.14%
Commercial Investor R/E
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Loans charge-offs	$ 0	$ 0
Total loans	5,104,425	5,130,094
Commercial Owner- Occupied R/E
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Loans charge-offs	0	0
Total loans	1,755,235	1,775,037
Commercial AD&C
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Loans charge-offs	0	0
Total loans	988,967	1,090,028
Residential Mortgage
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Loans charge-offs	(160)	(155)
Total loans	1,474,521	1,287,933
Residential Construction
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Loans charge-offs	0	0
Total loans	121,419	224,772
Commercial Real Estate | Commercial Investor R/E
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of year	64,737	45,289
Provision/ (credit) for credit losses - loans	(3,323)	19,128
Loans charge-offs	0	0
Loans recoveries	25	320
Net (charge-offs)/ recoveries	25	320
Balance at period end	61,439	64,737	45,289
Total loans	$ 5,104,425	$ 5,130,094
Allowance for credit losses on loans to total loans ratio	1.20%	1.26%
Average loans	$ 5,133,279	$ 4,681,607
Net charge-offs/ (recoveries) to average loans	0.00%	(0.01%)
Balance of loans individually evaluated for credit loss	$ 72,218	$ 9,943
Allowance for credit losses related to loans evaluated individually	$ 15,353	$ 134
Individual allowance to loans evaluated individually ratio	21.26%	1.35%
Contractual balance of individually evaluated loans	$ 72,712	$ 10,882
Balance of loans collectively evaluated for credit loss	5,032,207	5,120,151
Allowance for credit losses related to loans evaluated collectively	$ 46,086	$ 64,603
Collective allowance to loans evaluated collectively ratio	0.92%	1.26%
Commercial Real Estate | Commercial Owner- Occupied R/E
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of year	$ 11,646	$ 11,687
Provision/ (credit) for credit losses - loans	(4,215)	(90)
Loans charge-offs	0	0
Loans recoveries	105	49
Net (charge-offs)/ recoveries	105	49
Balance at period end	7,536	11,646	11,687
Total loans	$ 1,755,235	$ 1,775,037
Allowance for credit losses on loans to total loans ratio	0.43%	0.66%
Average loans	$ 1,766,839	$ 1,730,293
Net charge-offs/ (recoveries) to average loans	(0.01%)	0.00%
Balance of loans individually evaluated for credit loss	$ 4,640	$ 6,155
Allowance for credit losses related to loans evaluated individually	$ 1,159	$ 1,261
Individual allowance to loans evaluated individually ratio	24.98%	20.49%
Contractual balance of individually evaluated loans	$ 5,623	$ 6,849
Balance of loans collectively evaluated for credit loss	1,750,595	1,768,882
Allowance for credit losses related to loans evaluated collectively	$ 6,377	$ 10,385
Collective allowance to loans evaluated collectively ratio	0.36%	0.59%
Commercial Real Estate | Commercial AD&C
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of year	$ 18,646	$ 20,322
Provision/ (credit) for credit losses - loans	(10,359)	(1,676)
Loans charge-offs	0	0
Loans recoveries	0	0
Net (charge-offs)/ recoveries	0	0
Balance at period end	8,287	18,646	20,322
Total loans	$ 988,967	$ 1,090,028
Allowance for credit losses on loans to total loans ratio	0.84%	1.71%
Average loans	$ 1,023,669	$ 1,112,936
Net charge-offs/ (recoveries) to average loans	0.00%	0.00%
Balance of loans individually evaluated for credit loss	$ 1,259	$ 0
Allowance for credit losses related to loans evaluated individually	$ 102	$ 0
Individual allowance to loans evaluated individually ratio	8.10%	0.00%
Contractual balance of individually evaluated loans	$ 1,270	$ 0
Balance of loans collectively evaluated for credit loss	987,708	1,090,028
Allowance for credit losses related to loans evaluated collectively	$ 8,185	$ 18,646
Collective allowance to loans evaluated collectively ratio	0.83%	1.71%
Commercial Business
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Total loans	$ 9,353,507	$ 9,451,044
Commercial Business | Commercial Business
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of year	28,027	23,170
Provision/ (credit) for credit losses - loans	4,051	4,774
Loans charge-offs	(449)	(716)
Loans recoveries	303	799
Net (charge-offs)/ recoveries	(146)	83
Balance at period end	31,932	28,027	23,170
Total loans	$ 1,504,880	$ 1,455,885
Allowance for credit losses on loans to total loans ratio	2.12%	1.93%
Average loans	$ 1,440,382	$ 1,351,906
Net charge-offs/ (recoveries) to average loans	0.01%	(0.01%)
Balance of loans individually evaluated for credit loss	$ 10,051	$ 8,274
Allowance for credit losses related to loans evaluated individually	$ 7,386	$ 5,507
Individual allowance to loans evaluated individually ratio	73.49%	66.56%
Contractual balance of individually evaluated loans	$ 11,500	$ 9,893
Balance of loans collectively evaluated for credit loss	1,494,829	1,447,611
Allowance for credit losses related to loans evaluated collectively	$ 24,546	$ 22,520
Collective allowance to loans evaluated collectively ratio	1.64%	1.56%
Residential Real Estate | Residential Mortgage
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of year	$ 9,424	$ 5,384
Provision/ (credit) for credit losses - loans	(488)	4,093
Loans charge-offs	(160)	(155)
Loans recoveries	114	102
Net (charge-offs)/ recoveries	(46)	(53)
Balance at period end	8,890	9,424	5,384
Total loans	$ 1,474,521	$ 1,287,933
Allowance for credit losses on loans to total loans ratio	0.60%	0.73%
Average loans	$ 1,380,496	$ 1,117,053
Net charge-offs/ (recoveries) to average loans	0.00%	0.00%
Balance of loans individually evaluated for credit loss	$ 0	$ 1,487
Allowance for credit losses related to loans evaluated individually	$ 0	$ 0
Individual allowance to loans evaluated individually ratio	0.00%	0.00%
Contractual balance of individually evaluated loans	$ 0	$ 1,487
Balance of loans collectively evaluated for credit loss	1,474,521	1,286,446
Allowance for credit losses related to loans evaluated collectively	$ 8,890	$ 9,424
Collective allowance to loans evaluated collectively ratio	0.60%	0.73%
Residential Real Estate | Residential Construction
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of year	$ 1,337	$ 1,048
Provision/ (credit) for credit losses - loans	(608)	281
Loans charge-offs	0	0
Loans recoveries	0	8
Net (charge-offs)/ recoveries	0	8
Balance at period end	729	1,337	1,048
Total loans	$ 121,419	$ 224,772
Allowance for credit losses on loans to total loans ratio	0.60%	0.59%
Average loans	$ 187,599	$ 221,341
Net charge-offs/ (recoveries) to average loans	0.00%	0.00%
Balance of loans individually evaluated for credit loss	$ 0	$ 0
Allowance for credit losses related to loans evaluated individually	$ 0	$ 0
Individual allowance to loans evaluated individually ratio	0.00%	0.00%
Contractual balance of individually evaluated loans	$ 0	$ 0
Balance of loans collectively evaluated for credit loss	121,419	224,772
Allowance for credit losses related to loans evaluated collectively	$ 729	$ 1,337
Collective allowance to loans evaluated collectively ratio	0.60%	0.59%
Consumer
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of year	$ 2,425	$ 2,245
Provision/ (credit) for credit losses - loans	1,048	170
Loans charge-offs	(2,005)	(234)
Loans recoveries	584	244
Net (charge-offs)/ recoveries	(1,421)	10
Balance at period end	2,052	2,425	$ 2,245
Total loans	$ 417,542	$ 432,957
Allowance for credit losses on loans to total loans ratio	0.49%	0.56%
Average loans	$ 421,963	$ 423,746
Net charge-offs/ (recoveries) to average loans	0.34%	0.00%
Balance of loans individually evaluated for credit loss	$ 0	$ 338
Allowance for credit losses related to loans evaluated individually	$ 0	$ 0
Individual allowance to loans evaluated individually ratio	0.00%	0.00%
Contractual balance of individually evaluated loans	$ 0	$ 364
Balance of loans collectively evaluated for credit loss	417,542	432,619
Allowance for credit losses related to loans evaluated collectively	$ 2,052	$ 2,425
Collective allowance to loans evaluated collectively ratio	0.49%	0.56%