CREDIT QUALITY ASSESSMENT - Allowance for Credit or Loan Losses by Respective Loan Portfolio Segment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of year	$ 109,145	$ 165,367	$ 56,132
Provision/ (credit) for credit losses - loans	26,680	(45,556)	85,669
Loans charge-offs	(1,105)	(12,313)	(1,819)
Loans recoveries	1,522	1,647	1,012
Net (charge-offs)/ recoveries	417	(10,666)	(807)
Balance at period end	136,242	109,145	165,367
Total loans	$ 11,396,706	$ 9,967,091
Allowance for credit losses on loans to total loans ratio	1.20%	1.10%
Average loans	$ 10,638,882	$ 10,034,866
Net charge-offs/ (recoveries) to average loans	0.00%	0.11%
Total individually evaluated loans:	$ 26,197	$ 33,534
Allowance for credit losses related to loans evaluated individually	$ 6,902	$ 6,593
Individual allowance to loans evaluated individually ratio	26.35%	19.66%
Balance of loans collectively evaluated for credit loss	$ 11,370,509	$ 9,933,557
Allowance for credit losses related to loans evaluated collectively	$ 129,340	$ 102,552
Collective allowance to loans evaluated collectively ratio	1.14%	1.03%
Commercial investor real estate
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Loans charge-offs	$ 0	$ (5,802)
Total loans	5,130,094	4,141,346
Commercial owner-occupied real estate
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Loans charge-offs	0	(136)
Total loans	1,775,037	1,690,881
Commercial AD&C
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Loans charge-offs	0	(2,007)
Total loans	1,090,028	1,088,094
Residential mortgage
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Loans charge-offs	(155)	0
Total loans	1,287,933	937,570
Residential construction
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Loans charge-offs	0	0
Total loans	224,772	197,652
Commercial real estate: | Commercial investor real estate
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of year	45,289	57,404
Provision/ (credit) for credit losses - loans	19,128	(6,598)
Loans charge-offs	0	(5,802)
Loans recoveries	320	285
Net (charge-offs)/ recoveries	320	(5,517)
Balance at period end	64,737	45,289	57,404
Total loans	$ 5,130,094	$ 4,141,346
Allowance for credit losses on loans to total loans ratio	1.26%	1.09%
Average loans	$ 4,681,607	$ 3,689,769
Net charge-offs/ (recoveries) to average loans	(0.01%)	0.15%
Total individually evaluated loans:	$ 9,943	$ 12,489
Allowance for credit losses related to loans evaluated individually	$ 134	$ 213
Individual allowance to loans evaluated individually ratio	1.35%	1.71%
Balance of loans collectively evaluated for credit loss	$ 5,120,151	$ 4,128,857
Allowance for credit losses related to loans evaluated collectively	$ 64,603	$ 45,076
Collective allowance to loans evaluated collectively ratio	1.26%	1.09%
Commercial real estate: | Commercial owner-occupied real estate
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of year	$ 11,687	$ 20,061
Provision/ (credit) for credit losses - loans	(90)	(8,238)
Loans charge-offs	0	(136)
Loans recoveries	49	0
Net (charge-offs)/ recoveries	49	(136)
Balance at period end	11,646	11,687	20,061
Total loans	$ 1,775,037	$ 1,690,881
Allowance for credit losses on loans to total loans ratio	0.66%	0.69%
Average loans	$ 1,730,293	$ 1,661,015
Net charge-offs/ (recoveries) to average loans	0.00%	0.01%
Total individually evaluated loans:	$ 6,155	$ 9,306
Allowance for credit losses related to loans evaluated individually	$ 1,261	$ 79
Individual allowance to loans evaluated individually ratio	20.49%	0.85%
Balance of loans collectively evaluated for credit loss	$ 1,768,882	$ 1,681,575
Allowance for credit losses related to loans evaluated collectively	$ 10,385	$ 11,608
Collective allowance to loans evaluated collectively ratio	0.59%	0.69%
Commercial real estate: | Commercial AD&C
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of year	$ 20,322	$ 22,157
Provision/ (credit) for credit losses - loans	(1,676)	172
Loans charge-offs	0	(2,007)
Loans recoveries	0	0
Net (charge-offs)/ recoveries	0	(2,007)
Balance at period end	18,646	20,322	22,157
Total loans	$ 1,090,028	$ 1,088,094
Allowance for credit losses on loans to total loans ratio	1.71%	1.87%
Average loans	$ 1,112,936	$ 1,110,420
Net charge-offs/ (recoveries) to average loans	0.00%	0.18%
Total individually evaluated loans:	$ 0	$ 650
Allowance for credit losses related to loans evaluated individually	$ 0	$ 504
Individual allowance to loans evaluated individually ratio	0.00%	77.54%
Balance of loans collectively evaluated for credit loss	$ 1,090,028	$ 1,087,444
Allowance for credit losses related to loans evaluated collectively	$ 18,646	$ 19,818
Collective allowance to loans evaluated collectively ratio	1.71%	1.82%
Commercial Business
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Total loans	$ 9,451,044	$ 8,402,155
Total individually evaluated loans:	8,274	9,033
Allowance for credit losses related to loans evaluated individually	5,507	5,797
Commercial Business | Commercial business
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of year	23,170	46,806
Provision/ (credit) for credit losses - loans	4,774	(20,132)
Loans charge-offs	(716)	(4,069)
Loans recoveries	799	565
Net (charge-offs)/ recoveries	83	(3,504)
Balance at period end	28,027	23,170	46,806
Total loans	$ 1,455,885	$ 1,481,834
Allowance for credit losses on loans to total loans ratio	1.93%	1.56%
Average loans	$ 1,351,906	$ 1,952,537
Net charge-offs/ (recoveries) to average loans	(0.01%)	0.18%
Total individually evaluated loans:	$ 8,274	$ 9,033
Allowance for credit losses related to loans evaluated individually	$ 5,507	$ 5,797
Individual allowance to loans evaluated individually ratio	66.56%	64.18%
Balance of loans collectively evaluated for credit loss	$ 1,447,611	$ 1,472,801
Allowance for credit losses related to loans evaluated collectively	$ 22,520	$ 17,373
Collective allowance to loans evaluated collectively ratio	1.56%	1.18%
Residential real estate: | Residential mortgage
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of year	$ 5,384	$ 11,295
Provision/ (credit) for credit losses - loans	4,093	(6,321)
Loans charge-offs	(155)	0
Loans recoveries	102	410
Net (charge-offs)/ recoveries	(53)	410
Balance at period end	9,424	5,384	11,295
Total loans	$ 1,287,933	$ 937,570
Allowance for credit losses on loans to total loans ratio	0.73%	0.57%
Average loans	$ 1,117,053	$ 979,754
Net charge-offs/ (recoveries) to average loans	0.00%	(0.04%)
Total individually evaluated loans:	$ 1,487	$ 1,704
Allowance for credit losses related to loans evaluated individually	$ 0	$ 0
Individual allowance to loans evaluated individually ratio	0.00%	0.00%
Balance of loans collectively evaluated for credit loss	$ 1,286,446	$ 935,866
Allowance for credit losses related to loans evaluated collectively	$ 9,424	$ 5,384
Collective allowance to loans evaluated collectively ratio	0.73%	0.58%
Residential real estate: | Residential construction
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of year	$ 1,048	$ 1,502
Provision/ (credit) for credit losses - loans	281	(459)
Loans charge-offs	0	0
Loans recoveries	8	5
Net (charge-offs)/ recoveries	8	5
Balance at period end	1,337	1,048	1,502
Total loans	$ 224,772	$ 197,652
Allowance for credit losses on loans to total loans ratio	0.59%	0.53%
Average loans	$ 221,341	$ 178,171
Net charge-offs/ (recoveries) to average loans	0.00%	0.00%
Total individually evaluated loans:	$ 0	$ 0
Allowance for credit losses related to loans evaluated individually	$ 0	$ 0
Individual allowance to loans evaluated individually ratio	0.00%	0.00%
Balance of loans collectively evaluated for credit loss	$ 224,772	$ 197,652
Allowance for credit losses related to loans evaluated collectively	$ 1,337	$ 1,048
Collective allowance to loans evaluated collectively ratio	0.59%	0.53%
Consumer
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of year	$ 2,245	$ 6,142
Provision/ (credit) for credit losses - loans	170	(3,980)
Loans charge-offs	(234)	(299)
Loans recoveries	244	382
Net (charge-offs)/ recoveries	10	83
Balance at period end	2,425	2,245	$ 6,142
Total loans	$ 432,957	$ 429,714
Allowance for credit losses on loans to total loans ratio	0.56%	0.52%
Average loans	$ 423,746	$ 463,200
Net charge-offs/ (recoveries) to average loans	0.00%	(0.02%)
Total individually evaluated loans:	$ 338	$ 352
Allowance for credit losses related to loans evaluated individually	$ 0	$ 0
Individual allowance to loans evaluated individually ratio	0.00%	0.00%
Balance of loans collectively evaluated for credit loss	$ 432,619	$ 429,362
Allowance for credit losses related to loans evaluated collectively	$ 2,425	$ 2,245
Collective allowance to loans evaluated collectively ratio	0.56%	0.52%