CREDIT QUALITY ASSESSMENT - Credit Quality of Loan Portfolio, New (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Financing Receivable, Past Due [Line Items]
Total loans	$ 11,218,813	$ 9,967,091
Performing loans:
Financing Receivable, Past Due [Line Items]
Total loans	11,174,352	9,918,281
Non-performing loans:
Financing Receivable, Past Due [Line Items]
Non-accrual loans	40,217	46,086
Loans greater than 90 days past due	2,167	557
Restructured loans	2,077	2,167
Total loans	44,461	48,810
Current | Performing loans:
Financing Receivable, Past Due [Line Items]
Total loans	11,123,607	9,901,309
30-59 days | Performing loans:
Financing Receivable, Past Due [Line Items]
Total loans	33,278	12,475
60-89 days | Performing loans:
Financing Receivable, Past Due [Line Items]
Total loans	17,467	4,497
Commercial investor real estate
Financing Receivable, Past Due [Line Items]
Total loans	5,066,843	4,141,346
Commercial owner-occupied real estate
Financing Receivable, Past Due [Line Items]
Total loans	1,743,724	1,690,881
Commercial AD&C
Financing Receivable, Past Due [Line Items]
Total loans	1,143,783	1,088,094
Residential mortgage
Financing Receivable, Past Due [Line Items]
Total loans	1,218,552	937,570
Residential construction
Financing Receivable, Past Due [Line Items]
Total loans	229,243	197,652
Commercial real estate: | Commercial investor real estate
Financing Receivable, Past Due [Line Items]
Total loans	5,066,843	4,141,346
Commercial real estate: | Commercial investor real estate | Performing loans:
Financing Receivable, Past Due [Line Items]
Total loans	5,052,805	4,128,857
Commercial real estate: | Commercial investor real estate | Non-performing loans:
Financing Receivable, Past Due [Line Items]
Non-accrual loans	14,038	12,489
Loans greater than 90 days past due	0	0
Restructured loans	0	0
Total loans	14,038	12,489
Commercial real estate: | Commercial investor real estate | Current | Performing loans:
Financing Receivable, Past Due [Line Items]
Total loans	5,033,645	4,127,009
Commercial real estate: | Commercial investor real estate | 30-59 days | Performing loans:
Financing Receivable, Past Due [Line Items]
Total loans	15,615	1,656
Commercial real estate: | Commercial investor real estate | 60-89 days | Performing loans:
Financing Receivable, Past Due [Line Items]
Total loans	3,545	192
Commercial real estate: | Commercial owner-occupied real estate
Financing Receivable, Past Due [Line Items]
Total loans	1,743,724	1,690,881
Commercial real estate: | Commercial owner-occupied real estate | Performing loans:
Financing Receivable, Past Due [Line Items]
Total loans	1,737,430	1,681,575
Commercial real estate: | Commercial owner-occupied real estate | Non-performing loans:
Financing Receivable, Past Due [Line Items]
Non-accrual loans	6,294	9,306
Loans greater than 90 days past due	0	0
Restructured loans	0	0
Total loans	6,294	9,306
Commercial real estate: | Commercial owner-occupied real estate | Current | Performing loans:
Financing Receivable, Past Due [Line Items]
Total loans	1,729,541	1,680,635
Commercial real estate: | Commercial owner-occupied real estate | 30-59 days | Performing loans:
Financing Receivable, Past Due [Line Items]
Total loans	1,859	86
Commercial real estate: | Commercial owner-occupied real estate | 60-89 days | Performing loans:
Financing Receivable, Past Due [Line Items]
Total loans	6,030	854
Commercial real estate: | Commercial AD&C
Financing Receivable, Past Due [Line Items]
Total loans	1,143,783	1,088,094
Commercial real estate: | Commercial AD&C | Performing loans:
Financing Receivable, Past Due [Line Items]
Total loans	1,143,783	1,087,444
Commercial real estate: | Commercial AD&C | Non-performing loans:
Financing Receivable, Past Due [Line Items]
Non-accrual loans	0	650
Loans greater than 90 days past due	0	0
Restructured loans	0	0
Total loans	0	650
Commercial real estate: | Commercial AD&C | Current | Performing loans:
Financing Receivable, Past Due [Line Items]
Total loans	1,138,204	1,085,642
Commercial real estate: | Commercial AD&C | 30-59 days | Performing loans:
Financing Receivable, Past Due [Line Items]
Total loans	2,725	1,802
Commercial real estate: | Commercial AD&C | 60-89 days | Performing loans:
Financing Receivable, Past Due [Line Items]
Total loans	2,854	0
Commercial Business
Financing Receivable, Past Due [Line Items]
Total loans	9,347,984	8,402,155
Commercial Business | Commercial business
Financing Receivable, Past Due [Line Items]
Total loans	1,393,634	1,481,834
Commercial Business | Commercial business | Performing loans:
Financing Receivable, Past Due [Line Items]
Total loans	1,383,899	1,472,801
Commercial Business | Commercial business | Non-performing loans:
Financing Receivable, Past Due [Line Items]
Non-accrual loans	7,198	8,420
Loans greater than 90 days past due	1,966	0
Restructured loans	571	613
Total loans	9,735	9,033
Commercial Business | Commercial business | Current | Performing loans:
Financing Receivable, Past Due [Line Items]
Total loans	1,383,499	1,471,669
Commercial Business | Commercial business | 30-59 days | Performing loans:
Financing Receivable, Past Due [Line Items]
Total loans	139	753
Commercial Business | Commercial business | 60-89 days | Performing loans:
Financing Receivable, Past Due [Line Items]
Total loans	261	379
Residential real estate: | Residential mortgage
Financing Receivable, Past Due [Line Items]
Total loans	1,218,552	937,570
Residential real estate: | Residential mortgage | Performing loans:
Financing Receivable, Past Due [Line Items]
Total loans	1,209,365	927,018
Residential real estate: | Residential mortgage | Non-performing loans:
Financing Receivable, Past Due [Line Items]
Non-accrual loans	7,514	8,441
Loans greater than 90 days past due	167	557
Restructured loans	1,506	1,554
Total loans	9,187	10,552
Residential real estate: | Residential mortgage | Current | Performing loans:
Financing Receivable, Past Due [Line Items]
Total loans	1,195,498	919,199
Residential real estate: | Residential mortgage | 30-59 days | Performing loans:
Financing Receivable, Past Due [Line Items]
Total loans	9,251	5,157
Residential real estate: | Residential mortgage | 60-89 days | Performing loans:
Financing Receivable, Past Due [Line Items]
Total loans	4,616	2,662
Residential real estate: | Residential construction
Financing Receivable, Past Due [Line Items]
Total loans	229,243	197,652
Residential real estate: | Residential construction | Performing loans:
Financing Receivable, Past Due [Line Items]
Total loans	229,243	197,597
Residential real estate: | Residential construction | Non-performing loans:
Financing Receivable, Past Due [Line Items]
Non-accrual loans	0	55
Loans greater than 90 days past due	0	0
Restructured loans	0	0
Total loans	0	55
Residential real estate: | Residential construction | Current | Performing loans:
Financing Receivable, Past Due [Line Items]
Total loans	227,881	197,597
Residential real estate: | Residential construction | 30-59 days | Performing loans:
Financing Receivable, Past Due [Line Items]
Total loans	1,362	0
Residential real estate: | Residential construction | 60-89 days | Performing loans:
Financing Receivable, Past Due [Line Items]
Total loans	0	0
Consumer
Financing Receivable, Past Due [Line Items]
Total loans	423,034	429,714
Consumer | Performing loans:
Financing Receivable, Past Due [Line Items]
Total loans	417,827	422,989
Consumer | Non-performing loans:
Financing Receivable, Past Due [Line Items]
Non-accrual loans	5,173	6,725
Loans greater than 90 days past due	34	0
Restructured loans	0	0
Total loans	5,207	6,725
Consumer | Current | Performing loans:
Financing Receivable, Past Due [Line Items]
Total loans	415,339	419,558
Consumer | 30-59 days | Performing loans:
Financing Receivable, Past Due [Line Items]
Total loans	2,327	3,021
Consumer | 60-89 days | Performing loans:
Financing Receivable, Past Due [Line Items]
Total loans	$ 161	$ 410