ALLOWANCE FOR CREDIT LOSSES AND CREDIT QUALITY INFORMATION - Credit Quality Indicators (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021	Mar. 31, 2021
Financing Receivable, Credit Quality Indicator [Line Items]
Total Loans	$ 11,329,528	$ 7,882,055	$ 8,569,142
Commercial | Commercial and industrial
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	210,302	605,339
Year two, originated, fiscal year before current fiscal year	798,438	436,055
Year three, originated, two years before current fiscal year	560,241	386,061
Year four, originated, three years before current fiscal year	434,824	303,448
Year five, originated, four years before current fiscal year	371,269	159,343
Prior	364,106	171,029
Revolving loans amortized cost basis	8,214	5,580
Revolving loans converted to term	236,733	203,464
Total Loans	2,984,127	2,270,319	2,663,472
Gross loans	2,493,528	1,918,043
Commercial | Commercial and industrial | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	199,414	556,896
Year two, originated, fiscal year before current fiscal year	739,112	420,698
Year three, originated, two years before current fiscal year	519,388	329,354
Year four, originated, three years before current fiscal year	326,303	273,345
Year five, originated, four years before current fiscal year	337,575	139,800
Prior	307,901	148,809
Revolving loans amortized cost basis	8,089	5,551
Revolving loans converted to term	207,778	176,006
Total Loans	2,645,560	2,050,459
Commercial | Commercial and industrial | Special mention
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	0	35,910
Year two, originated, fiscal year before current fiscal year	40,972	949
Year three, originated, two years before current fiscal year	24,202	3,052
Year four, originated, three years before current fiscal year	27,509	1,057
Year five, originated, four years before current fiscal year	1,034	429
Prior	1,601	15,299
Revolving loans amortized cost basis	0	0
Revolving loans converted to term	20,136	17,545
Total Loans	115,454	74,241
Commercial | Commercial and industrial | Substandard or Lower
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	10,888	12,533
Year two, originated, fiscal year before current fiscal year	18,354	14,408
Year three, originated, two years before current fiscal year	16,651	53,655
Year four, originated, three years before current fiscal year	81,012	29,046
Year five, originated, four years before current fiscal year	32,660	19,114
Prior	54,604	6,921
Revolving loans amortized cost basis	125	29
Revolving loans converted to term	8,819	9,913
Total Loans	223,113	145,619
Commercial | Owner-occupied commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	55,073	309,286
Year two, originated, fiscal year before current fiscal year	412,446	208,223
Year three, originated, two years before current fiscal year	334,878	179,202
Year four, originated, three years before current fiscal year	277,760	77,835
Year five, originated, four years before current fiscal year	144,752	142,277
Prior	500,049	280,687
Revolving loans amortized cost basis	0	0
Revolving loans converted to term	147,869	144,197
Total Loans	1,872,827	1,341,707	1,333,989
Gross loans	1,872,827	1,341,707
Commercial | Owner-occupied commercial | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	55,073	305,156
Year two, originated, fiscal year before current fiscal year	403,732	189,128
Year three, originated, two years before current fiscal year	312,617	172,503
Year four, originated, three years before current fiscal year	268,920	67,526
Year five, originated, four years before current fiscal year	131,476	136,697
Prior	472,999	262,629
Revolving loans amortized cost basis	0	0
Revolving loans converted to term	132,633	128,188
Total Loans	1,777,450	1,261,827
Commercial | Owner-occupied commercial | Special mention
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	0	938
Year two, originated, fiscal year before current fiscal year	3,449	5,359
Year three, originated, two years before current fiscal year	2,921	2,561
Year four, originated, three years before current fiscal year	2,526	891
Year five, originated, four years before current fiscal year	1,298	0
Prior	6,813	7,019
Revolving loans amortized cost basis	0	0
Revolving loans converted to term	47	10,543
Total Loans	17,054	27,311
Commercial | Owner-occupied commercial | Substandard or Lower
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	0	3,192
Year two, originated, fiscal year before current fiscal year	5,265	13,736
Year three, originated, two years before current fiscal year	19,340	4,138
Year four, originated, three years before current fiscal year	6,314	9,418
Year five, originated, four years before current fiscal year	11,978	5,580
Prior	20,237	11,039
Revolving loans amortized cost basis	0	0
Revolving loans converted to term	15,189	5,466
Total Loans	78,323	52,569
Commercial | Commercial mortgages
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	70,519	418,587
Year two, originated, fiscal year before current fiscal year	725,885	286,698
Year three, originated, two years before current fiscal year	592,825	221,100
Year four, originated, three years before current fiscal year	635,377	137,452
Year five, originated, four years before current fiscal year	298,861	243,705
Prior	848,905	383,997
Revolving loans amortized cost basis	0	0
Revolving loans converted to term	188,870	189,971
Total Loans	3,361,242	1,881,510	1,975,966
Gross loans	3,361,242	1,881,510
Commercial | Commercial mortgages | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	70,519	416,149
Year two, originated, fiscal year before current fiscal year	719,997	280,889
Year three, originated, two years before current fiscal year	568,289	217,311
Year four, originated, three years before current fiscal year	615,715	134,477
Year five, originated, four years before current fiscal year	275,125	229,863
Prior	791,959	368,527
Revolving loans amortized cost basis	0	0
Revolving loans converted to term	186,784	187,396
Total Loans	3,228,388	1,834,612
Commercial | Commercial mortgages | Special mention
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	0	0
Year two, originated, fiscal year before current fiscal year	2,996	4,185
Year three, originated, two years before current fiscal year	15,918	0
Year four, originated, three years before current fiscal year	12,596	861
Year five, originated, four years before current fiscal year	10,547	11,588
Prior	39,958	1,385
Revolving loans amortized cost basis	0	0
Revolving loans converted to term	2,086	2,097
Total Loans	84,101	20,116
Commercial | Commercial mortgages | Substandard or Lower
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	0	2,438
Year two, originated, fiscal year before current fiscal year	2,892	1,624
Year three, originated, two years before current fiscal year	8,618	3,789
Year four, originated, three years before current fiscal year	7,066	2,114
Year five, originated, four years before current fiscal year	13,189	2,254
Prior	16,988	14,085
Revolving loans amortized cost basis	0	0
Revolving loans converted to term	0	478
Total Loans	48,753	26,782
Commercial | Construction
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	103,427	260,975
Year two, originated, fiscal year before current fiscal year	368,352	195,269
Year three, originated, two years before current fiscal year	188,214	87,290
Year four, originated, three years before current fiscal year	69,307	39,585
Year five, originated, four years before current fiscal year	80,948	2,313
Prior	15,179	11,297
Revolving loans amortized cost basis	0	0
Revolving loans converted to term	98,463	90,484
Total Loans	923,890	687,213	784,101
Gross loans	923,890	687,213
Commercial | Construction | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	101,402	248,053
Year two, originated, fiscal year before current fiscal year	354,624	195,269
Year three, originated, two years before current fiscal year	186,593	84,868
Year four, originated, three years before current fiscal year	69,089	39,585
Year five, originated, four years before current fiscal year	80,948	2,223
Prior	15,091	11,297
Revolving loans amortized cost basis	0	0
Revolving loans converted to term	96,818	88,839
Total Loans	904,565	670,134
Commercial | Construction | Special mention
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	0	0
Year two, originated, fiscal year before current fiscal year	602	0
Year three, originated, two years before current fiscal year	0	0
Year four, originated, three years before current fiscal year	0	0
Year five, originated, four years before current fiscal year	0	0
Prior	0	0
Revolving loans amortized cost basis	0	0
Revolving loans converted to term	0	0
Total Loans	602	0
Commercial | Construction | Substandard or Lower
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	2,025	12,922
Year two, originated, fiscal year before current fiscal year	13,126	0
Year three, originated, two years before current fiscal year	1,621	2,422
Year four, originated, three years before current fiscal year	218	0
Year five, originated, four years before current fiscal year	0	90
Prior	88	0
Revolving loans amortized cost basis	0	0
Revolving loans converted to term	1,645	1,645
Total Loans	18,723	17,079
Commercial | PPP loans
Financing Receivable, Credit Quality Indicator [Line Items]
Gross loans	8,500	31,500
Residential
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	8,102	59,977
Year two, originated, fiscal year before current fiscal year	107,827	28,538
Year three, originated, two years before current fiscal year	68,776	13,570
Year four, originated, three years before current fiscal year	43,306	32,871
Year five, originated, four years before current fiscal year	63,215	45,032
Prior	514,100	362,745
Revolving loans amortized cost basis	0	0
Revolving loans converted to term	0	0
Total Loans	805,326	542,733	671,580
Gross loans	809,610	546,667
Residential | Performing
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	8,102	59,977
Year two, originated, fiscal year before current fiscal year	107,827	28,426
Year three, originated, two years before current fiscal year	68,665	12,526
Year four, originated, three years before current fiscal year	42,279	32,871
Year five, originated, four years before current fiscal year	63,215	44,969
Prior	508,814	358,964
Revolving loans amortized cost basis	0	0
Revolving loans converted to term	0	0
Total Loans	798,902	537,733
Residential | Nonperforming
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	0	0
Year two, originated, fiscal year before current fiscal year	0	112
Year three, originated, two years before current fiscal year	111	1,044
Year four, originated, three years before current fiscal year	1,027	0
Year five, originated, four years before current fiscal year	0	63
Prior	5,286	3,781
Revolving loans amortized cost basis	0	0
Revolving loans converted to term	0	0
Total Loans	6,424	5,000
Consumer
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	100,753	219,918
Year two, originated, fiscal year before current fiscal year	239,198	170,069
Year three, originated, two years before current fiscal year	152,040	74,048
Year four, originated, three years before current fiscal year	64,709	204,119
Year five, originated, four years before current fiscal year	225,119	39,184
Prior	105,028	60,952
Revolving loans amortized cost basis	489,660	384,373
Revolving loans converted to term	5,609	5,910
Total Loans	1,382,116	1,158,573	$ 1,140,034
Gross loans	1,382,116	1,158,573
Consumer | Performing
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	100,753	219,918
Year two, originated, fiscal year before current fiscal year	239,198	169,922
Year three, originated, two years before current fiscal year	151,851	74,048
Year four, originated, three years before current fiscal year	64,709	203,519
Year five, originated, four years before current fiscal year	224,593	39,113
Prior	105,028	60,952
Revolving loans amortized cost basis	488,139	382,718
Revolving loans converted to term	5,125	5,364
Total Loans	1,379,396	1,155,554
Consumer | Nonperforming
Financing Receivable, Credit Quality Indicator [Line Items]
Year one, originated, current fiscal year	0	0
Year two, originated, fiscal year before current fiscal year	0	147
Year three, originated, two years before current fiscal year	189	0
Year four, originated, three years before current fiscal year	0	600
Year five, originated, four years before current fiscal year	526	71
Prior	0	0
Revolving loans amortized cost basis	1,521	1,655
Revolving loans converted to term	484	546
Total Loans	$ 2,720	$ 3,019