BUSINESS SEGMENTS - Schedule of Income and Total Assets for Reportable Segments (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Net interest income	$ 32,149	$ 30,085	$ 95,867	$ 89,360
Noninterest income	20,211	14,416	47,354	39,171
Total income	52,360	44,501	143,221	128,531
Provision for loan and lease losses	5,150	800	30,050	2,050
Compensation and employee benefits	19,202	17,476	57,614	52,175
Premises and equipment expense	4,109	3,849	12,188	10,837
FDIC insurance expense	605	(277)	1,310	277
Other noninterest expense	4,545	5,211	14,598	14,858
Total noninterest expense	33,611	27,059	115,760	80,197
Income before income tax (benefit)/expense	18,749	17,442	27,461	48,334
Income tax (benefit)/expense	5,202	5,216	4,299	13,133
NET INCOME	13,547	12,226	23,162	35,201
Total assets at period end	5,958,107	4,925,409	5,958,107	4,925,409	$ 5,182,879
Banking [Member]
Net interest income	30,557	28,836	91,419	85,336
Noninterest income	9,451	4,561	16,036	9,991
Total income	40,008	33,397	107,455	95,327
Provision for loan and lease losses	5,150	800	30,050	2,050
Compensation and employee benefits	13,258	11,776	40,239	36,458
Premises and equipment expense	3,527	3,294	10,435	9,265
FDIC insurance expense	605	(277)	1,310	277
Other noninterest expense	2,231	2,985	7,889	8,296
Total noninterest expense	24,771	18,578	89,923	56,346
Income before income tax (benefit)/expense	15,237	14,819	17,532	38,981
Income tax (benefit)/expense	4,254	4,399	1,618	10,592
NET INCOME	10,983	10,420	15,914	28,389
Total assets at period end	5,878,481	4,840,002	5,878,481	4,840,002
Wealth Management Division [Member]
Net interest income	1,592	1,249	4,448	4,024
Noninterest income	10,760	9,855	31,318	29,180
Total income	12,352	11,104	35,766	33,204
Provision for loan and lease losses	0	0	0	0
Compensation and employee benefits	5,944	5,700	17,375	15,717
Premises and equipment expense	582	555	1,753	1,572
FDIC insurance expense	0	0	0	0
Other noninterest expense	2,314	2,226	6,709	6,562
Total noninterest expense	8,840	8,481	25,837	23,851
Income before income tax (benefit)/expense	3,512	2,623	9,929	9,353
Income tax (benefit)/expense	948	817	2,681	2,541
NET INCOME	2,564	1,806	7,248	6,812
Total assets at period end	$ 79,626	$ 85,407	$ 79,626	$ 85,407