BUSINESS SEGMENTS - Schedule of Income and Total Assets for Reportable Segments (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Net interest income	$ 31,735	$ 32,149	$ 31,971	$ 31,747	$ 30,914	$ 30,085	$ 29,268	$ 30,007	$ 127,602	$ 120,274	$ 115,163
Noninterest income									61,760	54,696	44,193
Total income									189,362	174,970	159,356
Provision for loan losses	2,350	5,150	4,900	20,000	1,950	800	1,150	100	32,400	4,000	3,550
Compensation and benefits									77,516	70,129	62,802
Premises and equipment expense									16,377	14,735	13,497
FDIC expense									1,975	277	2,443
Other noninterest expense									29,091	19,707	19,344
Total noninterest expense									157,359	108,848	101,636
Income before income tax expense	4,542	18,749	10,683	(1,971)	17,788	17,442	14,971	15,921	32,003	66,122	57,720
Income tax expense	1,512	5,202	2,441	(3,344)	5,555	5,216	3,421	4,496	5,811	18,688	13,550
Net income	3,030	$ 13,547	$ 8,242	$ 1,373	12,233	$ 12,226	$ 11,550	$ 11,425	26,192	47,434	44,170
Total assets at period end	5,890,442				5,182,879				5,890,442	5,182,879	4,617,858
Banking [Member]
Net interest income									121,583	114,983	110,001
Noninterest income									19,104	14,999	10,013
Total income									140,687	129,982	120,014
Provision for loan losses									32,400	4,000	3,550
Compensation and benefits									54,044	48,925	44,875
Premises and equipment expense									14,056	12,533	11,747
FDIC expense									1,975	277	2,443
Other noninterest expense									19,694	10,932	11,313
Total noninterest expense									122,169	76,667	73,928
Income before income tax expense									18,518	53,315	46,086
Income tax expense									2,170	15,069	10,819
Net income									16,348	38,246	35,267
Total assets at period end	5,798,770				5,095,744				5,798,770	5,095,744	4,547,179
Wealth Management [Member]
Net interest income									6,019	5,291	5,162
Noninterest income									42,656	39,697	34,180
Total income									48,675	44,988	39,342
Provision for loan losses									0	0	0
Compensation and benefits									23,472	21,204	17,927
Premises and equipment expense									2,321	2,202	1,750
FDIC expense									0	0	0
Other noninterest expense									9,397	8,775	8,031
Total noninterest expense									35,190	32,181	27,708
Income before income tax expense									13,485	12,807	11,634
Income tax expense									3,641	3,619	2,731
Net income									9,844	9,188	8,903
Total assets at period end	$ 91,672				$ 87,135				$ 91,672	$ 87,135	$ 70,679