BUSINESS SEGMENTS - Schedule of Income and Total Assets for Reportable Segments (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Net interest income	$ 30,007	$ 28,393
Noninterest income	11,729	10,215
Total income	41,736	38,608
Provision for loan and lease losses	100	1,250
Compensation and benefits	17,156	14,579
Premises and equipment expense	3,388	3,270
FDIC expense	277	580
Other noninterest expense	4,894	4,908
Total noninterest expense	25,815	24,587
Income before income tax expense	15,921	14,021
Income tax expense	4,496	3,214
NET INCOME	11,425	10,807
Total assets at period end	4,662,306	4,336,494	$ 4,617,858
Banking [Member]
Net interest income	28,566	26,848
Noninterest income	2,279	1,627
Total income	30,845	28,475
Provision for loan and lease losses	100	1,250
Compensation and benefits	11,997	10,331
Premises and equipment expense	2,925	2,839
FDIC expense	277	580
Other noninterest expense	2,758	2,807
Total noninterest expense	18,057	17,807
Income before income tax expense	12,788	10,668
Income tax expense	3,611	2,445
NET INCOME	9,177	8,223
Total assets at period end	4,582,200	4,278,010
Wealth Management Division [Member]
Net interest income	1,441	1,545
Noninterest income	9,450	8,588
Total income	10,891	10,133
Provision for loan and lease losses	0	0
Compensation and benefits	5,159	4,248
Premises and equipment expense	463	431
FDIC expense	0	0
Other noninterest expense	2,136	2,101
Total noninterest expense	7,758	6,780
Income before income tax expense	3,133	3,353
Income tax expense	885	769
NET INCOME	2,248	2,584
Total assets at period end	$ 80,106	$ 58,484