REVENUE FROM CONTRACTS WITH CUSTOMERS - Schedule of Disaggregation of Revenue (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Disaggregation of Revenue [Line Items]
Service charges on deposit accounts	$ 44,145	$ 50,792	$ 46,128
Other service charges, commissions and fees	3,914	3,566	2,971
Other noninterest income	17,133	18,150	12,968
Service charges on deposit accounts
Disaggregation of Revenue [Line Items]
ASC 606 revenue items	44,145	50,792	46,128
Debit card interchange fees
Disaggregation of Revenue [Line Items]
ASC 606 revenue items	15,988	18,909	18,945
Overdraft fees
Disaggregation of Revenue [Line Items]
ASC 606 revenue items	17,903	21,710	18,267
Other service charges on deposit accounts
Disaggregation of Revenue [Line Items]
ASC 606 revenue items	10,254	10,173	8,916
Other service charges, commissions and fees
Disaggregation of Revenue [Line Items]
ASC 606 revenue items	3,633	3,228	2,721
Other	281	338	250
ATM fees
Disaggregation of Revenue [Line Items]
ASC 606 revenue items	3,633	3,228	2,721
Other noninterest income
Disaggregation of Revenue [Line Items]
ASC 606 revenue items	3,142	1,467	89
Other	13,991	16,683	12,879
Trust and wealth management
Disaggregation of Revenue [Line Items]
ASC 606 revenue items	$ 3,142	$ 1,467	$ 89