INCOME TAXES (Effective Income Tax Rate Reconciliation) (Details)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Document Period End Date	Dec. 31, 2019
Effective Income Tax Rate, Continuing Operations, Tax Rate Reconciliation [Abstract]
Federal income tax statutory rate	21.00%	21.00%	35.00%
Increase (decrease) in tax rate due to:
Tax-exempt interest	(2.20%)	(2.00%)	(2.60%)
Investment in life insurance	(0.50%)	(0.60%)	(1.10%)
State income taxes, net of federal tax offset	2.00%	2.30%	2.00%
Tax credits	(1.20%)	(0.80%)	(0.60%)
Change in effective income tax rate due to merger and acquisition costs	0.10%	0.10%	0.00%
Merger and acquisition costs	0.00%	(2.50%)	0.00%
Increase in federal statutory income tax rate due to 2017 Tax Cuts and Jobs Act	0.00%	0.00%	28.20%
Effective Income Tax Rate Reconciliation, State Audits And Amended Returns, Percent	(0.50%)	0.00%	0.00%
Other	1.40%	(0.20%)	(1.10%)
Effective income tax rate	20.10%	17.30%	59.80%