SECURITIES (Schedule of Carrying Value, Gross Unrealized Gains and Losses and Estimated Fair Value of Securities) (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Schedule of Held-to-maturity Securities [Line Items]
Total HTM Securities	$ 535,722	$ 544,851
Gross Unrealized Gains	62,768	74,982
Gross Unrealized Losses	(38)	(68)
Held-to-maturity Securities, Fair Value	598,452	619,765
U.S. government and agency securities
Schedule of Held-to-maturity Securities [Line Items]
Total HTM Securities	2,637	2,751
Gross Unrealized Gains	2	0
Gross Unrealized Losses	(8)	(18)
Held-to-maturity Securities, Fair Value	2,631	2,733
Obligations of states and political subdivisions
Schedule of Held-to-maturity Securities [Line Items]
Total HTM Securities	528,157	536,767
Gross Unrealized Gains	62,763	74,978
Gross Unrealized Losses	0	0
Held-to-maturity Securities, Fair Value	590,920	611,745
Commercial
Schedule of Held-to-maturity Securities [Line Items]
Total HTM Securities	4,928	5,333
Gross Unrealized Gains	3	4
Gross Unrealized Losses	(30)	(50)
Held-to-maturity Securities, Fair Value	4,901	5,287
Agency | Commercial
Schedule of Held-to-maturity Securities [Line Items]
Total HTM Securities	4,928	5,333
Gross Unrealized Gains	3	4
Gross Unrealized Losses	(30)	(50)
Held-to-maturity Securities, Fair Value	4,901	5,287
Non-agency | Commercial
Schedule of Held-to-maturity Securities [Line Items]
Total HTM Securities	0	0
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Held-to-maturity Securities, Fair Value	$ 0	$ 0