SECURITIES (Schedule of Carrying Value, Gross Unrealized Gains and Losses and Estimated Fair Value of Securities) (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Schedule of Held-to-maturity Securities [Line Items]
Total HTM Securities	$ 544,851	$ 555,144
Gross Unrealized Gains	74,982	48,359
Gross Unrealized Losses	(68)	0
Held-to-maturity Securities, Fair Value	619,765	603,503
U.S. government and agency securities
Schedule of Held-to-maturity Securities [Line Items]
Total HTM Securities	2,751	2,813
Gross Unrealized Gains	0	26
Gross Unrealized Losses	(18)	0
Held-to-maturity Securities, Fair Value	2,733	2,839
Obligations of states and political subdivisions
Schedule of Held-to-maturity Securities [Line Items]
Total HTM Securities	536,767	545,148
Gross Unrealized Gains	74,978	48,274
Gross Unrealized Losses	0	0
Held-to-maturity Securities, Fair Value	611,745	593,422
Commercial
Schedule of Held-to-maturity Securities [Line Items]
Total HTM Securities	5,333	7,183
Gross Unrealized Gains	4	59
Gross Unrealized Losses	(50)	0
Held-to-maturity Securities, Fair Value	5,287	7,242
Agency | Commercial
Schedule of Held-to-maturity Securities [Line Items]
Total HTM Securities	5,333	7,183
Gross Unrealized Gains	4	59
Gross Unrealized Losses	(50)	0
Held-to-maturity Securities, Fair Value	5,287	7,242
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