SECURITIES (Schedule of Carrying Value, Gross Unrealized Gains and Losses and Estimated Fair Value of Securities) (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Schedule of Held-to-maturity Securities [Line Items]
Total HTM Securities	$ 546,661	$ 555,144
Gross Unrealized Gains	67,566	48,359
Gross Unrealized Losses	(54)	0
Held-to-maturity Securities, Fair Value	614,173	603,503
U.S. government and agency securities
Schedule of Held-to-maturity Securities [Line Items]
Total HTM Securities	2,767	2,813
Gross Unrealized Gains	0	26
Gross Unrealized Losses	(14)	0
Held-to-maturity Securities, Fair Value	2,753	2,839
Obligations of states and political subdivisions
Schedule of Held-to-maturity Securities [Line Items]
Total HTM Securities	538,352	545,148
Gross Unrealized Gains	67,561	48,274
Gross Unrealized Losses	0	0
Held-to-maturity Securities, Fair Value	605,913	593,422
Commercial
Schedule of Held-to-maturity Securities [Line Items]
Total HTM Securities	5,542	7,183
Gross Unrealized Gains	5	59
Gross Unrealized Losses	(40)	0
Held-to-maturity Securities, Fair Value	5,507	7,242
Agency | Commercial
Schedule of Held-to-maturity Securities [Line Items]
Total HTM Securities	5,542	7,183
Gross Unrealized Gains	5	59
Gross Unrealized Losses	(40)	0
Held-to-maturity Securities, Fair Value	5,507	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