INVESTMENTS (Schedule of Unrealized Gross Losses and Estimated Fair values of Investment Securities) (Details) $ in Thousands	Mar. 31, 2022 USD ($) security	Dec. 31, 2021 USD ($) security
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions | security	359	180
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	$ 1,084,105	$ 871,583
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	72,416	14,074
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	207,859	101,074
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(23,054)	(3,656)
Debt Securities, Available-for-sale, Unrealized Loss Position, Total	1,291,964	972,657
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	$ 95,470	$ 17,730
Obligations of states and political subdivisions
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions | security	30	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	$ 46,149	$ 0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	2,019	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	0	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0	0
Debt Securities, Available-for-sale, Unrealized Loss Position, Total	46,149	0
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	$ 2,019	$ 0
Mortgage-backed securities issued or guaranteed by U.S. government-sponsored enterprises
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions | security	215	113
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	$ 819,454	$ 659,851
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	58,095	8,999
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	99,504	61,978
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(10,956)	(2,469)
Debt Securities, Available-for-sale, Unrealized Loss Position, Total	918,958	721,829
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	$ 69,051	$ 11,468
Collateralized mortgage obligations issued or guaranteed by U.S. government-sponsored enterprises
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions | security	98	56
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	$ 196,036	$ 191,456
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	10,751	4,602
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	102,752	38,117
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(11,501)	(1,165)
Debt Securities, Available-for-sale, Unrealized Loss Position, Total	298,788	229,573
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	$ 22,252	$ 5,767
Subordinated corporate bonds
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions | security	12	7
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	$ 19,433	$ 11,932
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	1,199	232
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	966	979
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(34)	(22)
Debt Securities, Available-for-sale, Unrealized Loss Position, Total	20,399	12,911
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	$ 1,233	$ 254
Obligations of U.S. government-sponsored enterprises
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Unrealized Loss Position, Number of Positions | security	4	4
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	$ 3,033	$ 8,344
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	352	241
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	4,637	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(563)	0
Debt Securities, Available-for-sale, Unrealized Loss Position, Total	7,670	8,344
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	$ 915	$ 241