SECURITIES (Securities with Continuous Loss Position) (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Schedule of Held-to-maturity Securities [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	$ 1,107,303	$ 189,078
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(24,306)	(1,135)
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	279,341	58,616
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(4,715)	(1,004)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	1,386,644	247,694
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss, Total	29,021	2,139
U.S. Government and agency obligations
Schedule of Held-to-maturity Securities [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	0	3,126
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0	(8)
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	70,401	50,603
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(784)	(927)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	70,401	53,729
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss, Total	784	935
Municipal bonds
Schedule of Held-to-maturity Securities [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	5,024	495
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(40)	(2)
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	2,716	0
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(7)	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	7,740	495
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss, Total	47	2
Corporate bonds
Schedule of Held-to-maturity Securities [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	0	3,586
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	0	(79)
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	2,986	0
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(14)	0
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	2,986	3,586
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss, Total	14	79
Mortgage-backed or related securities
Schedule of Held-to-maturity Securities [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	1,102,279	181,871
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	(24,266)	(1,046)
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	203,238	2,337
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	(3,910)	(14)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	1,305,517	184,208
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss, Total	$ 28,176	1,060
Asset-backed securities
Schedule of Held-to-maturity Securities [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value		0
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		0
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value		5,676
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		(63)
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value		5,676
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss, Total		$ 63