MARKETABLE SECURITIES - Securities in Continuous Loss Position (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Gross Unrealized Losses
Less Than 12 Months	$ (821)	$ (95)
12 Months or Longer	0	(1)
Total	(821)	(96)
Estimated Fair Value
Less Than 12 Months	70,276	28,268
12 Months or Longer	0	106
Total	70,276	28,374
Corporate bonds
Gross Unrealized Losses
Less Than 12 Months	(77)	(8)
12 Months or Longer	0
Total	(77)	(8)
Estimated Fair Value
Less Than 12 Months	6,423	2,493
12 Months or Longer	0
Total	6,423	2,493
Mortgage-backed securities
Gross Unrealized Losses
Less Than 12 Months	(609)	(87)
12 Months or Longer	0
Total	(609)	(87)
Estimated Fair Value
Less Than 12 Months	50,451	25,775
12 Months or Longer	0
Total	50,451	25,775
Collateralized mortgage obligations
Gross Unrealized Losses
Less Than 12 Months	(19)
12 Months or Longer	0	(1)
Total	(19)	(1)
Estimated Fair Value
Less Than 12 Months	8,993
12 Months or Longer	0	106
Total	8,993	$ 106
Municipal securities
Gross Unrealized Losses
Less Than 12 Months	(116)
12 Months or Longer	0
Total	(116)
Estimated Fair Value
Less Than 12 Months	4,409
12 Months or Longer	0
Total	$ 4,409