MARKETABLE SECURITIES - Securities in Continuous Loss Position (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Gross Unrealized Losses
Less Than 12 Months	$ (33)	$ (638)
12 Months or Longer	(327)	(6,459)
Total	(360)	(7,097)
Estimated Fair Value
Less Than 12 Months	20,559	29,860
12 Months or Longer	44,710	191,232
Total	65,269	221,092
Gross Unrealized Losses
Less Than 12 Months	(1)	(561)
12 Months or Longer	(15)	(1,061)
Total	(16)	(1,622)
Estimated Fair Value
Less Than 12 Months	1,313	59,442
12 Months or Longer	7,791	38,828
Total	9,104	98,270
Corporate bonds
Gross Unrealized Losses
Less Than 12 Months	0	(453)
12 Months or Longer	0	(336)
Total	0	(789)
Estimated Fair Value
Less Than 12 Months	0	11,236
12 Months or Longer	0	7,718
Total	0	18,954
Mortgage-backed securities
Gross Unrealized Losses
Less Than 12 Months	(25)	(89)
12 Months or Longer	(310)	(3,587)
Total	(335)	(3,676)
Estimated Fair Value
Less Than 12 Months	19,421	7,173
12 Months or Longer	42,116	76,717
Total	61,537	83,890
Gross Unrealized Losses
Less Than 12 Months	0	(21)
12 Months or Longer	(13)	(479)
Total	(13)	(500)
Estimated Fair Value
Less Than 12 Months	0	1,478
12 Months or Longer	7,032	12,317
Total	7,032	13,795
Collateralized mortgage obligations
Gross Unrealized Losses
Less Than 12 Months	0	(79)
12 Months or Longer	(17)	(2,293)
Total	(17)	(2,372)
Estimated Fair Value
Less Than 12 Months	0	9,232
12 Months or Longer	2,594	99,390
Total	2,594	108,622
Gross Unrealized Losses
Less Than 12 Months	0	(28)
12 Months or Longer	0	0
Total	0	(28)
Estimated Fair Value
Less Than 12 Months	0	2,171
12 Months or Longer	0	0
Total	0	2,171
Municipal securities
Gross Unrealized Losses
Less Than 12 Months	(8)	(17)
12 Months or Longer	0	(243)
Total	(8)	(260)
Estimated Fair Value
Less Than 12 Months	1,138	2,219
12 Months or Longer	0	7,407
Total	1,138	9,626
Gross Unrealized Losses
Less Than 12 Months	(1)	(512)
12 Months or Longer	(2)	(582)
Total	(3)	(1,094)
Estimated Fair Value
Less Than 12 Months	1,313	55,793
12 Months or Longer	759	26,511
Total	$ 2,072	$ 82,304