MARKETABLE SECURITIES - Sale of Securities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Sale of Marketable Securities [Abstract]
Proceeds from sales	$ 3,957	$ 411,796	$ 217,111
Gross gains	0	4	180
Gross losses	(22)	(54)	(13)
Debt Securities, Held-to-maturity, Sale, Excluding Other-than-temporary Impairment [Abstract]
Proceeds from sales	0	0	3,298
Amortized cost	0	0	3,140
Gross realized gains	0	0	158
Tax expense related to securities gains/losses	$ 0	$ 0	$ (44)