INVESTMENTS (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Debt Securities, Trading, Gain (Loss) [Abstract]
Cost	$ 37,149		$ 50,065
Gross Unrealized Gains	331		259
Gross Unrealized Losses	(208)		0
Debt Securities, Trading	37,272		50,324
Equity Securities, FV-NI, Gain (Loss) [Abstract]
Cost	40,819		53,735
Gross Unrealized Gains	344		827
Gross Unrealized Losses	(648)		0
Estimated Fair Value	40,515		54,562
Unrealized gains (losses) on private investments	(995)	$ 0	2,800
Unrealized Gain on Securities	1,000		600
U.S. Government and Government agency obligations
Debt Securities, Trading, Gain (Loss) [Abstract]
Cost	27,418		39,074
Gross Unrealized Gains	331		174
Gross Unrealized Losses	0		0
Debt Securities, Trading	27,749		39,248
Money market funds
Debt Securities, Trading, Gain (Loss) [Abstract]
Cost	5,065		4,592
Gross Unrealized Gains	0		0
Gross Unrealized Losses	0		0
Debt Securities, Trading	5,065		4,592
Equity funds
Debt Securities, Trading, Gain (Loss) [Abstract]
Cost	4,666		6,399
Gross Unrealized Gains	0		85
Gross Unrealized Losses	(208)		0
Debt Securities, Trading	4,458		6,484
Private investment fund
Equity Securities, FV-NI, Gain (Loss) [Abstract]
Cost	250		250
Gross Unrealized Gains	13		13
Gross Unrealized Losses	0		0
Estimated Fair Value	263		263
Private equity
Equity Securities, FV-NI, Gain (Loss) [Abstract]
Cost	3,420		3,420
Gross Unrealized Gains	0		555
Gross Unrealized Losses	(440)		0
Estimated Fair Value	$ 2,980		$ 3,975