SECURITIES - Realized Gain (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2020	Dec. 31, 2019
Investments, Debt and Equity Securities [Abstract]
Gross Realized Gains	$ 539,255	$ 2,526
Gross Realized Losses	(271,998)	(95,040)
Net Realized Gains (Losses)	$ 267,257	$ (92,514)