INVESTMENT SECURITIES (Gains (Losses) and Proceeds on Sale of Investment Securities) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Investments, Debt and Equity Securities [Abstract]
Proceeds from the sales of AFS securities	$ 631,459	$ 344,792	$ 1,553,560	$ 627,664
Gross realized gains	22,516	2,528	32,829	3,340
Gross realized losses	0	(149)	(1,034)	(2,961)
Net realized gains/(losses)	22,516	2,379	31,795	379
Net realized gains/(losses) on trading securities	$ 500	$ (12)	$ (900)	$ (300)