INVESTMENT SECURITIES (HTM Debt Securities) (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	$ 5,229,562	$ 3,938,797
Gross Unrealized Gains	186,088	31,469
Gross Unrealized Loss	(930)	(13,039)
Fair Value	5,414,720	3,957,227
ABS
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	23,342	0
Gross Unrealized Gains	353	0
Gross Unrealized Loss	0	0
Fair Value	23,695	0
GNMA - Residential
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	2,319,089	1,948,025
Gross Unrealized Gains	62,751	11,354
Gross Unrealized Loss	(930)	(7,670)
Fair Value	2,380,910	1,951,709
GNMA - Commercial
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	2,887,131	1,990,772
Gross Unrealized Gains	122,984	20,115
Gross Unrealized Loss	0	(5,369)
Fair Value	$ 3,010,115	$ 2,005,518