INVESTMENT SECURITIES - Debt Securities, Held-to-Maturity, Credit Quality Indicator (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 31, 2023
Schedule of Held-to-Maturity Securities [Line Items]
Investment securities held to maturity	$ 962,799	$ 1,103,170
Asset-backed securities
Schedule of Held-to-Maturity Securities [Line Items]
Investment securities held to maturity	446,070	575,990
Agency-guaranteed residential mortgage-backed securities
Schedule of Held-to-Maturity Securities [Line Items]
Investment securities held to maturity	6,960	7,039
Agency-guaranteed commercial mortgage-backed securities
Schedule of Held-to-Maturity Securities [Line Items]
Investment securities held to maturity	1,810	1,850
Agency-guaranteed residential collateralized mortgage obligations
Schedule of Held-to-Maturity Securities [Line Items]
Investment securities held to maturity	178,761	186,636
Agency-guaranteed commercial collateralized mortgage obligations
Schedule of Held-to-Maturity Securities [Line Items]
Investment securities held to maturity	145,173	146,765
Private label collateralized mortgage obligations
Schedule of Held-to-Maturity Securities [Line Items]
Investment securities held to maturity	184,025	$ 184,890
AAA
Schedule of Held-to-Maturity Securities [Line Items]
Investment securities held to maturity	83,903
AAA \| Asset-backed securities
Schedule of Held-to-Maturity Securities [Line Items]
Investment securities held to maturity	0
AAA \| Agency-guaranteed residential mortgage-backed securities
Schedule of Held-to-Maturity Securities [Line Items]
Investment securities held to maturity	0
AAA \| Agency-guaranteed commercial mortgage-backed securities
Schedule of Held-to-Maturity Securities [Line Items]
Investment securities held to maturity	0
AAA \| Agency-guaranteed residential collateralized mortgage obligations
Schedule of Held-to-Maturity Securities [Line Items]
Investment securities held to maturity	0
AAA \| Agency-guaranteed commercial collateralized mortgage obligations
Schedule of Held-to-Maturity Securities [Line Items]
Investment securities held to maturity	0
AAA \| Private label collateralized mortgage obligations
Schedule of Held-to-Maturity Securities [Line Items]
Investment securities held to maturity	83,903
AA
Schedule of Held-to-Maturity Securities [Line Items]
Investment securities held to maturity	26,124
AA \| Asset-backed securities
Schedule of Held-to-Maturity Securities [Line Items]
Investment securities held to maturity	0
AA \| Agency-guaranteed residential mortgage-backed securities
Schedule of Held-to-Maturity Securities [Line Items]
Investment securities held to maturity	0
AA \| Agency-guaranteed commercial mortgage-backed securities
Schedule of Held-to-Maturity Securities [Line Items]
Investment securities held to maturity	0
AA \| Agency-guaranteed residential collateralized mortgage obligations
Schedule of Held-to-Maturity Securities [Line Items]
Investment securities held to maturity	0
AA \| Agency-guaranteed commercial collateralized mortgage obligations
Schedule of Held-to-Maturity Securities [Line Items]
Investment securities held to maturity	0
AA \| Private label collateralized mortgage obligations
Schedule of Held-to-Maturity Securities [Line Items]
Investment securities held to maturity	26,124
Not Rated
Schedule of Held-to-Maturity Securities [Line Items]
Investment securities held to maturity	852,772
Not Rated \| Asset-backed securities
Schedule of Held-to-Maturity Securities [Line Items]
Investment securities held to maturity	446,070
Not Rated \| Agency-guaranteed residential mortgage-backed securities
Schedule of Held-to-Maturity Securities [Line Items]
Investment securities held to maturity	6,960
Not Rated \| Agency-guaranteed commercial mortgage-backed securities
Schedule of Held-to-Maturity Securities [Line Items]
Investment securities held to maturity	1,810
Not Rated \| Agency-guaranteed residential collateralized mortgage obligations
Schedule of Held-to-Maturity Securities [Line Items]
Investment securities held to maturity	178,761
Not Rated \| Agency-guaranteed commercial collateralized mortgage obligations
Schedule of Held-to-Maturity Securities [Line Items]
Investment securities held to maturity	145,173
Not Rated \| Private label collateralized mortgage obligations
Schedule of Held-to-Maturity Securities [Line Items]
Investment securities held to maturity	$ 73,998