INVESTMENT SECURITIES - Schedule of Investment Securities' Gross Unrealized Losses and Fair Value by Investment Category (Details) - USD ($) $ in Thousands	Jun. 30, 2025	Dec. 31, 2024
Available-for-sale debt securities:
Available-for-sale debt securities, Less than 12 months, Fair value	$ 27,838	$ 51,381
Available-for-sale debt securities, Less than 12 months, Unrealized loss	227	668
Available-for-sale debt securities, 12 months or longer, Fair value	3,364,817	3,430,940
Available-for-sale debt securities, 12 months or longer, Unrealized loss	587,022	707,235
Available-for-sale debt securities, Total, Fair value	3,392,655	3,482,321
Available-for-sale debt securities, Total, Unrealized loss	587,249	707,903
CMO
Available-for-sale debt securities:
Available-for-sale debt securities, Less than 12 months, Fair value	0	0
Available-for-sale debt securities, Less than 12 months, Unrealized loss	0	0
Available-for-sale debt securities, 12 months or longer, Fair value	411,404	420,663
Available-for-sale debt securities, 12 months or longer, Unrealized loss	82,533	95,967
Available-for-sale debt securities, Total, Fair value	411,404	420,663
Available-for-sale debt securities, Total, Unrealized loss	82,533	95,967
FNMA MBS
Available-for-sale debt securities:
Available-for-sale debt securities, Less than 12 months, Fair value	26,386	46,971
Available-for-sale debt securities, Less than 12 months, Unrealized loss	222	525
Available-for-sale debt securities, 12 months or longer, Fair value	2,628,263	2,691,778
Available-for-sale debt securities, 12 months or longer, Unrealized loss	454,503	549,486
Available-for-sale debt securities, Total, Fair value	2,654,649	2,738,749
Available-for-sale debt securities, Total, Unrealized loss	454,725	550,011
FHLMC MBS
Available-for-sale debt securities:
Available-for-sale debt securities, Less than 12 months, Fair value	0	6
Available-for-sale debt securities, Less than 12 months, Unrealized loss	0	0
Available-for-sale debt securities, 12 months or longer, Fair value	105,150	105,508
Available-for-sale debt securities, 12 months or longer, Unrealized loss	9,762	13,091
Available-for-sale debt securities, Total, Fair value	105,150	105,514
Available-for-sale debt securities, Total, Unrealized loss	9,762	13,091
GNMA MBS
Available-for-sale debt securities:
Available-for-sale debt securities, Less than 12 months, Fair value	1,452	4,404
Available-for-sale debt securities, Less than 12 months, Unrealized loss	5	143
Available-for-sale debt securities, 12 months or longer, Fair value	35,697	35,054
Available-for-sale debt securities, 12 months or longer, Unrealized loss	2,949	3,759
Available-for-sale debt securities, Total, Fair value	37,149	39,458
Available-for-sale debt securities, Total, Unrealized loss	2,954	3,902
GSE agency notes
Available-for-sale debt securities:
Available-for-sale debt securities, Less than 12 months, Fair value	0	0
Available-for-sale debt securities, Less than 12 months, Unrealized loss	0	0
Available-for-sale debt securities, 12 months or longer, Fair value	184,303	177,937
Available-for-sale debt securities, 12 months or longer, Unrealized loss	37,275	44,932
Available-for-sale debt securities, Total, Fair value	184,303	177,937
Available-for-sale debt securities, Total, Unrealized loss	$ 37,275	$ 44,932

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for more than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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