INVESTMENT SECURITIES - Schedule of Investment Securities' Gross Unrealized Losses and Fair Value by Investment Category (Details) - USD ($) $ in Thousands	Mar. 31, 2025	Dec. 31, 2024
Available-for-sale debt securities:
Available-for-sale debt securities, Less than 12 months, Fair value	$ 21,345	$ 51,381
Available-for-sale debt securities, Less than 12 months, Unrealized loss	243	668
Available-for-sale debt securities, 12 months or longer, Fair value	3,435,010	3,430,940
Available-for-sale debt securities, 12 months or longer, Unrealized loss	616,468	707,235
Available-for-sale debt securities, Total, Fair value	3,456,355	3,482,321
Available-for-sale debt securities, Total, Unrealized loss	616,711	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	418,473	420,663
Available-for-sale debt securities, 12 months or longer, Unrealized loss	86,970	95,967
Available-for-sale debt securities, Total, Fair value	418,473	420,663
Available-for-sale debt securities, Total, Unrealized loss	86,970	95,967
FNMA MBS
Available-for-sale debt securities:
Available-for-sale debt securities, Less than 12 months, Fair value	19,727	46,971
Available-for-sale debt securities, Less than 12 months, Unrealized loss	237	525
Available-for-sale debt securities, 12 months or longer, Fair value	2,690,619	2,691,778
Available-for-sale debt securities, 12 months or longer, Unrealized loss	476,743	549,486
Available-for-sale debt securities, Total, Fair value	2,710,346	2,738,749
Available-for-sale debt securities, Total, Unrealized loss	476,980	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	106,004	105,508
Available-for-sale debt securities, 12 months or longer, Unrealized loss	10,793	13,091
Available-for-sale debt securities, Total, Fair value	106,004	105,514
Available-for-sale debt securities, Total, Unrealized loss	10,793	13,091
GNMA MBS
Available-for-sale debt securities:
Available-for-sale debt securities, Less than 12 months, Fair value	1,618	4,404
Available-for-sale debt securities, Less than 12 months, Unrealized loss	6	143
Available-for-sale debt securities, 12 months or longer, Fair value	36,518	35,054
Available-for-sale debt securities, 12 months or longer, Unrealized loss	3,132	3,759
Available-for-sale debt securities, Total, Fair value	38,136	39,458
Available-for-sale debt securities, Total, Unrealized loss	3,138	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	183,396	177,937
Available-for-sale debt securities, 12 months or longer, Unrealized loss	38,830	44,932
Available-for-sale debt securities, Total, Fair value	183,396	177,937
Available-for-sale debt securities, Total, Unrealized loss	$ 38,830	$ 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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