INVESTMENT SECURITIES - Schedule of Investment Securities' Gross Unrealized Losses and Fair Value by Investment Category (Details) - USD ($) $ in Thousands	Sep. 30, 2026	Dec. 31, 2025
Available-for-sale debt securities:
Available-for-sale debt securities, Less than 12 months, Fair value	$ 858,491	$ 80,612
Available-for-sale debt securities, Less than 12 months, Unrealized loss	40,459	504
Available-for-sale debt securities, 12 months or longer, Fair value	2,830,735	3,271,662
Available-for-sale debt securities, 12 months or longer, Unrealized loss	641,806	497,782
Available-for-sale debt securities, Total, Fair value	3,689,226	3,352,274
Available-for-sale debt securities, Total, Unrealized loss	682,265	498,286
CMO
Available-for-sale debt securities:
Available-for-sale debt securities, Less than 12 months, Fair value	47,071	0
Available-for-sale debt securities, Less than 12 months, Unrealized loss	1,243	0
Available-for-sale debt securities, 12 months or longer, Fair value	334,744	394,776
Available-for-sale debt securities, 12 months or longer, Unrealized loss	85,440	71,679
Available-for-sale debt securities, Total, Fair value	381,815	394,776
Available-for-sale debt securities, Total, Unrealized loss	86,683	71,679
FNMA MBS
Available-for-sale debt securities:
Available-for-sale debt securities, Less than 12 months, Fair value	713,650	68,311
Available-for-sale debt securities, Less than 12 months, Unrealized loss	34,376	353
Available-for-sale debt securities, 12 months or longer, Fair value	2,193,126	2,551,281
Available-for-sale debt securities, 12 months or longer, Unrealized loss	499,265	383,739
Available-for-sale debt securities, Total, Fair value	2,906,776	2,619,592
Available-for-sale debt securities, Total, Unrealized loss	533,641	384,092
FHLMC MBS
Available-for-sale debt securities:
Available-for-sale debt securities, Less than 12 months, Fair value	48,161	7,978
Available-for-sale debt securities, Less than 12 months, Unrealized loss	1,829	58
Available-for-sale debt securities, 12 months or longer, Fair value	93,361	103,510
Available-for-sale debt securities, 12 months or longer, Unrealized loss	12,199	7,484
Available-for-sale debt securities, Total, Fair value	141,522	111,488
Available-for-sale debt securities, Total, Unrealized loss	14,028	7,542
GNMA MBS
Available-for-sale debt securities:
Available-for-sale debt securities, Less than 12 months, Fair value	49,609	4,323
Available-for-sale debt securities, Less than 12 months, Unrealized loss	3,011	93
Available-for-sale debt securities, 12 months or longer, Fair value	31,522	34,290
Available-for-sale debt securities, 12 months or longer, Unrealized loss	4,514	2,387
Available-for-sale debt securities, Total, Fair value	81,131	38,613
Available-for-sale debt securities, Total, Unrealized loss	7,525	2,480
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	177,982	187,805
Available-for-sale debt securities, 12 months or longer, Unrealized loss	40,388	32,493
Available-for-sale debt securities, Total, Fair value	177,982	187,805
Available-for-sale debt securities, Total, Unrealized loss	$ 40,388	$ 32,493

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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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