INVESTMENT SECURITIES - Schedule of Investment Securities' Gross Unrealized Losses and Fair Value by Investment Category (Details) - USD ($) $ in Thousands	Jun. 30, 2026	Dec. 31, 2025
Available-for-sale debt securities:
Available-for-sale debt securities, Less than 12 months, Fair value	$ 525,681	$ 80,612
Available-for-sale debt securities, Less than 12 months, Unrealized loss	6,834	504
Available-for-sale debt securities, 12 months or longer, Fair value	3,063,307	3,271,662
Available-for-sale debt securities, 12 months or longer, Unrealized loss	513,275	497,782
Available-for-sale debt securities, Total, Fair value	3,588,988	3,352,274
Available-for-sale debt securities, Total, Unrealized loss	520,109	498,286
CMO
Available-for-sale debt securities:
Available-for-sale debt securities, Less than 12 months, Fair value	13,431	0
Available-for-sale debt securities, Less than 12 months, Unrealized loss	256	0
Available-for-sale debt securities, 12 months or longer, Fair value	358,632	394,776
Available-for-sale debt securities, 12 months or longer, Unrealized loss	73,191	71,679
Available-for-sale debt securities, Total, Fair value	372,063	394,776
Available-for-sale debt securities, Total, Unrealized loss	73,447	71,679
FNMA MBS
Available-for-sale debt securities:
Available-for-sale debt securities, Less than 12 months, Fair value	457,986	68,311
Available-for-sale debt securities, Less than 12 months, Unrealized loss	6,020	353
Available-for-sale debt securities, 12 months or longer, Fair value	2,390,367	2,551,281
Available-for-sale debt securities, 12 months or longer, Unrealized loss	395,318	383,739
Available-for-sale debt securities, Total, Fair value	2,848,353	2,619,592
Available-for-sale debt securities, Total, Unrealized loss	401,338	384,092
FHLMC MBS
Available-for-sale debt securities:
Available-for-sale debt securities, Less than 12 months, Fair value	34,840	7,978
Available-for-sale debt securities, Less than 12 months, Unrealized loss	287	58
Available-for-sale debt securities, 12 months or longer, Fair value	99,009	103,510
Available-for-sale debt securities, 12 months or longer, Unrealized loss	8,396	7,484
Available-for-sale debt securities, Total, Fair value	133,849	111,488
Available-for-sale debt securities, Total, Unrealized loss	8,683	7,542
GNMA MBS
Available-for-sale debt securities:
Available-for-sale debt securities, Less than 12 months, Fair value	19,424	4,323
Available-for-sale debt securities, Less than 12 months, Unrealized loss	271	93
Available-for-sale debt securities, 12 months or longer, Fair value	30,010	34,290
Available-for-sale debt securities, 12 months or longer, Unrealized loss	2,646	2,387
Available-for-sale debt securities, Total, Fair value	49,434	38,613
Available-for-sale debt securities, Total, Unrealized loss	2,917	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	185,289	187,805
Available-for-sale debt securities, 12 months or longer, Unrealized loss	33,724	32,493
Available-for-sale debt securities, Total, Fair value	185,289	187,805
Available-for-sale debt securities, Total, Unrealized loss	$ 33,724	$ 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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