Quarterly report [Sections 13 or 15(d)]

SECURITIES AND OTHER INVESTMENTS (Amortized Cost, Gross Unrealized Gains and Losses, and Estimated Fair Values of Investment Securities) (Details)

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SECURITIES AND OTHER INVESTMENTS (Amortized Cost, Gross Unrealized Gains and Losses, and Estimated Fair Values of Investment Securities) (Details) - USD ($)
$ in Thousands
Sep. 30, 2025
Dec. 31, 2024
Debt Securities, Available-for-sale Securities, Amortized Cost Basis [Abstract]    
Total AFS securities $ 4,595,098 $ 2,844,763
Gross Unrealized Gains 16,587 3,378
Gross Unrealized (Losses) (344,162) (405,975)
Total AFS securities, Estimated Fair Value 4,267,523 2,442,166
US Government Agencies Debt Securities [Member]    
Debt Securities, Available-for-sale Securities, Amortized Cost Basis [Abstract]    
Total AFS securities 128,592 65,650
Gross Unrealized Gains 723 390
Gross Unrealized (Losses) (34) (27)
Total AFS securities, Estimated Fair Value 129,281 66,013
US States and Political Subdivisions Debt Securities [Member]    
Debt Securities, Available-for-sale Securities, Amortized Cost Basis [Abstract]    
Total AFS securities 598,767 597,956
Gross Unrealized Gains 186 84
Gross Unrealized (Losses) (117,438) (129,703)
Total AFS securities, Estimated Fair Value 481,515 468,337
Corporate Bond Securities [Member]    
Debt Securities, Available-for-sale Securities, Amortized Cost Basis [Abstract]    
Total AFS securities 250,663 253,526
Gross Unrealized Gains 686 505
Gross Unrealized (Losses) (5,194) (9,319)
Total AFS securities, Estimated Fair Value 246,155 244,712
Commercial Mortgage-Backed Securities [Member]    
Debt Securities, Available-for-sale Securities, Amortized Cost Basis [Abstract]    
Total AFS securities 462,479 347,501
Gross Unrealized Gains 1,370 352
Gross Unrealized (Losses) (42,929) (46,788)
Total AFS securities, Estimated Fair Value 420,920 301,065
Commercial Mortgage-Backed Securities [Member] | Agency Securities [Member]    
Debt Securities, Available-for-sale Securities, Amortized Cost Basis [Abstract]    
Total AFS securities 359,154 285,949
Gross Unrealized Gains 1,148 348
Gross Unrealized (Losses) (40,826) (44,678)
Total AFS securities, Estimated Fair Value 319,476 241,619
Commercial Mortgage-Backed Securities [Member] | Non-agency    
Debt Securities, Available-for-sale Securities, Amortized Cost Basis [Abstract]    
Total AFS securities 103,325 61,552
Gross Unrealized Gains 222 4
Gross Unrealized (Losses) (2,103) (2,110)
Total AFS securities, Estimated Fair Value 101,444 59,446
Residential Mortgage-Backed Securities [Member]    
Debt Securities, Available-for-sale Securities, Amortized Cost Basis [Abstract]    
Total AFS securities 3,152,665 1,578,270
Gross Unrealized Gains 13,622 2,047
Gross Unrealized (Losses) (178,567) (220,138)
Total AFS securities, Estimated Fair Value 2,987,720 1,360,179
Residential Mortgage-Backed Securities [Member] | Agency Securities [Member]    
Debt Securities, Available-for-sale Securities, Amortized Cost Basis [Abstract]    
Total AFS securities 2,968,326 1,478,648
Gross Unrealized Gains 12,772 1,375
Gross Unrealized (Losses) (175,713) (216,754)
Total AFS securities, Estimated Fair Value 2,805,385 1,263,269
Residential Mortgage-Backed Securities [Member] | Non-agency    
Debt Securities, Available-for-sale Securities, Amortized Cost Basis [Abstract]    
Total AFS securities 184,339 99,622
Gross Unrealized Gains 850 672
Gross Unrealized (Losses) (2,854) (3,384)
Total AFS securities, Estimated Fair Value 182,335 96,910
Collateralized Securities, Other [Member]    
Debt Securities, Available-for-sale Securities, Amortized Cost Basis [Abstract]    
Total AFS securities 1,932 1,860
Gross Unrealized Gains 0 0
Gross Unrealized (Losses) 0 0
Total AFS securities, Estimated Fair Value $ 1,932 $ 1,860