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
Jun. 30, 2026
Dec. 31, 2025
Debt Securities, Available-for-sale Securities, Amortized Cost Basis [Abstract]    
Total AFS securities $ 4,193,823 $ 4,489,998
Gross Unrealized Gains 6,737 19,804
Gross Unrealized (Losses) (323,843) (315,501)
Total AFS securities, Estimated Fair Value 3,876,717 4,194,301
US Government Agencies Debt Securities [Member]    
Debt Securities, Available-for-sale Securities, Amortized Cost Basis [Abstract]    
Total AFS securities 101,072 103,335
Gross Unrealized Gains 192 681
Gross Unrealized (Losses) (152) (14)
Total AFS securities, Estimated Fair Value 101,112 104,002
US States and Political Subdivisions Debt Securities [Member]    
Debt Securities, Available-for-sale Securities, Amortized Cost Basis [Abstract]    
Total AFS securities 591,738 589,194
Gross Unrealized Gains 88 178
Gross Unrealized (Losses) (100,555) (101,487)
Total AFS securities, Estimated Fair Value 491,271 487,885
Corporate Bond Securities [Member]    
Debt Securities, Available-for-sale Securities, Amortized Cost Basis [Abstract]    
Total AFS securities 196,797 221,432
Gross Unrealized Gains 537 709
Gross Unrealized (Losses) (2,750) (4,207)
Total AFS securities, Estimated Fair Value 194,584 217,934
Commercial Mortgage-Backed Securities [Member]    
Debt Securities, Available-for-sale Securities, Amortized Cost Basis [Abstract]    
Total AFS securities 463,080 469,414
Gross Unrealized Gains 587 1,463
Gross Unrealized (Losses) (43,261) (41,711)
Total AFS securities, Estimated Fair Value 420,406 429,166
Commercial Mortgage-Backed Securities [Member] | Agency Securities [Member]    
Debt Securities, Available-for-sale Securities, Amortized Cost Basis [Abstract]    
Total AFS securities 334,878 354,405
Gross Unrealized Gains 508 1,276
Gross Unrealized (Losses) (40,131) (39,806)
Total AFS securities, Estimated Fair Value 295,255 315,875
Commercial Mortgage-Backed Securities [Member] | Non-agency    
Debt Securities, Available-for-sale Securities, Amortized Cost Basis [Abstract]    
Total AFS securities 128,202 115,009
Gross Unrealized Gains 79 187
Gross Unrealized (Losses) (3,130) (1,905)
Total AFS securities, Estimated Fair Value 125,151 113,291
Residential Mortgage-Backed Securities [Member]    
Debt Securities, Available-for-sale Securities, Amortized Cost Basis [Abstract]    
Total AFS securities 2,839,136 3,104,667
Gross Unrealized Gains 5,333 16,773
Gross Unrealized (Losses) (177,125) (168,082)
Total AFS securities, Estimated Fair Value 2,667,344 2,953,358
Residential Mortgage-Backed Securities [Member] | Agency Securities [Member]    
Debt Securities, Available-for-sale Securities, Amortized Cost Basis [Abstract]    
Total AFS securities 2,711,777 2,942,900
Gross Unrealized Gains 4,651 15,838
Gross Unrealized (Losses) (174,198) (165,524)
Total AFS securities, Estimated Fair Value 2,542,230 2,793,214
Residential Mortgage-Backed Securities [Member] | Non-agency    
Debt Securities, Available-for-sale Securities, Amortized Cost Basis [Abstract]    
Total AFS securities 127,359 161,767
Gross Unrealized Gains 682 935
Gross Unrealized (Losses) (2,927) (2,558)
Total AFS securities, Estimated Fair Value 125,114 160,144
Collateralized Securities, Other [Member]    
Debt Securities, Available-for-sale Securities, Amortized Cost Basis [Abstract]    
Total AFS securities 2,000 1,956
Gross Unrealized Gains 0 0
Gross Unrealized (Losses) 0 0
Total AFS securities, Estimated Fair Value $ 2,000 $ 1,956