SECURITIES AND OTHER INVESTMENTS (Amortized Cost, Gross Unrealized Gains and Losses, and Estimated Fair Values of Investment Securities) (Details) - USD ($) $ in Thousands	Mar. 31, 2025	Dec. 31, 2024
Debt Securities, Available-for-sale Securities, Amortized Cost Basis [Abstract]
Total AFS securities	$ 2,865,872	$ 2,844,763
Gross Unrealized Gains	5,508	3,378
Gross Unrealized (Losses)	(387,545)	(405,975)
Total AFS securities, Estimated Fair Value	2,483,835	2,442,166
US Government Agencies Debt Securities [Member]
Debt Securities, Available-for-sale Securities, Amortized Cost Basis [Abstract]
Total AFS securities	65,428	65,650
Gross Unrealized Gains	680	390
Gross Unrealized (Losses)	(13)	(27)
Total AFS securities, Estimated Fair Value	66,095	66,013
US States and Political Subdivisions Debt Securities [Member]
Debt Securities, Available-for-sale Securities, Amortized Cost Basis [Abstract]
Total AFS securities	593,973	597,956
Gross Unrealized Gains	125	84
Gross Unrealized (Losses)	(137,728)	(129,703)
Total AFS securities, Estimated Fair Value	456,370	468,337
Corporate Bond Securities [Member]
Debt Securities, Available-for-sale Securities, Amortized Cost Basis [Abstract]
Total AFS securities	245,806	253,526
Gross Unrealized Gains	558	505
Gross Unrealized (Losses)	(7,534)	(9,319)
Total AFS securities, Estimated Fair Value	238,830	244,712
Commercial Mortgage-Backed Securities [Member]
Debt Securities, Available-for-sale Securities, Amortized Cost Basis [Abstract]
Total AFS securities	356,209	347,501
Gross Unrealized Gains	758	352
Gross Unrealized (Losses)	(43,533)	(46,788)
Total AFS securities, Estimated Fair Value	313,434	301,065
Commercial Mortgage-Backed Securities [Member] | Agency Securities [Member]
Debt Securities, Available-for-sale Securities, Amortized Cost Basis [Abstract]
Total AFS securities	288,399	285,949
Gross Unrealized Gains	668	348
Gross Unrealized (Losses)	(41,610)	(44,678)
Total AFS securities, Estimated Fair Value	247,457	241,619
Commercial Mortgage-Backed Securities [Member] | Non-agency
Debt Securities, Available-for-sale Securities, Amortized Cost Basis [Abstract]
Total AFS securities	67,810	61,552
Gross Unrealized Gains	90	4
Gross Unrealized (Losses)	(1,923)	(2,110)
Total AFS securities, Estimated Fair Value	65,977	59,446
Residential Mortgage-Backed Securities [Member]
Debt Securities, Available-for-sale Securities, Amortized Cost Basis [Abstract]
Total AFS securities	1,602,571	1,578,270
Gross Unrealized Gains	3,387	2,047
Gross Unrealized (Losses)	(198,737)	(220,138)
Total AFS securities, Estimated Fair Value	1,407,221	1,360,179
Residential Mortgage-Backed Securities [Member] | Agency Securities [Member]
Debt Securities, Available-for-sale Securities, Amortized Cost Basis [Abstract]
Total AFS securities	1,506,416	1,478,648
Gross Unrealized Gains	2,917	1,375
Gross Unrealized (Losses)	(195,677)	(216,754)
Total AFS securities, Estimated Fair Value	1,313,656	1,263,269
Residential Mortgage-Backed Securities [Member] | Non-agency
Debt Securities, Available-for-sale Securities, Amortized Cost Basis [Abstract]
Total AFS securities	96,155	99,622
Gross Unrealized Gains	470	672
Gross Unrealized (Losses)	(3,060)	(3,384)
Total AFS securities, Estimated Fair Value	93,565	96,910
Collateralized Securities, Other [Member]
Debt Securities, Available-for-sale Securities, Amortized Cost Basis [Abstract]
Total AFS securities	1,885	1,860
Gross Unrealized Gains	0	0
Gross Unrealized (Losses)	0	0
Total AFS securities, Estimated Fair Value	$ 1,885	$ 1,860