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

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481800/320-10-50-2

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- Definition

Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481800/320-10-50-2

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Amortized cost excluding accrued interest, before allowance for credit loss, of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 30
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479130/326-30-45-1

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Amount excluding accrued interest, of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 210
-Name Accounting Standards Codification
-Section S45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477657/942-210-S45-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 210
-Name Accounting Standards Codification
-Section S50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478478/942-210-S50-1

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(6))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478546/942-210-S99-1

Reference 4: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 326
-SubTopic 30
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479130/326-30-45-1

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