v3.26.1
INVESTMENT SECURITIES (Tables)
 6 Months Ended
Jun. 30, 2026
Investments, Debt and Equity Securities [Abstract]  
Schedule of Amortized Cost and Fair Value of Available-for-Sale and Held-to-Maturity Investment Securities Portfolio
The following table summarizes the amortized cost and fair value of the available-for-sale portfolio and the corresponding amounts of gross unrealized gains, unrealized losses, and basis adjustments in accumulated other comprehensive income (loss) (“AOCI”).
(dollars in thousands)Amortized
Cost		Unrealized
Gains		Unrealized
Losses
Basis
Adjustments (1)
Fair
Value
June 30, 2026    
Available-for-Sale    
U.S. Treasury$260,430 $— $(11,365)$(44,732)$204,333 
U.S. government-sponsored entities and agencies1,534,177 8 (139,013)(66,355)1,328,817 
Mortgage-backed securities - Agency10,076,294 36,276 (533,124)— 9,579,446 
States and political subdivisions318,074 1,262 (15,543)637 304,430 
Pooled trust preferred securities13,827 — (951)— 12,876 
Other securities156,568 750 (4,835)— 152,483 
Total available-for-sale securities$12,359,370 $38,296 $(704,831)$(110,450)$11,582,385 
December 31, 2025
Available-for-Sale
U.S. Treasury$269,313 $90 $(7,615)$(47,244)$214,544 
U.S. government-sponsored entities and agencies1,567,036 402 (134,795)(60,251)1,372,392 
Mortgage-backed securities - Agency9,575,241 79,999 (487,205)— 9,168,035 
States and political subdivisions438,642 2,275 (17,286)2,377 426,008 
Pooled trust preferred securities13,819 — (2,085)— 11,734 
Other securities195,946 1,138 (5,347)— 191,737 
Total available-for-sale securities$12,059,997 $83,904 $(654,333)$(105,118)$11,384,450 
(1)    Basis adjustments represent the amount of fair value hedging adjustments included in the carrying amounts of fixed-rate investment securities assets designated in fair value hedging arrangements. See Note 15 to the consolidated financial statements for additional information regarding these derivative financial instruments.
Schedule of Held-to-Maturity Investment Securities with Unrecognized Losses
The following table summarizes the amortized cost and fair value of the held-to-maturity investment securities portfolio and the corresponding amounts of gross unrecognized gains and losses.
(dollars in thousands)Amortized
Cost		Unrecognized
Gains		Unrecognized
Losses		Fair
Value
June 30, 2026   
Held-to-Maturity
U.S. government-sponsored entities and agencies$825,359 $— $(137,815)$687,544 
Mortgage-backed securities - Agency881,022 — (135,338)745,684 
States and political subdivisions1,138,273 580 (103,723)1,035,130 
Allowance for securities held-to-maturity(150)— — (150)
Total held-to-maturity securities$2,844,504 $580 $(376,876)$2,468,208 
December 31, 2025
Held-to-Maturity
U.S. government-sponsored entities and agencies$840,435 $— $(129,526)$710,909 
Mortgage-backed securities - Agency910,323 — (127,505)782,818 
States and political subdivisions1,144,880 853 (99,072)1,046,661 
Allowance for securities held-to-maturity(150)— — (150)
Total held-to-maturity securities$2,895,488 $853 $(356,103)$2,540,238 
The following table summarizes the held-to-maturity investment securities with unrecognized losses aggregated by major security type and length of time in a continuous loss position:
 Less than 12 months12 months or longerTotal
(dollars in thousands)Fair
Value		Unrecognized
Losses		Fair
Value		Unrecognized
Losses		Fair
Value		Unrecognized
Losses
June 30, 2026
Held-to-Maturity
U.S. government-sponsored entities
   and agencies		$— $— $687,544 $(137,815)$687,544 $(137,815)
Mortgage-backed securities - Agency— — 745,684 (135,338)745,684 (135,338)
States and political subdivisions38,340 (1,429)949,001 (102,294)987,341 (103,723)
Total held-to-maturity$38,340 $(1,429)$2,382,229 $(375,447)$2,420,569 $(376,876)
December 31, 2025
Held-to-Maturity
U.S. government-sponsored entities
   and agencies		$— $— $710,909 $(129,526)$710,909 $(129,526)
Mortgage-backed securities - Agency— — 782,818 (127,505)782,818 (127,505)
States and political subdivisions— — 995,331 (99,072)995,331 (99,072)
Total held-to-maturity$— $— $2,489,058 $(356,103)$2,489,058 $(356,103)
Schedule of Proceeds from Sales or Calls and Realized Gain and Losses of Available-for-Sale Investment Securities and Other Securities
Proceeds from sales or calls of available-for-sale investment securities and the resulting realized gains and realized losses were as follows:
Three Months Ended
June 30,		Six Months Ended
June 30,
(dollars in thousands)2026202520262025
Proceeds$43,667 $2,092,486 $203,343 $2,163,445 
Realized gains42 11 852 90 
Realized losses(76)(52)(811)(207)
Schedule of Expected Maturities of Investment Securities Portfolio
The table below shows the amortized cost and fair value of the investment securities portfolio by contractual maturity. Expected maturities may differ from contractual maturities if borrowers have the right to call or prepay obligations with or without call or prepayment penalties. Weighted average yield is based on amortized cost.
 June 30, 2026
(dollars in thousands)Amortized
Cost		Fair
Value		Weighted
Average
Yield
Maturity
Available-for-Sale   
Within one year$215,995 $215,925 4.83 %
One to five years3,718,906 3,615,549 4.12 
Five to ten years7,363,333 6,899,316 4.01 
Beyond ten years1,061,136 851,595 2.93 
Total$12,359,370 $11,582,385 3.97 %
Held-to-Maturity
Within one year$118 $113 2.28 %
One to five years55,759 51,623 2.03 
Five to ten years1,598,272 1,395,015 2.56 
Beyond ten years1,190,355 1,021,457 2.82 
Total$2,844,504 $2,468,208 2.66 %
Schedule of Available-for-Sale and Held-to-Maturity Investment Securities with Unrealized Losses by Aggregated Major Security Type and Length of Time in Continuous Unrealized Loss Position
The following table summarizes the available-for-sale investment securities with unrealized losses for which an allowance for credit losses has not been recorded by aggregated major security type and length of time in a continuous unrealized loss position:
 Less than 12 months12 months or longerTotal
(dollars in thousands)Fair
Value		Unrealized
Losses		Fair
Value		Unrealized
Losses		Fair
Value		Unrealized Losses
June 30, 2026
Available-for-Sale
U.S. Treasury$21,915 $(32)$182,418 $(11,333)$204,333 $(11,365)
U.S. government-sponsored entities
   and agencies		183,666 (1,636)1,143,200 (137,377)1,326,866 (139,013)
Mortgage-backed securities - Agency2,948,237 (29,525)2,927,560 (503,599)5,875,797 (533,124)
States and political subdivisions20,816 (142)146,548 (15,401)167,364 (15,543)
Pooled trust preferred securities— — 12,876 (951)12,876 (951)
Other securities12,679 (24)92,321 (4,811)105,000 (4,835)
Total available-for-sale$3,187,313 $(31,359)$4,504,923 $(673,472)$7,692,236 $(704,831)
December 31, 2025
Available-for-Sale
U.S. Treasury$— $— $184,175 $(7,615)$184,175 $(7,615)
U.S. government-sponsored entities
   and agencies		79,916 (78)1,173,044 (134,717)1,252,960 (134,795)
Mortgage-backed securities - Agency252,875 (953)3,157,476 (486,252)3,410,351 (487,205)
States and political subdivisions6,561 (17)234,389 (17,269)240,950 (17,286)
Pooled trust preferred securities— — 11,734 (2,085)11,734 (2,085)
Other securities1,766 (88)124,990 (5,259)126,756 (5,347)
Total available-for-sale$341,118 $(1,136)$4,885,808 $(653,197)$5,226,926 $(654,333)