| Schedule of recorded amount of assets and liabilities measured at fair value on a recurring basis |
| | | | | | | | | | | | | | | | | | Quoted Prices | | | | | | | | | | | | In Active | | Significant | | | | | | | | | Markets | | Other | | Significant | | | | | | for Identical | | Observable | | Unobservable | | | | | | Assets | | Inputs | | Inputs | (Dollars in thousands) | | Fair Value | | (Level 1) | | (Level 2) | | (Level 3) | June 30, 2025: | | | | | | | | | | | | | Assets | | | | | | | | | | | | | Derivative financial instruments | | $ | 214,898 | | $ | — | | $ | 214,898 | | $ | — | Mortgage loans held for sale | | | 71,038 | | | — | | | 71,038 | | | — | Trading securities | | | 95,306 | | | — | | | 95,306 | | | — | Securities available for sale: | | | | | | | | | | | | | Residential mortgage-backed securities issued by U.S. government | | | | | | | | | | | | | agencies or sponsored enterprises | | | 1,523,879 | | | — | | | 1,523,879 | | | — | Residential collateralized mortgage-obligations issued by U.S. government | | | | | | | | | | | | | agencies or sponsored enterprises | | | 2,296,971 | | | — | | | 2,296,971 | | | — | Commercial mortgage-backed securities issued by U.S. government | | | | | | | | | | | | | agencies or sponsored enterprises | | | 581,492 | | | — | | | 581,492 | | | — | State and municipal obligations | | | 922,417 | | | — | | | 922,417 | | | — | Small Business Administration loan-backed securities | | | 576,514 | | | — | | | 576,514 | | | — | Corporate securities | | | 26,594 | | | — | | | 26,594 | | | — | Total securities available for sale | | | 5,927,867 | | | — | | | 5,927,867 | | | — | Mortgage servicing rights | | | 85,836 | | | — | | | — | | | 85,836 | SBA servicing asset | | | 5,801 | | | — | | | — | | | 5,801 | | | $ | 6,400,746 | | $ | — | | $ | 6,309,109 | | $ | 91,637 | Liabilities | | | | | | | | | | | | | Derivative financial instruments | | $ | 612,284 | | $ | — | | $ | 612,284 | | $ | — | | | | | | | | | | | | | | December 31, 2024: | | | | | | | | | | | | | Assets | | | | | | | | | | | | | Derivative financial instruments | | $ | 161,490 | | $ | — | | $ | 161,490 | | $ | — | Mortgage loans held for sale | | | 98,115 | | | — | | | 98,115 | | | — | Trading securities | | | 102,932 | | | — | | | 102,932 | | | — | Securities available for sale: | | | | | | | | | | | | | U.S. Treasuries | | | 10,656 | | | — | | | 10,656 | | | — | U.S. Government agencies | | | 150,418 | | | — | | | 150,418 | | | — | Residential mortgage-backed securities issued by U.S. government | | | | | | | | | | | | | agencies or sponsored enterprises | | | 1,377,525 | | | — | | | 1,377,525 | | | — | Residential collateralized mortgage-obligations issued by U.S. government | | | | | | | | | | | | | agencies or sponsored enterprises | | | 459,095 | | | — | | | 459,095 | | | — | Commercial mortgage-backed securities issued by U.S. government | | | | | | | | | | | | | agencies or sponsored enterprises | | | 1,040,555 | | | — | | | 1,040,555 | | | — | State and municipal obligations | | | 945,723 | | | — | | | 945,723 | | | — | Small Business Administration loan-backed securities | | | 310,112 | | | — | | | 310,112 | | | — | Corporate securities | | | 26,509 | | | — | | | 26,509 | | | — | Total securities available for sale | | | 4,320,593 | | | — | | | 4,320,593 | | | — | Mortgage servicing rights | | | 89,795 | | | — | | | — | | | 89,795 | SBA servicing asset | | | 6,028 | | | — | | | — | | | 6,028 | | | $ | 4,778,953 | | $ | — | | $ | 4,683,130 | | $ | 95,823 | Liabilities | | | | | | | | | | | | | Derivative financial instruments | | $ | 879,855 | | $ | — | | $ | 879,855 | | $ | — |
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| Schedule of estimated fair value, and related carrying amount, of the Company's financial instruments |
| | | | | | | | | | | | | | | | | | | Carrying | | Fair | | | | | | | | | | | (Dollars in thousands) | | Amount | | Value | | Level 1 | | Level 2 | | Level 3 | | June 30, 2025 | | | | | | | | | | | | | | | | | Financial assets: | | | | | | | | | | | | | | | | | Cash and cash equivalents | | $ | 3,464,106 | | $ | 3,464,106 | | $ | 3,464,106 | | $ | — | | $ | — | | Trading securities | | | 95,306 | | | 95,306 | | | — | | | 95,306 | | | — | | Investment securities | | | 8,431,345 | | | 8,067,102 | | | 274,869 | | | 7,709,615 | | | 82,618 | | Loans held for sale | | | 318,985 | | | 319,939 | | | — | | | 319,939 | | | — | | Loans, net of allowance for credit losses | | | 46,646,201 | | | 46,339,114 | | | — | | | — | | | 46,339,114 | | Accrued interest receivable | | | 227,556 | | | 227,556 | | | — | | | 34,054 | | | 193,502 | | Mortgage servicing rights | | | 85,836 | | | 85,836 | | | — | | | — | | | 85,836 | | SBA servicing asset | | | 5,801 | | | 5,801 | | | — | | | — | | | 5,801 | | Interest rate swap – non-designated hedge | | | 210,999 | | | 210,999 | | | — | | | 210,999 | | | — | | Other derivative financial instruments (mortgage banking related) | | | 3,899 | | | 3,899 | | | — | | | 3,899 | | | — | | Financial liabilities: | | | | | | | | | | | | | | | | | Deposits | | | | | | | | | | | | | | | | | Noninterest-bearing | | | 13,719,030 | | | 13,719,030 | | | — | | | 13,719,030 | | | — | | Interest-bearing other than time deposits | | | 32,269,471 | | | 32,269,471 | | | — | | | 32,269,471 | | | — | | Time deposits | | | 7,708,460 | | | 7,683,701 | | | — | | | 7,683,701 | | | — | | Federal funds purchased and securities sold under agreements to repurchase | | | 630,558 | | | 630,558 | | | — | | | 630,558 | | | — | | Corporate and subordinated debentures | | | 1,099,705 | | | 1,104,781 | | | — | | | 1,104,781 | | | — | | Other borrowings | | | — | | | — | | | — | | | — | | | — | | Accrued interest payable | | | 52,130 | | | 52,130 | | | — | | | 52,130 | | | — | | Interest rate swap – non-designated hedge | | | 611,310 | | | 611,310 | | | — | | | 611,310 | | | — | | Other derivative financial instruments (mortgage banking related) | | | 974 | | | 974 | | | — | | | 974 | | | — | | December 31, 2024 | | | | | | | | | | | | | | | | | Financial assets: | | | | | | | | | | | | | | | | | Cash and cash equivalents | | $ | 1,392,067 | | $ | 1,392,067 | | $ | 1,392,067 | | $ | — | | $ | — | | Trading securities | | | 102,932 | | | 102,932 | | | — | | | 102,932 | | | — | | Investment securities | | | 6,798,876 | | | 6,378,734 | | | 187,266 | | | 6,155,120 | | | 36,348 | | Loans held for sale | | | 279,426 | | | 281,662 | | | — | | | 281,662 | | | — | | Loans, net of allowance for credit losses | | | 33,437,647 | | | 32,448,618 | | | — | | | — | | | 32,448,618 | | Accrued interest receivable | | | 163,402 | | | 163,402 | | | — | | | 25,035 | | | 138,367 | | Mortgage servicing rights | | | 89,795 | | | 89,795 | | | — | | | — | | | 89,795 | | SBA servicing asset | | | 6,028 | | | 6,028 | | | — | | | — | | | 6,028 | | Interest rate swap – non-designated hedge | | | 160,407 | | | 160,407 | | | — | | | 160,407 | | | — | | Other derivative financial instruments (mortgage banking related) | | | 1,083 | | | 1,083 | | | — | | | 1,083 | | | — | | Financial liabilities: | | | | | | | | | | | | | | | | | Deposits | | | | | | | | | | | | | | | | | Noninterest-bearing | | | 10,192,117 | | | 10,192,117 | | | — | | | 10,192,117 | | | — | | Interest-bearing other than time deposits | | | 23,703,027 | | | 23,703,027 | | | — | | | 23,703,027 | | | — | | Time deposits | | | 4,165,722 | | | 4,145,687 | | | — | | | 4,145,687 | | | — | | Federal funds purchased and securities sold under agreements to repurchase | | | 514,912 | | | 514,912 | | | — | | | 514,912 | | | — | | Corporate and subordinated debentures | | | 391,534 | | | 377,616 | | | — | | | 377,616 | | | — | | Accrued interest payable | | | 40,739 | | | 40,739 | | | — | | | 40,739 | | | — | | Interest rate swap – non-designated hedge | | | 878,046 | | | 878,046 | | | — | | | 878,046 | | | — | | Other derivative financial instruments (mortgage banking related) | | | 1,809 | | | 1,809 | | | — | | | 1,809 | | | — | |
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