v3.26.3
Derivative Financial Instruments (Details) - USD ($)
 3 Months Ended 9 Months Ended 12 Months Ended
Sep. 30, 2026
Sep. 30, 2025
Sep. 30, 2026
Sep. 30, 2025
Dec. 31, 2025
Derivative Financial Instruments          
Notional Amount $ 36,474,069,000   $ 36,474,069,000   $ 32,426,542,000
Estimated Fair Value Gain 119,731,000   119,731,000   222,886,000
Estimated Fair Value Loss 987,960,000   987,960,000   554,748,000
Fair value of the interest rate swap derivatives, other assets 117,900,000   117,900,000   221,700,000
Fair value of the interest rate swap derivatives, other liabilities 982,500,000   982,500,000   554,400,000
Reduction in derivative asset fair value     868,100,000   333,700,000
Estimated gain (loss) on fair value     5,200,000   69,000
Mortgage loan pipeline          
Obligation under forward commitments, the fair value of those obligations along with the fair value of derivative instruments associated with forward commitments          
Obligation 80,255,000   80,255,000   55,318,000
Expected closures          
Obligation under forward commitments, the fair value of those obligations along with the fair value of derivative instruments associated with forward commitments          
Obligation 73,661,000   73,661,000   48,106,000
Cash flow hedge | Borrower          
Derivative Financial Instruments          
Collateral provided 329,000,000   329,000,000    
Cash flow hedge | Counterparty          
Derivative Financial Instruments          
Collateral provided 64,300,000   64,300,000    
Cash flow hedge | Location, Statement of Financial Position, Balance [Axis]: us-gaap:InterestBearingDepositLiabilities | Counterparty          
Derivative Financial Instruments          
Cash collateral 46,600,000   46,600,000    
Interest rate contracts          
Derivative Financial Instruments          
Notional Amount 31,700,000,000   31,700,000,000   29,600,000,000
Mortgage servicing rights hedging | Non-designated hedges          
Derivative Financial Instruments          
Notional Amount 224,000,000   224,000,000   192,000,000
Estimated Fair Value Gain 0   0   69,000
Estimated Fair Value Loss 5,243,000   5,243,000    
Mortgage loan pipeline commitments hedging          
Obligation under forward commitments, the fair value of those obligations along with the fair value of derivative instruments associated with forward commitments          
Obligation 265,000   265,000   982,000
Mortgage loan pipeline commitments hedging | Non-designated hedges          
Derivative Financial Instruments          
Notional Amount 84,500,000   84,500,000   81,000,000
Estimated Fair Value Gain 1,810,000   1,810,000   982,000
Estimated Fair Value Loss 265,000   265,000   315,000
Forward commitments          
Derivative Financial Instruments          
Estimated Fair Value Loss 1,810,000   1,810,000   (315,000)
Obligation under forward commitments, the fair value of those obligations along with the fair value of derivative instruments associated with forward commitments          
Obligation 84,500,000   84,500,000   81,000,000
Interest rate swap          
Derivative Financial Instruments          
Net gain (loss) 1.2 $ (81,000) 2,400,000 $ (150,000,000)  
Interest rate swap | Fair Value Hedging | Counterparty          
Derivative Financial Instruments          
Notional Amount 2,615,000   2,615,000   2,615,000
Estimated Fair Value Gain 112,000   112,000   44,000
Amortized cost basis of loans hedged 2,600,000   2,600,000   2,600,000
Interest rate swap | Non-designated hedges | Borrower          
Derivative Financial Instruments          
Notional Amount 16,117,992,000   16,117,992,000   14,912,622,000
Estimated Fair Value Gain 9,495,000   9,495,000   143,879,000
Estimated Fair Value Loss 982,452,000   982,452,000   554,433,000
Interest rate swap | Non-designated hedges | Counterparty          
Derivative Financial Instruments          
Notional Amount 15,611,962,000   15,611,962,000   14,719,305,000
Estimated Fair Value Gain 108,448,000   108,448,000   77,799,000
Total gross derivative instruments, before netting, Notional amount 1,609,325,000   1,609,325,000   1,844,842,000
Total gross derivative instruments, before netting, Estimated fair value gain     124,550,000   81,240,000
Total gross derivative instruments, before netting, Estimated fair value loss     19,000   3,781,000
Less: Netting adjustment, Notional amount 19,723,000   19,723,000   221,941,000
Less: Netting adjustment, Estimated fair value gain     (19,000)   (3,781,000)
Less: Netting adjustment, Estimated fair value loss     (19,000)   (3,781,000)
Total gross derivative instruments, after netting, Notional amount 1,609,325,000   1,609,325,000   1,844,842,000
Total gross derivative instruments, after netting, Estimated fair value gain     124,531,000   77,459,000
Total gross derivative instruments, after netting, Estimated fair value loss     0   0
Master netting arrangement collateral obligation to return cash offset against derivative asset 46,600,000   46,600,000   25,900,000
Securities pledged 24,300,000   24,300,000   28,100,000
Master netting arrangement collateral obligation cash paid offset against derivative asset 2,400,000   2,400,000   1,700,000
Reduction in derivative asset fair value     868,100,000   333,700,000
Interest rate swap | Economic hedges | Counterparty          
Derivative Financial Instruments          
Notional Amount 4,433,000,000   4,433,000,000   2,519,000,000
Estimated Fair Value Gain $ (134,000)   $ (134,000)   $ 113,000