v3.26.1
Fair Value of Financial Instruments (Estimated Fair Values and Fair Value Hierarchy of Financial Instruments not Recorded or Measured at Fair Value on a Nonrecurring Basis) (Details) - USD ($)
$ in Thousands
Mar. 31, 2026
Dec. 31, 2025
Dec. 31, 2024
 [4]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Securities purchased under agreements to resell [1] $ 746,375 $ 564,162  
Held-to-maturity securities [2] 6,850,934 6,565,484 [3]  
Securities sold under agreements to repurchase 862,954 [4] 651,236 $ 651,236
Fair Value, Measurements, Nonrecurring [Member]      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Cash 2,896,920 2,251,449  
Cash segregated for regulatory purposes 29,196 29,018  
Securities purchased under agreements to resell 746,375 564,162  
Held-to-maturity securities 6,850,934 6,565,484  
Bank loans 21,588,713 21,610,180  
Loans held for sale 348,331 502,199  
Securities sold under agreements to repurchase 862,954 651,236  
Bank deposits 30,797,148 29,752,095  
Senior notes 560,861 576,180  
Debentures to Stifel Financial Capital Trusts 51,285 51,582  
Fair Value, Measurements, Nonrecurring [Member] | Level 1 [Member]      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Cash 2,896,920 2,251,449  
Cash segregated for regulatory purposes 29,196 29,018  
Senior notes 560,861 576,180  
Fair Value, Measurements, Nonrecurring [Member] | Level 2 [Member]      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Securities purchased under agreements to resell 746,375 564,162  
Held-to-maturity securities 6,789,467 6,495,393  
Bank loans 21,505,798 21,515,785  
Loans held for sale 323,017 502,199  
Securities sold under agreements to repurchase 862,954 651,236  
Bank deposits 30,797,148 29,752,095  
Fair Value, Measurements, Nonrecurring [Member] | Level 3 [Member]      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Held-to-maturity securities 61,467 70,091  
Bank loans 82,915 94,395  
Loans held for sale 25,314    
Debentures to Stifel Financial Capital Trusts $ 51,285 $ 51,582  
[1] Available collateral includes securities received from the counterparty. These securities are not included on the consolidated statements of financial condition unless there is an event of default. The fair value of securities received as collateral was $744.2 million and $561.3 million at March 31, 2026 and December 31, 2025, respectively.
[2] Held-to-maturity securities are carried in the consolidated statements of financial condition at amortized cost, and the changes in the value of these securities, other than impairment charges, are not reported on the consolidated financial statements.
[3] Unrealized gains/(losses) related to available-for-sale securities are reported in accumulated other comprehensive income.
[4] Collateral pledged includes the fair value of securities pledged to the counterparty. These securities are included on the consolidated statements of financial condition unless we default. Collateral pledged by our company to the counterparty includes U.S. government agency securities, U.S. government securities, and corporate fixed income securities with market values of $901.1 million and $687.2 million at March 31, 2026 and December 31, 2025, respectively.