v3.26.1
Financial Instruments and Fair Value Measurements - Not Measured at Fair Value on Recurring Basis (Details) - USD ($)
$ in Thousands
Jun. 30, 2026
Dec. 31, 2025
Assets    
Cash restricted or segregated under regulations and other $ 63,759 $ 64,744
Receivables from broker-dealers and clearing organizations 3,207,464 1,896,405
Receivables from customers 309,953 161,561
Other assets 619,723 528,341
Liabilities    
Payables to broker-dealers and clearing organizations 1,036,371 998,276
Payables to customers 226,743 43,103
Quoted Prices in Active Markets for Identical Assets (Level 1)     
Assets    
Cash and cash equivalents 1,069,254 1,061,697
Cash restricted or segregated under regulations and other 63,759 64,744
Securities borrowed 0 0
Securities purchased under agreements to resell 0 0
Receivables from broker-dealers and clearing organizations 0 0
Receivables from customers 0 0
Other assets 14,574 16,414
Total Assets 1,147,587 1,142,855
Liabilities    
Short-term borrowings 0 0
Long-term borrowings 0 0
Securities loaned 0 0
Securities sold under agreements to repurchase 0 0
Payables to broker-dealers and clearing organizations 0 0
Payables to customers 0 0
Other liabilities 0 0
Total Liabilities 0 0
Significant Other Observable Inputs (Level 2)     
Assets    
Cash and cash equivalents 0 0
Cash restricted or segregated under regulations and other 0 0
Securities borrowed 3,774,108 3,191,138
Securities purchased under agreements to resell 1,857,034 988,929
Receivables from broker-dealers and clearing organizations 2,973,085 1,567,471
Receivables from customers 309,953 161,561
Other assets 39,109 23,531
Total Assets 8,953,289 5,932,630
Liabilities    
Short-term borrowings 355,359 12,382
Long-term borrowings 2,077,891 2,098,639
Securities loaned 4,089,659 3,477,831
Securities sold under agreements to repurchase 2,620,126 1,405,639
Payables to broker-dealers and clearing organizations 758,273 817,004
Payables to customers 226,743 43,103
Other liabilities 39,395 26,039
Total Liabilities 10,167,446 7,880,637
Significant Unobservable Inputs (Level 3)     
Assets    
Cash and cash equivalents 0 0
Cash restricted or segregated under regulations and other 0 0
Securities borrowed 0 0
Securities purchased under agreements to resell 0 0
Receivables from broker-dealers and clearing organizations 0 0
Receivables from customers 0 0
Other assets 0 0
Total Assets 0 0
Liabilities    
Short-term borrowings 0 0
Long-term borrowings 0 0
Securities loaned 0 0
Securities sold under agreements to repurchase 0 0
Payables to broker-dealers and clearing organizations 0 0
Payables to customers 0 0
Other liabilities 0 0
Total Liabilities 0 0
Carrying Value    
Assets    
Cash and cash equivalents 1,069,254 1,061,697
Cash restricted or segregated under regulations and other 63,759 64,744
Securities borrowed 3,774,108 3,191,138
Securities purchased under agreements to resell 1,857,034 988,929
Receivables from broker-dealers and clearing organizations 2,973,085 1,567,471
Receivables from customers 309,953 161,561
Other assets 53,683 39,945
Total Assets 10,100,876 7,075,485
Liabilities    
Short-term borrowings 353,941 12,382
Long-term borrowings 2,025,883 2,039,463
Securities loaned 4,089,659 3,477,831
Securities sold under agreements to repurchase 2,620,126 1,405,639
Payables to broker-dealers and clearing organizations 758,273 817,004
Payables to customers 226,743 43,103
Other liabilities 39,395 26,039
Total Liabilities 10,114,020 7,821,461
Fair Value    
Assets    
Cash and cash equivalents 1,069,254 1,061,697
Cash restricted or segregated under regulations and other 63,759 64,744
Securities borrowed 3,774,108 3,191,138
Securities purchased under agreements to resell 1,857,034 988,929
Receivables from broker-dealers and clearing organizations 2,973,085 1,567,471
Receivables from customers 309,953 161,561
Other assets 53,683 39,945
Total Assets 10,100,876 7,075,485
Liabilities    
Short-term borrowings 355,359 12,382
Long-term borrowings 2,077,891 2,098,639
Securities loaned 4,089,659 3,477,831
Securities sold under agreements to repurchase 2,620,126 1,405,639
Payables to broker-dealers and clearing organizations 758,273 817,004
Payables to customers 226,743 43,103
Other liabilities 39,395 26,039
Total Liabilities $ 10,167,446 $ 7,880,637