v3.26.3
Fair Value Of Financial Instruments (Fair Value of Assets and Liabilities Measured on Recurring Basis) (Details) - USD ($)
$ in Thousands
Sep. 30, 2026
Dec. 31, 2025
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Financial instruments owned $ 1,821,512 $ 1,427,835
Available-for-sale securities 1,512,748 1,593,390
Financial instruments sold, but not yet purchased, at fair value 1,032,576 793,626
U.S. Government Agency Securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Available-for-sale securities 2,402  
Corporate Fixed Income Securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Available-for-sale securities 244,001  
State and Municipal Securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Available-for-sale securities 2,291  
Agency Mortgage-Backed Securities [Member] | Agency Securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Available-for-sale securities 1,200,549 1,101,412
Agency Mortgage-Backed Securities [Member] | Commercial [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Available-for-sale securities 1,243 2,113
Agency Mortgage-Backed Securities [Member] | Non-Agency [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Available-for-sale securities 124 152
Fair Value, Recurring [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Available-for-sale securities 1,512,748 1,593,390
Investments 85,944 81,825
Derivative contracts, Assets 99,373 [1] 71,297 [2]
Cash equivalents measured at NAV 3,146 2,340
Total Assets 3,522,723 3,176,687
Financial instruments sold, but not yet purchased, at fair value 1,032,576 793,626
Derivative contracts, Liabilities 99,379 [3] 71,311 [4]
Total Liabilities 1,131,955 864,937
Fair Value, Recurring [Member] | U.S. Government Agency Securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Financial instruments owned 199,035 174,478
Available-for-sale securities 2,402 2,381
Fair Value, Recurring [Member] | Asset-Backed Securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Financial instruments owned 262,969 143,723
Available-for-sale securities 62,138 109,256
Fair Value, Recurring [Member] | Corporate Fixed Income Securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Financial instruments owned 332,069 295,570
Available-for-sale securities 244,001 375,750
Financial instruments sold, but not yet purchased, at fair value 129,750 145,582
Fair Value, Recurring [Member] | Corporate Equity Securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Financial instruments owned 106,863 55,312
Investments 31,885 34,937
Financial instruments sold, but not yet purchased, at fair value 14,911 16,363
Fair Value, Recurring [Member] | State and Municipal Securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Financial instruments owned 302,955 174,579
Available-for-sale securities 2,291 2,326
Fair Value, Recurring [Member] | Auction Rate Securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments 184 551
Fair Value, Recurring [Member] | Other Investment [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments 14,905 [5] 13,560 [6]
Fair Value, Recurring [Member] | Investments in Funds and Partnerships Measured at NAV [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments 38,970 32,777
Fair Value, Recurring [Member] | Assets At Fair Value On Recurring Basis Before Cash Equivalents Measured at NAV [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Total Assets 3,519,577 3,174,347
Fair Value, Recurring [Member] | U.S. Government Securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Financial instruments owned 11,645 5,196
Financial instruments sold, but not yet purchased, at fair value 710,244 475,449
Fair Value, Recurring [Member] | Agency Mortgage-Backed Securities [Member] | Agency Securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Financial instruments owned 521,240 515,634
Available-for-sale securities 1,200,549 1,101,412
Financial instruments sold, but not yet purchased, at fair value 176,559 154,983
Fair Value, Recurring [Member] | Agency Mortgage-Backed Securities [Member] | Commercial [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Available-for-sale securities 1,243 2,113
Fair Value, Recurring [Member] | Agency Mortgage-Backed Securities [Member] | Non-Agency [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Available-for-sale securities 124 152
Sovereign Debt [Member] | Fair Value, Recurring [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Financial instruments owned 1,821,512 1,427,835
Other [Member] | Fair Value, Recurring [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Financial instruments owned 84,736 [7] 63,343 [8]
Syndicated Loans [Member] | Fair Value, Recurring [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Financial instruments sold, but not yet purchased, at fair value 1,112 [9] 1,249 [10]
Level 1 [Member] | Fair Value, Recurring [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments 9,339 15,490
Total Assets 82,274 76,401
Financial instruments sold, but not yet purchased, at fair value 725,055 491,699
Total Liabilities 725,055 491,699
Level 1 [Member] | Fair Value, Recurring [Member] | Corporate Fixed Income Securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Financial instruments owned 517 517
Level 1 [Member] | Fair Value, Recurring [Member] | Corporate Equity Securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Financial instruments owned 60,773 55,198
Investments 9,339 15,490
Financial instruments sold, but not yet purchased, at fair value 14,811 16,250
Level 1 [Member] | Fair Value, Recurring [Member] | U.S. Government Securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Financial instruments owned 11,645 5,196
Financial instruments sold, but not yet purchased, at fair value 710,244 475,449
Level 1 [Member] | Sovereign Debt [Member] | Fair Value, Recurring [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Financial instruments owned 72,935 60,911
Level 2 [Member] | Fair Value, Recurring [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Available-for-sale securities 1,512,748 1,593,390
Investments 3,422 1
Derivative contracts, Assets 99,373 [1] 71,297 [2]
Total Assets 3,301,479 2,970,560
Financial instruments sold, but not yet purchased, at fair value 307,150 300,691
Derivative contracts, Liabilities 99,379 [3] 71,311 [4]
Total Liabilities 406,529 372,002
Level 2 [Member] | Fair Value, Recurring [Member] | U.S. Government Agency Securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Financial instruments owned 199,035 174,478
Available-for-sale securities 2,402 2,381
Level 2 [Member] | Fair Value, Recurring [Member] | Asset-Backed Securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Financial instruments owned 262,469 139,683
Available-for-sale securities 62,138 109,256
Level 2 [Member] | Fair Value, Recurring [Member] | Corporate Fixed Income Securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Financial instruments owned 331,552 295,053
Available-for-sale securities 244,001 375,750
Financial instruments sold, but not yet purchased, at fair value 129,750 145,582
Level 2 [Member] | Fair Value, Recurring [Member] | Corporate Equity Securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Financial instruments owned 45,980 0
Investments 3,422 1
Financial instruments sold, but not yet purchased, at fair value 100 113
Level 2 [Member] | Fair Value, Recurring [Member] | State and Municipal Securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Financial instruments owned 302,955 174,579
Available-for-sale securities 2,291 2,326
Level 2 [Member] | Fair Value, Recurring [Member] | Agency Mortgage-Backed Securities [Member] | Agency Securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Financial instruments owned 521,240 515,634
Available-for-sale securities 1,200,549 1,101,412
Financial instruments sold, but not yet purchased, at fair value 176,559 154,983
Level 2 [Member] | Fair Value, Recurring [Member] | Agency Mortgage-Backed Securities [Member] | Commercial [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Available-for-sale securities 1,243 2,113
Level 2 [Member] | Fair Value, Recurring [Member] | Agency Mortgage-Backed Securities [Member] | Non-Agency [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Available-for-sale securities 124 152
Level 2 [Member] | Sovereign Debt [Member] | Fair Value, Recurring [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Financial instruments owned 1,685,936 1,305,872
Level 2 [Member] | Other [Member] | Fair Value, Recurring [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Financial instruments owned 22,705 [7] 6,445 [8]
Financial instruments sold, but not yet purchased, at fair value 741 [9] 13 [10]
Level 3 [Member] | Fair Value, Recurring [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments 34,213 33,557
Total Assets 96,854 94,609
Financial instruments sold, but not yet purchased, at fair value 371 1,236
Total Liabilities 371 1,236
Level 3 [Member] | Fair Value, Recurring [Member] | Asset-Backed Securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Financial instruments owned 500 4,040
Level 3 [Member] | Fair Value, Recurring [Member] | Corporate Equity Securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Financial instruments owned 110 114
Investments 19,124 19,446
Level 3 [Member] | Fair Value, Recurring [Member] | Auction Rate Securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments 184 551
Level 3 [Member] | Fair Value, Recurring [Member] | Other Investment [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments 14,905 [5] 13,560 [6]
Level 3 [Member] | Sovereign Debt [Member] | Fair Value, Recurring [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Financial instruments owned 62,641 61,052
Level 3 [Member] | Other [Member] | Fair Value, Recurring [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Financial instruments owned 62,031 [7] 56,898 [8]
Level 3 [Member] | Syndicated Loans [Member] | Fair Value, Recurring [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Financial instruments sold, but not yet purchased, at fair value $ 371 [9] $ 1,236 [10]
[1] Included in other assets in the consolidated statements of financial condition.
[2] Included in other assets in the consolidated statements of financial condition.
[3] Included in accounts payable and accrued expenses in the consolidated statements of financial condi
[4] Included in accounts payable and accrued expenses in the consolidated statements of financial condition.
[5] Primarily includes private company investments.
[6] Primarily includes private company investments.
[7] Includes syndicated loans and non-agency mortgage-backed securities.
[8] Includes syndicated loans, non-agency mortgage-backed securities, and sovereign debt.
[9] Includes asset-backed securities and syndicated loans.
[10] Includes syndicated loans and state and municipal securities.