v3.26.1
Fair Value of Financial Instruments (Fair Value of Assets and Liabilities Measured on Recurring Basis) (Details) - USD ($)
$ in Thousands
Mar. 31, 2026
Dec. 31, 2025
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Financial instruments owned $ 1,657,349 $ 1,427,835
Available-for-sale securities 1,588,549 1,593,390
Financial instruments sold, but not yet purchased, at fair value 924,385 793,626
U.S. Government Agency Securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Available-for-sale securities 2,386  
Corporate Fixed Income Securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Available-for-sale securities 334,705  
State and Municipal Securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Available-for-sale securities 2,326  
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 1,151,131 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 1,318 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 138 152
Fair Value, Recurring [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Available-for-sale securities 1,588,549 1,593,390
Investments 84,585 81,825
Derivative contracts, Assets 65,558 [1] 71,297 [2]
Cash equivalents measured at NAV 2,450 2,340
Total Assets 3,398,491 3,176,687
Financial instruments sold, but not yet purchased, at fair value 924,385 793,626
Derivative contracts, Liabilities 65,570 [3] 71,311 [4]
Total Liabilities 989,955 864,937
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 8,227 5,196
Financial instruments sold, but not yet purchased, at fair value   475,449
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 321,696 174,478
Available-for-sale securities 2,386 2,381
Financial instruments sold, but not yet purchased, at fair value 603,437  
Fair Value, Recurring [Member] | Asset-Backed Securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Financial instruments owned 132,752 143,723
Available-for-sale securities 96,545 109,256
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 332,056 295,570
Available-for-sale securities 334,705 375,750
Financial instruments sold, but not yet purchased, at fair value 155,972 145,582
Fair Value, Recurring [Member] | Corporate Equity Securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Financial instruments owned 60,180 55,312
Investments 36,530 34,937
Financial instruments sold, but not yet purchased, at fair value 9,248 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 222,931 174,579
Available-for-sale securities 2,326 2,326
Fair Value, Recurring [Member] | Auction Rate Securities [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments 554 551
Fair Value, Recurring [Member] | Other Investment [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments 14,366 [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 33,135 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 3,396,041 3,174,347
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 497,724 515,634
Available-for-sale securities 1,151,131 1,101,412
Financial instruments sold, but not yet purchased, at fair value 154,512 154,983
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 1,318 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 138 152
Sovereign Debt [Member] | Fair Value, Recurring [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Financial instruments owned 1,657,349 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 81,783 [7] 63,343 [8]
Financial instruments sold, but not yet purchased, at fair value 1,216 [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 12,879 15,490
Total Assets 73,558 76,401
Financial instruments sold, but not yet purchased, at fair value 612,560 491,699
Total Liabilities 612,560 491,699
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 8,227 5,196
Financial instruments sold, but not yet purchased, at fair value 603,437 475,449
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
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 52,452 55,198
Investments 12,879 15,490
Financial instruments sold, but not yet purchased, at fair value 9,123 16,250
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 60,679 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 1,588,549 1,593,390
Investments 4,240 1
Derivative contracts, Assets 65,558 [1] 71,297 [2]
Total Assets 3,178,862 2,970,560
Financial instruments sold, but not yet purchased, at fair value 310,609 300,691
Derivative contracts, Liabilities 65,570 [3] 71,311 [4]
Total Liabilities 376,179 372,002
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 321,696 174,478
Available-for-sale securities 2,386 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 132,252 139,683
Available-for-sale securities 96,545 109,256
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 332,056 295,053
Available-for-sale securities 334,705 375,750
Financial instruments sold, but not yet purchased, at fair value 155,972 145,582
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 7,728  
Investments 4,240 1
Financial instruments sold, but not yet purchased, at fair value 125 113
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 222,931 174,579
Available-for-sale securities 2,326 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 497,724 515,634
Available-for-sale securities 1,151,131 1,101,412
Financial instruments sold, but not yet purchased, at fair value 154,512 154,983
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 1,318 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 138 152
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 1,520,515 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 6,128 [7] 6,445 [8]
Financial instruments sold, but not yet purchased, at fair value [10]   13
Level 3 [Member] | Fair Value, Recurring [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments 34,331 33,557
Total Assets 110,486 94,609
Financial instruments sold, but not yet purchased, at fair value 1,216 1,236
Total Liabilities 1,216 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   114
Investments 19,411 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 554 551
Level 3 [Member] | Fair Value, Recurring [Member] | Other Investment [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Investments 14,366 [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 76,155 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 75,655 [7] 56,898 [8]
Financial instruments sold, but not yet purchased, at fair value $ 1,216 [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 condition.
[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 syndicated loans.
[10] Includes syndicated loans and state and municipal securities