v3.26.1
Fair value measurements - Schedule of Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - USD ($)
$ in Thousands
Jun. 30, 2026
Dec. 31, 2025
Assets    
Deposits with clearing organizations $ 37,408 $ 27,996
Securities owned:    
Securities owned, at fair value 1,532,557 1,250,802
Investments 29,209 32,295
Loans 148 653
Derivative contracts    
Derivative contracts, total   34
Total 1,599,322 1,311,780
Securities sold but not yet purchased:    
Securities sold but not yet purchased, at fair value 250,824 175,712
Derivative contracts    
Derivative contracts, total 4,889 160
Total 255,713 175,872
U.S. Treasury securities    
Securities owned:    
Securities owned, at fair value 1,211,878 1,151,564
Securities sold but not yet purchased:    
Securities sold but not yet purchased, at fair value 229,891 155,518
U.S. Agency securities    
Securities owned:    
Securities owned, at fair value 6,153 5,925
Securities sold but not yet purchased:    
Securities sold but not yet purchased, at fair value 1 1
Sovereign obligations    
Securities owned:    
Securities owned, at fair value 740 1,223
Securities sold but not yet purchased:    
Securities sold but not yet purchased, at fair value 6,903 2,410
Corporate debt and other obligations    
Securities owned:    
Securities owned, at fair value 39,156 6,053
Securities sold but not yet purchased:    
Securities sold but not yet purchased, at fair value 561 1,965
Mortgage and other asset-backed securities    
Securities owned:    
Securities owned, at fair value 2,229 2,109
Municipal obligations    
Securities owned:    
Securities owned, at fair value 229,181 28,926
Convertible bonds    
Securities owned:    
Securities owned, at fair value 6,974 20,500
Securities sold but not yet purchased:    
Securities sold but not yet purchased, at fair value 7,642 6,096
Corporate equities    
Securities owned:    
Securities owned, at fair value 31,233 29,370
Securities sold but not yet purchased:    
Securities sold but not yet purchased, at fair value 5,826 9,722
Money markets    
Securities owned:    
Securities owned, at fair value 5,013 5,004
Other debt securities    
Securities owned:    
Securities owned, at fair value   128
Futures    
Derivative contracts    
Derivative contracts, total 4,889 133
TBAs    
Derivative contracts    
Derivative contracts, total   34
Derivative contracts    
Derivative contracts, total   27
Level 1    
Assets    
Deposits with clearing organizations 37,408 27,996
Securities owned:    
Securities owned, at fair value 1,246,941 1,184,764
Investments 1,622 1,600
Loans 0 0
Derivative contracts    
Derivative contracts, total   0
Total 1,285,971 1,214,360
Securities sold but not yet purchased:    
Securities sold but not yet purchased, at fair value 235,717 165,240
Derivative contracts    
Derivative contracts, total 4,889 133
Total 240,606 165,373
Level 1 | U.S. Treasury securities    
Securities owned:    
Securities owned, at fair value 1,211,878 1,151,564
Securities sold but not yet purchased:    
Securities sold but not yet purchased, at fair value 229,891 155,518
Level 1 | U.S. Agency securities    
Securities owned:    
Securities owned, at fair value 0 0
Securities sold but not yet purchased:    
Securities sold but not yet purchased, at fair value 0 0
Level 1 | Sovereign obligations    
Securities owned:    
Securities owned, at fair value 0 0
Securities sold but not yet purchased:    
Securities sold but not yet purchased, at fair value 0 0
Level 1 | Corporate debt and other obligations    
Securities owned:    
Securities owned, at fair value 0 0
Securities sold but not yet purchased:    
Securities sold but not yet purchased, at fair value 0 0
Level 1 | Mortgage and other asset-backed securities    
Securities owned:    
Securities owned, at fair value 0 0
Level 1 | Municipal obligations    
Securities owned:    
Securities owned, at fair value 0 0
Level 1 | Convertible bonds    
Securities owned:    
Securities owned, at fair value 0 0
Securities sold but not yet purchased:    
Securities sold but not yet purchased, at fair value 0 0
Level 1 | Corporate equities    
Securities owned:    
Securities owned, at fair value 30,063 28,200
Securities sold but not yet purchased:    
Securities sold but not yet purchased, at fair value 5,826 9,722
Level 1 | Money markets    
Securities owned:    
Securities owned, at fair value 5,000 5,000
Level 1 | Other debt securities    
Securities owned:    
Securities owned, at fair value   0
Level 1 | Futures    
Derivative contracts    
Derivative contracts, total 4,889 133
Level 1 | TBAs    
Derivative contracts    
Derivative contracts, total   0
Derivative contracts    
Derivative contracts, total   0
Level 2    
Assets    
Deposits with clearing organizations 0 0
Securities owned:    
Securities owned, at fair value 282,204 62,676
Investments 4,301 13,695
Loans 148 653
Derivative contracts    
Derivative contracts, total   34
Total 286,653 77,058
Securities sold but not yet purchased:    
Securities sold but not yet purchased, at fair value 15,107 10,472
Derivative contracts    
Derivative contracts, total 0 27
Total 15,107 10,499
Level 2 | U.S. Treasury securities    
Securities owned:    
Securities owned, at fair value 0 0
Securities sold but not yet purchased:    
Securities sold but not yet purchased, at fair value 0 0
Level 2 | U.S. Agency securities    
Securities owned:    
Securities owned, at fair value 6,153 5,925
Securities sold but not yet purchased:    
Securities sold but not yet purchased, at fair value 1 1
Level 2 | Sovereign obligations    
Securities owned:    
Securities owned, at fair value 740 1,223
Securities sold but not yet purchased:    
Securities sold but not yet purchased, at fair value 6,903 2,410
Level 2 | Corporate debt and other obligations    
Securities owned:    
Securities owned, at fair value 36,914 3,989
Securities sold but not yet purchased:    
Securities sold but not yet purchased, at fair value 561 1,965
Level 2 | Mortgage and other asset-backed securities    
Securities owned:    
Securities owned, at fair value 2,229 2,109
Level 2 | Municipal obligations    
Securities owned:    
Securities owned, at fair value 229,181 28,926
Level 2 | Convertible bonds    
Securities owned:    
Securities owned, at fair value 6,974 20,500
Securities sold but not yet purchased:    
Securities sold but not yet purchased, at fair value 7,642 6,096
Level 2 | Corporate equities    
Securities owned:    
Securities owned, at fair value 0 0
Securities sold but not yet purchased:    
Securities sold but not yet purchased, at fair value 0 0
Level 2 | Money markets    
Securities owned:    
Securities owned, at fair value 13 4
Level 2 | Other debt securities    
Securities owned:    
Securities owned, at fair value   0
Level 2 | Futures    
Derivative contracts    
Derivative contracts, total 0 0
Level 2 | TBAs    
Derivative contracts    
Derivative contracts, total   34
Derivative contracts    
Derivative contracts, total   27
Level 3    
Assets    
Deposits with clearing organizations 0 0
Securities owned:    
Securities owned, at fair value 3,412 3,362
Investments 23,286 17,000
Loans 0 0
Derivative contracts    
Derivative contracts, total   0
Total 26,698 20,362
Securities sold but not yet purchased:    
Securities sold but not yet purchased, at fair value 0 0
Derivative contracts    
Derivative contracts, total 0 0
Total 0 0
Level 3 | U.S. Treasury securities    
Securities owned:    
Securities owned, at fair value 0 0
Securities sold but not yet purchased:    
Securities sold but not yet purchased, at fair value 0 0
Level 3 | U.S. Agency securities    
Securities owned:    
Securities owned, at fair value 0 0
Securities sold but not yet purchased:    
Securities sold but not yet purchased, at fair value 0 0
Level 3 | Sovereign obligations    
Securities owned:    
Securities owned, at fair value 0 0
Securities sold but not yet purchased:    
Securities sold but not yet purchased, at fair value 0 0
Level 3 | Corporate debt and other obligations    
Securities owned:    
Securities owned, at fair value 2,242 2,064
Securities sold but not yet purchased:    
Securities sold but not yet purchased, at fair value 0 0
Level 3 | Mortgage and other asset-backed securities    
Securities owned:    
Securities owned, at fair value 0 0
Level 3 | Municipal obligations    
Securities owned:    
Securities owned, at fair value 0 0
Level 3 | Convertible bonds    
Securities owned:    
Securities owned, at fair value 0 0
Securities sold but not yet purchased:    
Securities sold but not yet purchased, at fair value 0 0
Level 3 | Corporate equities    
Securities owned:    
Securities owned, at fair value 1,170 1,170
Securities sold but not yet purchased:    
Securities sold but not yet purchased, at fair value 0 0
Level 3 | Money markets    
Securities owned:    
Securities owned, at fair value 0 0
Level 3 | Other debt securities    
Securities owned:    
Securities owned, at fair value   128
Level 3 | Futures    
Derivative contracts    
Derivative contracts, total $ 0 0
Level 3 | TBAs    
Derivative contracts    
Derivative contracts, total   0
Derivative contracts    
Derivative contracts, total   $ 0