Collateralized transactions - Schedule of Disaggregation of Gross Obligations by Class (Details) - USD ($) $ in Thousands	Dec. 31, 2025	Dec. 31, 2024
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
U.S. Treasury securities	$ 1,172,957	$ 999,809
Equity securities	370,331	$ 235,498
Overnight and Open
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
U.S. Treasury securities	1,172,957
Equity securities	370,331
Gross amount of recognized liabilities for repurchase agreements and securities loaned	$ 1,543,288

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