v3.26.1
Earnings per share - Schedule of Earnings Per Share (Details) - USD ($)
$ / shares in Units, $ in Thousands
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]        
Basic weighted average number of shares outstanding (in shares) 10,708,005 10,520,219 10,675,637 10,493,145
Net dilutive effect of share-based awards, treasury stock method (in shares) 775,281 828,830 705,123 815,834
Diluted weighted average number of shares outstanding (in shares) 11,483,286 11,349,049 11,380,760 11,308,979
Net income attributable to Oppenheimer Holdings Inc. $ 27,351 $ 21,674 $ 6,773 $ 52,329
Earnings per share attributable to Oppenheimer Holdings Inc. - Basic (in dollars per share) $ 2.55 $ 2.06 $ 0.63 $ 4.99
Earnings per share attributable to Oppenheimer Holdings Inc. - Diluted (in dollars per share) $ 2.38 $ 1.91 $ 0.60 $ 4.63
Class A Stock        
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]        
Number of anti-dilutive stock options granted (in shares) 0 199,850 0 202,475