CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Statement of Comprehensive Income [Abstract]
Net (loss) income	$ (20,569)	$ 30,655
Other comprehensive income (loss), net of tax
Currency translation adjustment	213	(487)
Comprehensive (loss) income	(20,356)	30,168
Net income attributable to non-controlling interests	9	0
Comprehensive (loss) income attributable to Oppenheimer Holdings Inc.	$ (20,365)	$ 30,168