CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY AND REDEEMABLE NONCONTROLLING INTERESTS (unaudited) - USD ($) $ in Thousands	Total	Class A Stock	Parent	Common stock ($0.001 par value per share)	Common stock ($0.001 par value per share) Class A Stock	Additional paid-in capital	Additional paid-in capital Class A Stock	Retained earnings		Retained earnings Class A Stock	Accumulated other comprehensive income	Noncontrolling interest
Increase (Decrease) in Temporary Equity [Roll Forward]
Common stock, par value (in dollars per share)	$ 0.001
Balance at beginning of period at Dec. 31, 2022				$ 11		$ 28,628		$ 764,178			$ 1,416	$ 722
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of Class A non-voting common stock					$ 0		$ 5,488
Repurchase of Class A non-voting common stock for cancellation		$ (3,700)			0		(3,687)			$ 0
Share-based expense						3,293
Vested employee share plan awards						(11,319)
Change in redemption value of redeemable noncontrolling interests	$ 165					(29)						(136)
Dividends paid								(1,674)
Currency translation adjustment	(497)										(497)
Net income (loss)	14,464							14,617	[1]			(153)
Balance at end of period at Mar. 31, 2023	800,858		$ 800,425	11		22,374		777,121			919	433
Balance at beginning of period at Dec. 31, 2022	25,466
Increase (Decrease) in Temporary Equity [Roll Forward]
Redemption of redeemable noncontrolling interests	(74)
Change in redemption value of redeemable noncontrolling interests	165					(29)						(136)
Balance at end of period at Mar. 31, 2023	$ 25,557
Increase (Decrease) in Temporary Equity [Roll Forward]
Dividends paid per share (in dollars per share)	$ 0.15
Balance at beginning of period at Dec. 31, 2022				11		28,628		764,178			1,416	722
Balance at end of period at Dec. 31, 2023	$ 789,239			10		31,774		756,468			914	73
Balance at beginning of period at Dec. 31, 2022	25,466
Balance at end of period at Dec. 31, 2023	$ 0
Increase (Decrease) in Temporary Equity [Roll Forward]
Common stock, par value (in dollars per share)	$ 0.001
Common stock, par value (in dollars per share)	$ 0.001
Issuance of Class A non-voting common stock					0		8,238
Repurchase of Class A non-voting common stock for cancellation		$ (8,400)			$ 0		$ (8,384)			$ 0
Share-based expense						3,145
Vested employee share plan awards						(14,996)
Change in redemption value of redeemable noncontrolling interests	$ 0					263						237
Dividends paid								(1,576)
Currency translation adjustment	(388)										(388)
Net income (loss)	25,744							26,054	[1]			(310)
Balance at end of period at Mar. 31, 2024	801,522		$ 801,522	$ 10		20,040		$ 780,946			$ 526	0
Increase (Decrease) in Temporary Equity [Roll Forward]
Redemption of redeemable noncontrolling interests	0
Change in redemption value of redeemable noncontrolling interests	0					$ 263						$ 237
Balance at end of period at Mar. 31, 2024	$ 0
Increase (Decrease) in Temporary Equity [Roll Forward]
Dividends paid per share (in dollars per share)	$ 0.15
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001

[1] (1) Attributable to Oppenheimer Holdings Inc.