CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY AND REDEEMABLE NONCONTROLLING INTERESTS (unaudited) - USD ($) $ in Thousands	Total	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
Balance at beginning of period at Dec. 31, 2021			$ 12		$ 78,034		$ 740,926			$ 4,225	$ 2,069
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of Class A non-voting common stock				$ 0		$ 2,862
Repurchase of Class A non-voting common stock for cancellation				(1)		(58,581)			$ (1,781)
Share-based expense					8,684
Vested employee share plan awards					(5,081)
Change in redemption value of redeemable noncontrolling interests	$ 0				0						0
Net income	9,938						9,938	[1]
Dividends paid							(5,433)
Currency translation adjustment	(3,062)									(3,062)
Capital addition (distribution) to noncontrolling interest											(21)
Net income (loss) attributable to noncontrolling interest	(215)										(215)
Balance at end of period at Sep. 30, 2022	772,575	$ 770,742	11		25,918		743,650			1,163	1,833
Balance at beginning of period at Dec. 31, 2021	127,765
Increase (Decrease) in Temporary Equity [Roll Forward]
Redemption of redeemable noncontrolling interests	0
Change in redemption value of redeemable noncontrolling interests	0				0						0
Balance at end of period at Sep. 30, 2022	$ 127,765
Increase (Decrease) in Temporary Equity [Roll Forward]
Dividends paid per share (in dollars per share)	$ 0.45
Balance at beginning of period at Jun. 30, 2022			11		35,461		742,614			1,573	1,709
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of Class A non-voting common stock				0		518
Repurchase of Class A non-voting common stock for cancellation				0		(12,206)			(1,781)
Share-based expense					2,631
Vested employee share plan awards					(486)
Change in redemption value of redeemable noncontrolling interests	$ 0				0						0
Net income	4,520						4,520	[1]
Dividends paid							(1,703)
Currency translation adjustment	(410)									(410)
Capital addition (distribution) to noncontrolling interest											(21)
Net income (loss) attributable to noncontrolling interest	145										145
Balance at end of period at Sep. 30, 2022	772,575	770,742	11		25,918		743,650			1,163	1,833
Balance at beginning of period at Jun. 30, 2022	127,765
Increase (Decrease) in Temporary Equity [Roll Forward]
Redemption of redeemable noncontrolling interests	0
Change in redemption value of redeemable noncontrolling interests	0				0						0
Balance at end of period at Sep. 30, 2022	$ 127,765
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	$ 794,955		11		28,628		764,178			1,416	722
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of Class A non-voting common stock				0		6,040
Repurchase of Class A non-voting common stock for cancellation				(1)		(3,898)			(27,555)
Share-based expense					10,054
Vested employee share plan awards					(11,892)
Change in redemption value of redeemable noncontrolling interests	591				(106)						(485)
Net income	19,079						19,079	[1]
Dividends paid							(4,904)
Currency translation adjustment	(1,740)									(1,740)
Capital addition (distribution) to noncontrolling interest											171
Net income (loss) attributable to noncontrolling interest	(403)										(403)
Balance at end of period at Sep. 30, 2023	779,315	779,310	10		28,826		750,798			(324)	5
Balance at beginning of period at Dec. 31, 2022	25,466
Increase (Decrease) in Temporary Equity [Roll Forward]
Redemption of redeemable noncontrolling interests	(83)
Change in redemption value of redeemable noncontrolling interests	591				(106)						(485)
Balance at end of period at Sep. 30, 2023	$ 25,974
Increase (Decrease) in Temporary Equity [Roll Forward]
Dividends paid per share (in dollars per share)	$ 0.45
Balance at beginning of period at Jun. 30, 2023			11		25,576		762,471			256	109
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of Class A non-voting common stock				0		367
Repurchase of Class A non-voting common stock for cancellation				$ (1)		$ (211)			$ (23,956)
Share-based expense					3,413
Vested employee share plan awards					(314)
Change in redemption value of redeemable noncontrolling interests	$ 26				(5)						(22)
Net income	13,861						13,861	[1]
Dividends paid							(1,578)
Currency translation adjustment	(580)									(580)
Capital addition (distribution) to noncontrolling interest											0
Net income (loss) attributable to noncontrolling interest	(82)										(82)
Balance at end of period at Sep. 30, 2023	779,315	$ 779,310	$ 10		28,826		$ 750,798			$ (324)	5
Balance at beginning of period at Jun. 30, 2023	25,948
Increase (Decrease) in Temporary Equity [Roll Forward]
Redemption of redeemable noncontrolling interests	0
Change in redemption value of redeemable noncontrolling interests	26				$ (5)						$ (22)
Balance at end of period at Sep. 30, 2023	$ 25,974
Increase (Decrease) in Temporary Equity [Roll Forward]
Dividends paid per share (in dollars per share)	$ 0.15

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