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, 2020	[1]				$ 13			$ 80,801			$ 601,406			$ 3,448		$ 0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of Class A non-voting common stock	[1]						$ 0			$ 4,846
Repurchase of Class A non-voting common stock for cancellation	[1]						0			(4,715)			$ 0
Share-based expense	[1]							7,827
Vested employee share plan awards	[1]							(9,739)
Net income		$ 96,067									96,067	[1],[2]
Dividends paid	[1]										(4,936)
Currency translation adjustment		(64)												(64)	[1]
Capital distribution to noncontrolling interest	[1]															0
Net income (loss) attributable to noncontrolling interest		0														0	[1]
Balance at end of period at Sep. 30, 2021	[1]	774,954		$ 774,954	13			79,020			692,537			3,384		0
Balance at beginning of period at Dec. 31, 2020	[1]	0
Increase (Decrease) in Temporary Equity [Roll Forward]
Contributions during the year	[1]	0
Balance at end of period at Sep. 30, 2021	[1]	$ 0
Increase (Decrease) in Temporary Equity [Roll Forward]
Dividends paid per share (in dollars per share)	[1]	$ 0.39
Balance at beginning of period at Jun. 30, 2021	[1]				13			81,152			668,193			3,149		0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of Class A non-voting common stock	[1]						0			850
Repurchase of Class A non-voting common stock for cancellation	[1]						0			(4,715)			0
Share-based expense	[1]							2,608
Vested employee share plan awards	[1]							(875)
Net income		$ 26,250									26,250	[1],[2]
Dividends paid	[1]										(1,906)
Currency translation adjustment		235												235	[1]
Capital distribution to noncontrolling interest	[1]															0
Net income (loss) attributable to noncontrolling interest		0														0	[1]
Balance at end of period at Sep. 30, 2021	[1]	774,954		774,954	13			79,020			692,537			3,384		0
Balance at beginning of period at Jun. 30, 2021	[1]	0
Increase (Decrease) in Temporary Equity [Roll Forward]
Contributions during the year	[1]	0
Balance at end of period at Sep. 30, 2021	[1]	$ 0
Increase (Decrease) in Temporary Equity [Roll Forward]
Dividends paid per share (in dollars per share)	[1]	$ 0.15
Balance at beginning of period at Dec. 31, 2021		$ 825,265	[3]		12	[1]		78,034	[1]		740,926	[1]		4,225	[1]	2,069	[1]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of Class A non-voting common stock	[1]						0			2,862
Repurchase of Class A non-voting common stock for cancellation	[1]						(1)			(58,581)			(1,781)
Share-based expense	[1]							8,684
Vested employee share plan awards	[1]							(5,081)
Net income		9,938									9,938	[1],[2]
Dividends paid	[1]										(5,433)
Currency translation adjustment		(3,062)												(3,062)	[1]
Capital distribution to noncontrolling interest	[1]															(21)
Net income (loss) attributable to noncontrolling interest		(215)														(215)	[1]
Balance at end of period at Sep. 30, 2022	[1]	772,575		770,742	11			25,918			743,650			1,163		1,833
Balance at beginning of period at Dec. 31, 2021	[1],[3]	127,765
Increase (Decrease) in Temporary Equity [Roll Forward]
Contributions during the year	[1]	0
Balance at end of period at Sep. 30, 2022	[1]	$ 127,765
Increase (Decrease) in Temporary Equity [Roll Forward]
Dividends paid per share (in dollars per share)	[1]	$ 0.45
Balance at beginning of period at Jun. 30, 2022	[1]				11			35,461			742,614			1,573		1,709
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of Class A non-voting common stock	[1]						0			518
Repurchase of Class A non-voting common stock for cancellation	[1]						$ 0			$ (12,206)			$ (1,781)
Share-based expense	[1]							2,631
Vested employee share plan awards	[1]							(486)
Net income		$ 4,520									4,520	[1],[2]
Dividends paid	[1]										(1,703)
Currency translation adjustment		(410)												(410)	[1]
Capital distribution to noncontrolling interest	[1]															(21)
Net income (loss) attributable to noncontrolling interest		145														145	[1]
Balance at end of period at Sep. 30, 2022	[1]	772,575		$ 770,742	$ 11			$ 25,918			$ 743,650			$ 1,163		$ 1,833
Balance at beginning of period at Jun. 30, 2022	[1]	127,765
Increase (Decrease) in Temporary Equity [Roll Forward]
Contributions during the year	[1]	0
Balance at end of period at Sep. 30, 2022	[1]	$ 127,765
Increase (Decrease) in Temporary Equity [Roll Forward]
Dividends paid per share (in dollars per share)	[1]	$ 0.15

[1] (1) Certain prior period reported amounts were reclassified to conform to the current period presentation, See Note 2.

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

[3] Certain prior period reported amounts were reclassified to conform to the current period presentation, See Note 2