Condensed Consolidated Statements of Changes in Stockholders' Equity - USD ($) $ in Thousands	Total	Share Capital [Member]	Share Capital [Member] Class A Stock [Member]	Contributed Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income [Member]	Parent [Member]	Non-Controlling Interest [Member]
Balance at beginning of period at Dec. 31, 2013		$ 60,198		$ 42,407	$ 418,204	$ 1,709		$ 5,353
Issuance of Class A non-voting common stock			$ 2,199
Repurchase of Class A non-voting common stock for cancellation			0
Tax benefit (deficiency) from share-based awards				1,275
Share-based expense				4,445
Vested employee share plan awards				(4,177)
Net income for the period attributable to Oppenheimer Holdings Inc.	$ 6,140				6,140
Dividends paid ($0.33 per share)					(4,483)
Currency translation adjustment	(1,356)					(1,356)
Net income attributable to noncontrolling interest	(652)							652
Balance at end of period at Sep. 30, 2014	532,566	62,397		43,950	419,861	353	$ 526,561	6,005
Balance at beginning of period at Dec. 31, 2014	533,732	62,397		45,118	421,047	(918)		6,088
Issuance of Class A non-voting common stock			3,373
Repurchase of Class A non-voting common stock for cancellation			$ 6,618
Tax benefit (deficiency) from share-based awards				(235)
Share-based expense				3,289
Vested employee share plan awards				(5,056)
Net income for the period attributable to Oppenheimer Holdings Inc.	5,106				5,106
Dividends paid ($0.33 per share)					(4,531)
Currency translation adjustment	(166)					(166)
Net income attributable to noncontrolling interest	(883)							883
Balance at end of period at Sep. 30, 2015	$ 529,777	$ 59,152		$ 43,116	$ 421,622	$ (1,084)	$ 522,806	$ 6,971