Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2015	Oct. 30, 2015
Document Information [Line Items]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2015
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	Q3
Entity Registrant Name	OPPENHEIMER HOLDINGS INC
Entity Central Index Key	0000791963
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Class A Stock [Member]
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		13,333,368
Class B Stock [Member]
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		99,680