Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2015	Jul. 31, 2015
Document Information [Line Items]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2015
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	Q2
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		13,662,212
Class B Stock [Member]
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		99,680