Earnings Per Share - Summary of Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended
		Mar. 31, 2017	Mar. 31, 2016
Earnings Per Share [Abstract]
Basic weighted average number of shares outstanding		13,399,250	13,379,827
Net dilutive effect of share-based awards, treasury method	[1]	0	0
Diluted weighted average number of shares outstanding		13,399,250	13,379,827
Net loss from continuing operations		$ (5,338)	$ (3,292)
Net income (loss) from discontinued operations		587	(617)
Net loss		(4,751)	(3,909)
Net income attributable to non-controlling interest, net of tax		96	(62)
Net loss attributable to Oppenheimer Holdings Inc.		$ (4,847)	$ (3,847)
Continuing operations (in dollars per share)		$ (0.40)	$ (0.25)
Discontinued operations (in dollars per share)		0.04	(0.04)
Net loss per share		(0.36)	(0.29)
Continuing operations (in dollars per share)		(0.40)	(0.25)
Discontinued operations (in dollars per share)		0.04	(0.04)
Net loss per share (in dollars per share)		$ (0.36)	$ (0.29)

[1] For the three months ended March 31, 2017, the diluted earnings per share computation does not include the anti-dilutive effect of 1,334,607 shares of Class A Stock granted under share-based compensation arrangements (1,295,972 shares for the three months ended March 31, 2016 ).(2)Represents net income (loss) from discontinued operations less net income (loss) attributable to noncontrolling interest, net of tax divided by weighted average number of shares outstanding.