Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
REVENUE
Commissions	$ 103,249	$ 79,409
Investment Advisory Fee Revenue	86,164	73,647
Investment banking	25,728	28,043
Proceeds from (Payments for) in Interest-bearing Deposits in Banks	18,826	33,968
Interest	10,890	12,727
Principal transactions, net	(868)	11,438
Other	(9,219)	12,538
Total revenue	234,770	251,770
EXPENSES
Compensation and related expenses	157,676	160,355
Communications and technology	19,891	20,086
Occupancy and equipment costs	16,078	15,273
Clearing and exchange fees	5,659	5,332
Interest	6,550	12,986
Other	18,693	21,686
Total expenses	224,547	235,718
Operating Income (Loss)	10,223	16,052
Income Tax Expense (Benefit)	2,405	4,858
Net income attributable to Oppenheimer Holdings Inc.	$ 7,818	$ 11,194
Net income per share
Net loss per share (in dollars per share)	$ 0.61	$ 0.86
Earnings Per Share, Diluted [Abstract]
Net loss per share (in dollars per share)	$ 0.58	$ 0.81
Weighted average shares
Basic (in shares)	12,895,729	13,020,344
Diluted (in shares)	13,456,233	13,851,321