Consolidated Statements of Operations (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
REVENUE
Commissions									$ 469,829	$ 486,767	$ 469,865
Advisory fees									281,680	274,178	222,732
Investment banking									125,598	97,977	89,477
Interest									49,244	53,216	57,662
Principal transactions, net									29,699	43,768	54,311
Other									48,414	63,808	58,565
Total revenue	254,928	244,679	249,689	255,168	293,362	243,376	243,830	239,146	1,004,464	1,019,714	952,612
EXPENSES
Compensation and related expenses									664,641	675,936	626,411
Communications and technology									67,170	65,817	63,359
Occupancy and equipment costs									63,012	66,758	62,818
Clearing and exchange fees									24,709	24,481	23,750
Interest									17,801	26,142	35,086
Other									141,395	116,671	141,715
Total expenses									978,728	975,805	953,139
Income (loss) before income taxes	9,595	10,896	136	5,109	23,359	8,163	5,674	6,713	25,736	43,909	(527)
Income tax provision									16,175	17,756	324
Net income (loss) for the year									9,561	26,153	(851)
Less net income attributable to non-controlling interest									735	1,092	2,762
Net income (loss) attributable to Oppenheimer Holdings Inc.	$ 2,686	$ 4,470	$ (1,554)	$ 3,224	$ 13,313	$ 5,237	$ 2,848	$ 3,663	$ 8,826	$ 25,061	$ (3,613)
Earnings (loss) per share attributable to Oppenheimer Holdings Inc.
Basic, dollars per share	$ 0.20	$ 0.33	$ (0.11)	$ 0.24	$ 0.99	$ 0.38	$ 0.21	$ 0.27	$ 0.65	$ 1.85	$ (0.27)
Diluted, dollars per share	$ 0.19	$ 0.31	$ (0.11)	$ 0.23	$ 0.94	$ 0.37	$ 0.20	$ 0.26	$ 0.62	$ 1.77	$ (0.27)
Weighted average shares
Basic									13,604,258	13,577,725	13,602,205
Diluted									14,250,663	14,124,060	13,602,205