Consolidated Statements of Income - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
REVENUE
Commissions									$ 417,559	$ 469,829	$ 486,767
Advisory fees									280,247	281,680	274,178
Investment banking									102,540	125,598	97,977
Interest									51,031	49,244	53,216
Principal transactions, net									20,503	29,699	43,768
Other									56,505	48,414	63,808
Total revenue	$ 230,360	$ 213,536	$ 238,928	$ 245,561	$ 254,928	$ 244,679	$ 249,689	$ 255,168	928,385	1,004,464	1,019,714
EXPENSES
Compensation and related expenses									623,226	664,641	675,936
Communications and technology									66,910	67,170	65,817
Occupancy and equipment costs									63,144	63,012	66,758
Clearing and exchange fees									26,022	24,709	24,481
Interest									17,323	17,801	26,142
Other									125,049	141,395	116,671
Total expenses									921,674	978,728	975,805
Income before income tax provision	(4,243)	(1,527)	2,630	9,851	9,595	10,896	136	5,109	6,711	25,736	43,909
Income tax provision									3,813	16,175	17,756
Net income for the year									2,898	9,561	26,153
Less net income attributable to noncontrolling interest									936	735	1,092
Net income attributable to Oppenheimer Holdings Inc.	$ (3,144)	$ (908)	$ 295	$ 5,719	$ 2,686	$ 4,470	$ (1,554)	$ 3,224	$ 1,962	$ 8,826	$ 25,061
Earnings per share attributable to Oppenheimer Holdings Inc.
Basic earnings (loss) per share (in dollars per share)	$ (0.23)	$ (0.07)	$ 0.02	$ 0.42	$ 0.20	$ 0.33	$ (0.11)	$ 0.24	$ 0.14	$ 0.65	$ 1.85
Diluted earnings (loss) per share (in dollars per share)	$ (0.23)	$ (0.07)	$ 0.02	$ 0.40	$ 0.19	$ 0.31	$ (0.11)	$ 0.23	$ 0.14	$ 0.62	$ 1.77
Weighted average shares
Basic weighted average shares (in shares)									13,640,610	13,604,258	13,577,725
Diluted weighted average shares (in shares)									14,291,534	14,250,663	14,124,060