Regulatory Requirements - Additional Information (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013
Regulatory Capital Requirements [Line Items]
Cash and securities segregated for regulatory and other purposes	$ 18,594,000	$ 36,323,000
Oppenheimer
Regulatory Capital Requirements [Line Items]
Required percentage of net capital to aggregate customer-related debit items	2.00%
Net capital	161,100,000
Actual percentage of net capital to aggregate customer-related debit items	12.63%
Excess capital	135,600,000
Freedom
Regulatory Capital Requirements [Line Items]
Net capital	4,500,000
Freedom maintain net capital equal to the greater	250,000
Aggregate indebtedness	6.67%
Net capital in excess of minimum required	4,300,000
Cash and securities segregated for regulatory and other purposes	17,700,000
Oppenheimer Europe Ltd
Regulatory Capital Requirements [Line Items]
Net capital	6,400,000
Net capital in excess of minimum required	2,200,000
Common Equity Tier 1 Ratio	10.74%
Common Equity Tier 1 Ratio Required	4.50%
Tier 1 Capital Ratio	10.74%
Tier 1 Capital Ratio Required	6.00%
Total Capital Ratio	12.16%
Total Capital Ratio Required	8.00%
Regulatory capital required to be maintained	4,200,000
Oppenheimer Investments Asia Ltd.
Regulatory Capital Requirements [Line Items]
Net capital	2,400,000
Net capital in excess of minimum required	2,000,000
Regulatory capital required to be maintained	$ 387,000