Regulatory Requirements - Additional Information (Detail) (USD $)			6 Months Ended	3 Months Ended
	Jun. 30, 2014	Dec. 31, 2013	Jun. 30, 2014 Oppenheimer [Member]	Jun. 30, 2014 Freedom [Member]	Jun. 30, 2014 Oppenheimer Investments Asia [Member]	Jun. 30, 2014 Oppenheimer Europe Ltd [Member] Basel Three New Requirements [Member]
Regulatory Capital Requirements [Line Items]
Required percentage of net capital to aggregate customer-related debit items			2.00%
Initial capital			$ 157,400,000	$ 4,600,000	$ 2,800,000
Actual percentage of net capital to aggregate customer-related debit items			11.20%
Excess capital			129,300,000
Freedom maintain net capital equal to the greater				250,000
Aggregate indebtedness				6.67%
Net capital in excess of minimum required				4,300,000	2,400,000
Cash and securities segregated for regulatory and other purposes	19,117,000	36,323,000	14,500,000	18,300,000
Initial required capital					$ 387,000
Common equity Tier 1 capital ratio						9.54%
Common equity Tier 1 required						4.50%
Tier 1 capital ratio						9.54%
Tier 1 capital ratio required						6.00%
Total capital ratio						11.02%
Total capital ratio required						8.00%