Regulatory Requirements - Narrative (Details) (USD $)	3 Months Ended
Mar. 31, 2015
Oppenheimer [Member]
Regulatory Capital Requirements [Line Items]
Required percentage of net capital to aggregate customer-related debit items	2.00%
Initial capital	$ 147,100,000
Actual percentage of net capital to aggregate customer-related debit items	10.94%
Excess capital	120,200,000
Freedom [Member]
Regulatory Capital Requirements [Line Items]
Initial capital	6,000,000
Freedom maintain net capital equal to the greater	250,000
Aggregate indebtedness	6.67%
Net capital in excess of minimum required	5,800,000
Cash and securities segregated for regulatory and other purposes	662,000
Oppenheimer Investments Asia [Member]
Regulatory Capital Requirements [Line Items]
Initial capital	3,100,000
Net capital in excess of minimum required	2,700,000
Initial required capital	$ 386,000
Oppenheimer Europe Ltd [Member] \| Basel Three New Requirements [Member]
Regulatory Capital Requirements [Line Items]
Common equity Tier 1 capital ratio	10.43%
Common equity Tier 1 required	4.50%
Tier 1 capital ratio	10.43%
Tier 1 capital ratio required	6.00%
Total capital ratio	11.85%
Total capital ratio required	8.00%

Actual percentage of net capital to aggregate customer related debit items.

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- Definition

Common Equity Tier One Ratio required for capital adequacy purposes under the Capital Requirements Directive (DRD IV) in the European Union.

+ References

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Common Equity Tier 1 Ratio calculated for capital adequacy purposes under the Capital Requirements Directive (DRD IV) in the European Union.

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- Definition

Percentage of net capital to aggregate indebtedness.

+ References

No definition available.

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- Definition

Required percentage of net capital to aggregate customer related debit items.

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No definition available.

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- Definition

Tier One Capital Ratio calculated for capital adequacy purposes under the Capital Requirements Directive (DRD IV) in the European Union.

+ References

No definition available.

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Tier One Capital Ratio required for capital adequacy purposes under the Capital Requirements Directive (DRD IV) in the European Union.

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No definition available.

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- Definition

Total Capital Ratio calculated for capital adequacy purposes under the Capital Requirements Directive (DRD IV) in the European Union.

+ References

No definition available.

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Total Capital Ratio Required for capital adequacy purposes under the Capital Requirements Directive (DRD IV) in the European Union.

+ References

No definition available.

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- Definition

The amount of net capital in excess of the alternative minimum required net capital.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Rule 15c3-1

-Number 240

-Section 15c3-1

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- Definition

Cash deposited in a special reserve account for the exclusive benefit of customers pursuant to regulations other than SEC Regulations and the Commodity Exchange Act.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 305

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6478312&loc=d3e61473-112792

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- Definition

The amount of net capital in excess of the minimum required net capital.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Rule 15c3-1

-Number 240

-Section 15c3-1

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- Definition

Amount of minimum net capital required to be maintained to engage in securities transactions.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Rule 15c3-1

-Number 240

-Section 15c3-1

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- Definition

Minimum amount of net capital required to be maintained by entity's broker-dealer subsidiary to engage in securities transactions.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Rule 15c3-1

-Number 240

-Section 15c3-1

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- Definition

Net capital is equal to the net worth of the broker dealer, less certain items such as exchange memberships, carrying value of securities not readily marketable, haircuts on marketable securities in proprietary accounts, furniture and equipment and other illiquid assets as defined.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

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-Number 240

-Section 15c3-1

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