XML 105 R50.htm IDEA: XBRL DOCUMENT
v3.19.3.a.u2

Summary of Significant Accounting Policies - Additional Information (Narrative) (Details) | 12 Months Ended
--- | ---
Dec. 31, 2019
Summary Of Significant Accounting Policies [Line Items] |
Cash equivalents maximum maturity period of highly liquid investments | 90 days
Minimum [Member] |
Summary Of Significant Accounting Policies [Line Items] |
Number of business days for related transactions | 1 day
Loan forgiven over service period | 3 years
Minimum [Member] | Furniture and Fixtures [Member] |
Summary Of Significant Accounting Policies [Line Items] |
Depreciation and amortization on straight-line basis | 3 years
Maximum [Member] |
Summary Of Significant Accounting Policies [Line Items] |
Number of business days for related transactions | 2 days
Loan forgiven over service period | 10 years
Maximum [Member] | Furniture and Fixtures [Member] |
Summary Of Significant Accounting Policies [Line Items] |
Depreciation and amortization on straight-line basis | 7 years
Securities |
Summary Of Significant Accounting Policies [Line Items] |
Number of business days for related transactions | 2 days
Commodities |
Summary Of Significant Accounting Policies [Line Items] |
Number of business days for related transactions | 1 day

X
- Definition Cash equivalents maximum maturity period of highly liquid investments. + References No definition available. + Details
Name: | opy_CashEquivalentsMaximumMaturityPeriodOfHighlyLiquidInvestments
Namespace Prefix: | opy_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Service period. + References No definition available. + Details
Name: | opy_ServicePeriod
Namespace Prefix: | opy_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Summary Of Significant Accounting Policies [Line Items] + References No definition available. + Details
Name: | opy_SummaryOfSignificantAccountingPoliciesLineItems
Namespace Prefix: | opy_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Transaction Settlement Period + References No definition available. + Details
Name: | opy_TransactionSettlementPeriod
Namespace Prefix: | opy_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment. + References No definition available. + Details
Name: | us-gaap_PropertyPlantAndEquipmentUsefulLife
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | srt_RangeAxis=srt_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PropertyPlantAndEquipmentByTypeAxis=us-gaap_FurnitureAndFixturesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_TransactionTypeAxis=opy_SecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_TransactionTypeAxis=opy_CommoditiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |