XML 66 R72.htm IDEA: XBRL DOCUMENT
v2.4.0.6

Significant Concentrations (Schedule Of Purchasers Accounted More Than Ten Percent Of Total Sales) (Details) | Dec. 31, 2011 | Dec. 31, 2010 | Dec. 31, 2009
--- | --- | --- | ---
Texon L.P. [Member] |  |  |  |  |  |
Significant Concentrations [Line Items] |  |  |  |  |  |
Percentage of sales to total sales | 18.00% |  | 19.00% |  | 30.00% |
Plains All American Pipeline L.P. [Member] |  |  |  |  |  |
Significant Concentrations [Line Items] |  |  |  |  |  |
Percentage of sales to total sales | 16.00% |  | 28.00% |  |  | [1]
Enserco Energy Inc. [Member] |  |  |  |  |  |
Significant Concentrations [Line Items] |  |  |  |  |  |
Percentage of sales to total sales | 15.00% |  |  | [1] |  | [1]
Whiting Petroleum Corporation [Member] |  |  |  |  |  |
Significant Concentrations [Line Items] |  |  |  |  |  |
Percentage of sales to total sales |  | [1] | 11.00% |  |  | [1]
Tesoro Refining And Marketing Company [Member] |  |  |  |  |  |
Significant Concentrations [Line Items] |  |  |  |  |  |
Percentage of sales to total sales |  | [1] |  | [1] | 32.00% |
[1] | N/A Not applicable as the sales to these purchasers did not account for more than 10% of the Company's total sales for such respective periods.

X
- Details
Name: | oas_SignificantConcentrationsLineItems
Namespace Prefix: | oas_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The percentage of net product revenue to total net revenue from the sale of goods as of year end. + References No definition available. + Details
Name: | us-gaap_SalesRevenueGoodsNetPercentage
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant