XML 86 R80.htm IDEA: XBRL DOCUMENT v2.4.0.6

Consolidating Financial Statements - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2012
Condensed Financial Information [Line Items]
Ownership percentage, Guarantors	100.00%

X

- Details

Name:	oas_CondensedFinancialInformationLineItems
Namespace Prefix:	oas_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Ownership percentage, guarantor

+ References

No definition available.

+ Details

Name:	oas_OwnershipPercentageGuarantor
Namespace Prefix:	oas_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration