XML 20 R57.htm IDEA: XBRL DOCUMENT v2.4.0.8

Condensed Consolidating Financial Information - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2014
Condensed Financial Information of Parent Company Only Disclosure [Abstract]
Ownership percentage, Guarantors	100.00%

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

X

- Details

Name:	us-gaap_CondensedFinancialInformationOfParentCompanyOnlyDisclosureAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration