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Business Segment Information - Summarized Financial Information of Segments (Detail) (USD $) | 3 Months Ended | 12 Months Ended
--- | --- | ---
Dec. 31, 2014 | Sep. 30, 2014 | Jun. 30, 2014 | Mar. 31, 2014 | Dec. 31, 2013 | Sep. 30, 2013 | Jun. 30, 2013 | Mar. 31, 2013 | Dec. 31, 2014 | Dec. 31, 2013 | Dec. 31, 2012
Segment Reporting Information [Line Items] |  |  |  |  |  |  |  |  |  |  |
Total revenues | $ 299,672,000 us-gaap_OilAndGasRevenue | $ 368,659,000 us-gaap_OilAndGasRevenue | $ 372,378,000 us-gaap_OilAndGasRevenue | $ 349,519,000 us-gaap_OilAndGasRevenue | $ 333,615,000 us-gaap_OilAndGasRevenue | $ 305,498,000 us-gaap_OilAndGasRevenue | $ 254,582,000 us-gaap_OilAndGasRevenue | $ 248,304,000 us-gaap_OilAndGasRevenue | $ 1,390,228,000 us-gaap_OilAndGasRevenue | $ 1,141,999,000 us-gaap_OilAndGasRevenue | $ 686,668,000 us-gaap_OilAndGasRevenue
Operating income | 15,924,000 us-gaap_OperatingIncomeLoss | 134,103,000 us-gaap_OperatingIncomeLoss | 166,545,000 us-gaap_OperatingIncomeLoss | 329,080,000 us-gaap_OperatingIncomeLoss | 122,133,000 us-gaap_OperatingIncomeLoss | 150,862,000 us-gaap_OperatingIncomeLoss | 113,450,000 us-gaap_OperatingIncomeLoss | 117,953,000 us-gaap_OperatingIncomeLoss | 645,652,000 us-gaap_OperatingIncomeLoss | 504,398,000 us-gaap_OperatingIncomeLoss | 276,993,000 us-gaap_OperatingIncomeLoss
Other income (expense) |  |  |  |  |  |  |  |  | 168,816,000 us-gaap_NonoperatingIncomeExpense | (141,381,000)us-gaap_NonoperatingIncomeExpense | (31,119,000)us-gaap_NonoperatingIncomeExpense
Income before income taxes |  |  |  |  |  |  |  |  | 814,468,000 us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments | 363,017,000 us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments | 245,874,000 us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments
Total assets | 5,938,412,000 us-gaap_Assets |  |  |  | 4,711,924,000 us-gaap_Assets |  |  |  | 5,938,412,000 us-gaap_Assets | 4,711,924,000 us-gaap_Assets |
Depreciation, depletion and amortization |  |  |  |  |  |  |  |  | 412,334,000 us-gaap_DepreciationDepletionAndAmortization | 307,055,000 us-gaap_DepreciationDepletionAndAmortization | 206,734,000 us-gaap_DepreciationDepletionAndAmortization
Impairment of oil and gas properties |  |  |  |  |  |  |  |  | 47,238,000 us-gaap_ImpairmentOfOilAndGasProperties | 1,168,000 us-gaap_ImpairmentOfOilAndGasProperties | 3,581,000 us-gaap_ImpairmentOfOilAndGasProperties
Exploration and Production [Member] |  |  |  |  |  |  |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |  |  |  |  |  |  |
Total revenues |  |  |  |  |  |  |  |  | 1,304,004,000 us-gaap_OilAndGasRevenue / us-gaap_StatementBusinessSegmentsAxis = oas_ExplorationAndProductionMember | 1,084,412,000 us-gaap_OilAndGasRevenue / us-gaap_StatementBusinessSegmentsAxis = oas_ExplorationAndProductionMember | 670,491,000 us-gaap_OilAndGasRevenue / us-gaap_StatementBusinessSegmentsAxis = oas_ExplorationAndProductionMember
Well Services [Member] |  |  |  |  |  |  |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |  |  |  |  |  |  |
Total revenues |  |  |  |  |  |  |  |  | 267,384,000 us-gaap_OilAndGasRevenue / us-gaap_StatementBusinessSegmentsAxis = oas_WellServicingMember | 180,686,000 us-gaap_OilAndGasRevenue / us-gaap_StatementBusinessSegmentsAxis = oas_WellServicingMember | 82,481,000 us-gaap_OilAndGasRevenue / us-gaap_StatementBusinessSegmentsAxis = oas_WellServicingMember
Midstream Services [Member] |  |  |  |  |  |  |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |  |  |  |  |  |  |
Total revenues |  |  |  |  |  |  |  |  | 50,958,000 us-gaap_OilAndGasRevenue / us-gaap_StatementBusinessSegmentsAxis = oas_MidstreamServicesMember | 29,230,000 us-gaap_OilAndGasRevenue / us-gaap_StatementBusinessSegmentsAxis = oas_MidstreamServicesMember |
Operating Segments [Member] |  |  |  |  |  |  |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |  |  |  |  |  |  |
Total revenues |  |  |  |  |  |  |  |  | 1,390,228,000 us-gaap_OilAndGasRevenue / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember | 1,141,999,000 us-gaap_OilAndGasRevenue / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember | 686,668,000 us-gaap_OilAndGasRevenue / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember
Operating income |  |  |  |  |  |  |  |  | 645,652,000 us-gaap_OperatingIncomeLoss / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember | 504,398,000 us-gaap_OperatingIncomeLoss / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember | 276,993,000 us-gaap_OperatingIncomeLoss / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember
Other income (expense) |  |  |  |  |  |  |  |  | 168,816,000 us-gaap_NonoperatingIncomeExpense / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember | (141,381,000)us-gaap_NonoperatingIncomeExpense / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember | (31,119,000)us-gaap_NonoperatingIncomeExpense / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember
Income before income taxes |  |  |  |  |  |  |  |  | 814,468,000 us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember | 363,017,000 us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember | 245,874,000 us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember
Total assets | 5,938,412,000 us-gaap_Assets / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember |  |  |  | 4,711,924,000 us-gaap_Assets / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember |  |  |  | 5,938,412,000 us-gaap_Assets / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember | 4,711,924,000 us-gaap_Assets / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember | 2,528,794,000 us-gaap_Assets / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember
Capital expenditures |  |  |  |  |  |  |  |  | 1,572,593,000 oas_CapitalExpendituresCashandNonCash / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember | 2,506,298,000 oas_CapitalExpendituresCashandNonCash / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember | 1,148,573,000 oas_CapitalExpendituresCashandNonCash / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember
Depreciation, depletion and amortization |  |  |  |  |  |  |  |  | 412,334,000 us-gaap_DepreciationDepletionAndAmortization / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember | 307,055,000 us-gaap_DepreciationDepletionAndAmortization / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember | 206,734,000 us-gaap_DepreciationDepletionAndAmortization / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember
Impairment of oil and gas properties |  |  |  |  |  |  |  |  | 47,238,000 us-gaap_ImpairmentOfOilAndGasProperties / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember |  |
Operating Segments [Member] | Exploration and Production [Member] |  |  |  |  |  |  |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |  |  |  |  |  |  |
Total revenues |  |  |  |  |  |  |  |  | 1,304,004,000 us-gaap_OilAndGasRevenue / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember / us-gaap_StatementBusinessSegmentsAxis = oas_ExplorationAndProductionMember | 1,084,412,000 us-gaap_OilAndGasRevenue / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember / us-gaap_StatementBusinessSegmentsAxis = oas_ExplorationAndProductionMember | 670,491,000 us-gaap_OilAndGasRevenue / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember / us-gaap_StatementBusinessSegmentsAxis = oas_ExplorationAndProductionMember
Operating income |  |  |  |  |  |  |  |  | 610,850,000 us-gaap_OperatingIncomeLoss / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember / us-gaap_StatementBusinessSegmentsAxis = oas_ExplorationAndProductionMember | 473,178,000 us-gaap_OperatingIncomeLoss / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember / us-gaap_StatementBusinessSegmentsAxis = oas_ExplorationAndProductionMember | 276,740,000 us-gaap_OperatingIncomeLoss / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember / us-gaap_StatementBusinessSegmentsAxis = oas_ExplorationAndProductionMember
Other income (expense) |  |  |  |  |  |  |  |  | 168,741,000 us-gaap_NonoperatingIncomeExpense / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember / us-gaap_StatementBusinessSegmentsAxis = oas_ExplorationAndProductionMember | (141,397,000)us-gaap_NonoperatingIncomeExpense / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember / us-gaap_StatementBusinessSegmentsAxis = oas_ExplorationAndProductionMember | (31,120,000)us-gaap_NonoperatingIncomeExpense / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember / us-gaap_StatementBusinessSegmentsAxis = oas_ExplorationAndProductionMember
Income before income taxes |  |  |  |  |  |  |  |  | 779,591,000 us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember / us-gaap_StatementBusinessSegmentsAxis = oas_ExplorationAndProductionMember | 331,781,000 us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember / us-gaap_StatementBusinessSegmentsAxis = oas_ExplorationAndProductionMember | 245,620,000 us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember / us-gaap_StatementBusinessSegmentsAxis = oas_ExplorationAndProductionMember
Total assets | 5,802,295,000 us-gaap_Assets / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember / us-gaap_StatementBusinessSegmentsAxis = oas_ExplorationAndProductionMember |  |  |  | 4,592,140,000 us-gaap_Assets / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember / us-gaap_StatementBusinessSegmentsAxis = oas_ExplorationAndProductionMember |  |  |  | 5,802,295,000 us-gaap_Assets / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember / us-gaap_StatementBusinessSegmentsAxis = oas_ExplorationAndProductionMember | 4,592,140,000 us-gaap_Assets / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember / us-gaap_StatementBusinessSegmentsAxis = oas_ExplorationAndProductionMember | 2,493,364,000 us-gaap_Assets / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember / us-gaap_StatementBusinessSegmentsAxis = oas_ExplorationAndProductionMember
Capital expenditures |  |  |  |  |  |  |  |  | 1,525,168,000 oas_CapitalExpendituresCashandNonCash / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember / us-gaap_StatementBusinessSegmentsAxis = oas_ExplorationAndProductionMember | 2,514,737,000 oas_CapitalExpendituresCashandNonCash / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember / us-gaap_StatementBusinessSegmentsAxis = oas_ExplorationAndProductionMember | 1,150,439,000 oas_CapitalExpendituresCashandNonCash / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember / us-gaap_StatementBusinessSegmentsAxis = oas_ExplorationAndProductionMember
Depreciation, depletion and amortization |  |  |  |  |  |  |  |  | 406,960,000 us-gaap_DepreciationDepletionAndAmortization / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember / us-gaap_StatementBusinessSegmentsAxis = oas_ExplorationAndProductionMember | 304,388,000 us-gaap_DepreciationDepletionAndAmortization / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember / us-gaap_StatementBusinessSegmentsAxis = oas_ExplorationAndProductionMember | 206,127,000 us-gaap_DepreciationDepletionAndAmortization / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember / us-gaap_StatementBusinessSegmentsAxis = oas_ExplorationAndProductionMember
Impairment of oil and gas properties |  |  |  |  |  |  |  |  | 47,238,000 us-gaap_ImpairmentOfOilAndGasProperties / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember / us-gaap_StatementBusinessSegmentsAxis = oas_ExplorationAndProductionMember |  |
Operating Segments [Member] | Well Services [Member] |  |  |  |  |  |  |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |  |  |  |  |  |  |
Total revenues |  |  |  |  |  |  |  |  | 74,610,000 us-gaap_OilAndGasRevenue / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember / us-gaap_StatementBusinessSegmentsAxis = oas_WellServicingMember | 51,845,000 us-gaap_OilAndGasRevenue / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember / us-gaap_StatementBusinessSegmentsAxis = oas_WellServicingMember | 16,177,000 us-gaap_OilAndGasRevenue / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember / us-gaap_StatementBusinessSegmentsAxis = oas_WellServicingMember
Operating income |  |  |  |  |  |  |  |  | 70,878,000 us-gaap_OperatingIncomeLoss / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember / us-gaap_StatementBusinessSegmentsAxis = oas_WellServicingMember | 56,322,000 us-gaap_OperatingIncomeLoss / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember / us-gaap_StatementBusinessSegmentsAxis = oas_WellServicingMember | 17,798,000 us-gaap_OperatingIncomeLoss / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember / us-gaap_StatementBusinessSegmentsAxis = oas_WellServicingMember
Other income (expense) |  |  |  |  |  |  |  |  | 75,000 us-gaap_NonoperatingIncomeExpense / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember / us-gaap_StatementBusinessSegmentsAxis = oas_WellServicingMember | 16,000 us-gaap_NonoperatingIncomeExpense / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember / us-gaap_StatementBusinessSegmentsAxis = oas_WellServicingMember | 1,000 us-gaap_NonoperatingIncomeExpense / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember / us-gaap_StatementBusinessSegmentsAxis = oas_WellServicingMember
Income before income taxes |  |  |  |  |  |  |  |  | 70,953,000 us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember / us-gaap_StatementBusinessSegmentsAxis = oas_WellServicingMember | 56,338,000 us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember / us-gaap_StatementBusinessSegmentsAxis = oas_WellServicingMember | 17,799,000 us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember / us-gaap_StatementBusinessSegmentsAxis = oas_WellServicingMember
Total assets | 281,844,000 us-gaap_Assets / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember / us-gaap_StatementBusinessSegmentsAxis = oas_WellServicingMember |  |  |  | 78,359,000 us-gaap_Assets / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember / us-gaap_StatementBusinessSegmentsAxis = oas_WellServicingMember |  |  |  | 281,844,000 us-gaap_Assets / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember / us-gaap_StatementBusinessSegmentsAxis = oas_WellServicingMember | 78,359,000 us-gaap_Assets / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember / us-gaap_StatementBusinessSegmentsAxis = oas_WellServicingMember | 63,875,000 us-gaap_Assets / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember / us-gaap_StatementBusinessSegmentsAxis = oas_WellServicingMember
Capital expenditures |  |  |  |  |  |  |  |  | 37,292,000 oas_CapitalExpendituresCashandNonCash / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember / us-gaap_StatementBusinessSegmentsAxis = oas_WellServicingMember | 15,217,000 oas_CapitalExpendituresCashandNonCash / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember / us-gaap_StatementBusinessSegmentsAxis = oas_WellServicingMember | 15,679,000 oas_CapitalExpendituresCashandNonCash / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember / us-gaap_StatementBusinessSegmentsAxis = oas_WellServicingMember
Depreciation, depletion and amortization |  |  |  |  |  |  |  |  | 14,080,000 us-gaap_DepreciationDepletionAndAmortization / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember / us-gaap_StatementBusinessSegmentsAxis = oas_WellServicingMember | 7,150,000 us-gaap_DepreciationDepletionAndAmortization / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember / us-gaap_StatementBusinessSegmentsAxis = oas_WellServicingMember | 2,694,000 us-gaap_DepreciationDepletionAndAmortization / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember / us-gaap_StatementBusinessSegmentsAxis = oas_WellServicingMember
Operating Segments [Member] | Midstream Services [Member] |  |  |  |  |  |  |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |  |  |  |  |  |  |
Total revenues |  |  |  |  |  |  |  |  | 11,614,000 us-gaap_OilAndGasRevenue / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember / us-gaap_StatementBusinessSegmentsAxis = oas_MidstreamServicesMember | 5,742,000 us-gaap_OilAndGasRevenue / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember / us-gaap_StatementBusinessSegmentsAxis = oas_MidstreamServicesMember |
Operating income |  |  |  |  |  |  |  |  | 22,730,000 us-gaap_OperatingIncomeLoss / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember / us-gaap_StatementBusinessSegmentsAxis = oas_MidstreamServicesMember | 17,509,000 us-gaap_OperatingIncomeLoss / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember / us-gaap_StatementBusinessSegmentsAxis = oas_MidstreamServicesMember |
Income before income taxes |  |  |  |  |  |  |  |  | 22,730,000 us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember / us-gaap_StatementBusinessSegmentsAxis = oas_MidstreamServicesMember | 17,509,000 us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember / us-gaap_StatementBusinessSegmentsAxis = oas_MidstreamServicesMember |
Total assets | 212,685,000 us-gaap_Assets / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember / us-gaap_StatementBusinessSegmentsAxis = oas_MidstreamServicesMember |  |  |  | 117,641,000 us-gaap_Assets / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember / us-gaap_StatementBusinessSegmentsAxis = oas_MidstreamServicesMember |  |  |  | 212,685,000 us-gaap_Assets / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember / us-gaap_StatementBusinessSegmentsAxis = oas_MidstreamServicesMember | 117,641,000 us-gaap_Assets / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember / us-gaap_StatementBusinessSegmentsAxis = oas_MidstreamServicesMember |
Capital expenditures |  |  |  |  |  |  |  |  | 68,939,000 oas_CapitalExpendituresCashandNonCash / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember / us-gaap_StatementBusinessSegmentsAxis = oas_MidstreamServicesMember | 18,955,000 oas_CapitalExpendituresCashandNonCash / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember / us-gaap_StatementBusinessSegmentsAxis = oas_MidstreamServicesMember |
Depreciation, depletion and amortization |  |  |  |  |  |  |  |  | 3,744,000 us-gaap_DepreciationDepletionAndAmortization / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember / us-gaap_StatementBusinessSegmentsAxis = oas_MidstreamServicesMember | 2,780,000 us-gaap_DepreciationDepletionAndAmortization / us-gaap_ConsolidationItemsAxis = us-gaap_OperatingSegmentsMember / us-gaap_StatementBusinessSegmentsAxis = oas_MidstreamServicesMember |
Segment Reconciling Items [Member] | Well Services [Member] |  |  |  |  |  |  |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |  |  |  |  |  |  |
Total revenues |  |  |  |  |  |  |  |  | 192,774,000 us-gaap_OilAndGasRevenue / us-gaap_ConsolidationItemsAxis = us-gaap_MaterialReconcilingItemsMember / us-gaap_StatementBusinessSegmentsAxis = oas_WellServicingMember | 128,841,000 us-gaap_OilAndGasRevenue / us-gaap_ConsolidationItemsAxis = us-gaap_MaterialReconcilingItemsMember / us-gaap_StatementBusinessSegmentsAxis = oas_WellServicingMember | 66,304,000 us-gaap_OilAndGasRevenue / us-gaap_ConsolidationItemsAxis = us-gaap_MaterialReconcilingItemsMember / us-gaap_StatementBusinessSegmentsAxis = oas_WellServicingMember
Segment Reconciling Items [Member] | Midstream Services [Member] |  |  |  |  |  |  |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |  |  |  |  |  |  |
Total revenues |  |  |  |  |  |  |  |  | 39,344,000 us-gaap_OilAndGasRevenue / us-gaap_ConsolidationItemsAxis = us-gaap_MaterialReconcilingItemsMember / us-gaap_StatementBusinessSegmentsAxis = oas_MidstreamServicesMember | 23,488,000 us-gaap_OilAndGasRevenue / us-gaap_ConsolidationItemsAxis = us-gaap_MaterialReconcilingItemsMember / us-gaap_StatementBusinessSegmentsAxis = oas_MidstreamServicesMember |
Intersegment Eliminations [Member] |  |  |  |  |  |  |  |  |  |  |
Segment Reporting Information [Line Items] |  |  |  |  |  |  |  |  |  |  |
Total revenues |  |  |  |  |  |  |  |  | (232,118,000)us-gaap_OilAndGasRevenue / us-gaap_ConsolidationItemsAxis = us-gaap_IntersegmentEliminationMember | (152,329,000)us-gaap_OilAndGasRevenue / us-gaap_ConsolidationItemsAxis = us-gaap_IntersegmentEliminationMember | (66,304,000)us-gaap_OilAndGasRevenue / us-gaap_ConsolidationItemsAxis = us-gaap_IntersegmentEliminationMember
Operating income |  |  |  |  |  |  |  |  | (58,806,000)us-gaap_OperatingIncomeLoss / us-gaap_ConsolidationItemsAxis = us-gaap_IntersegmentEliminationMember | (42,611,000)us-gaap_OperatingIncomeLoss / us-gaap_ConsolidationItemsAxis = us-gaap_IntersegmentEliminationMember | (17,545,000)us-gaap_OperatingIncomeLoss / us-gaap_ConsolidationItemsAxis = us-gaap_IntersegmentEliminationMember
Income before income taxes |  |  |  |  |  |  |  |  | (58,806,000)us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments / us-gaap_ConsolidationItemsAxis = us-gaap_IntersegmentEliminationMember | (42,611,000)us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments / us-gaap_ConsolidationItemsAxis = us-gaap_IntersegmentEliminationMember | (17,545,000)us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesMinorityInterestAndIncomeLossFromEquityMethodInvestments / us-gaap_ConsolidationItemsAxis = us-gaap_IntersegmentEliminationMember
Total assets | (358,412,000)us-gaap_Assets / us-gaap_ConsolidationItemsAxis = us-gaap_IntersegmentEliminationMember |  |  |  | (76,216,000)us-gaap_Assets / us-gaap_ConsolidationItemsAxis = us-gaap_IntersegmentEliminationMember |  |  |  | (358,412,000)us-gaap_Assets / us-gaap_ConsolidationItemsAxis = us-gaap_IntersegmentEliminationMember | (76,216,000)us-gaap_Assets / us-gaap_ConsolidationItemsAxis = us-gaap_IntersegmentEliminationMember | (28,445,000)us-gaap_Assets / us-gaap_ConsolidationItemsAxis = us-gaap_IntersegmentEliminationMember
Capital expenditures |  |  |  |  |  |  |  |  | (58,806,000)oas_CapitalExpendituresCashandNonCash / us-gaap_ConsolidationItemsAxis = us-gaap_IntersegmentEliminationMember | (42,611,000)oas_CapitalExpendituresCashandNonCash / us-gaap_ConsolidationItemsAxis = us-gaap_IntersegmentEliminationMember | (17,545,000)oas_CapitalExpendituresCashandNonCash / us-gaap_ConsolidationItemsAxis = us-gaap_IntersegmentEliminationMember
Depreciation, depletion and amortization |  |  |  |  |  |  |  |  | $ (12,450,000)us-gaap_DepreciationDepletionAndAmortization / us-gaap_ConsolidationItemsAxis = us-gaap_IntersegmentEliminationMember | $ (7,263,000)us-gaap_DepreciationDepletionAndAmortization / us-gaap_ConsolidationItemsAxis = us-gaap_IntersegmentEliminationMember | $ (2,087,000)us-gaap_DepreciationDepletionAndAmortization / us-gaap_ConsolidationItemsAxis = us-gaap_IntersegmentEliminationMember

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- Definition Sum of the carrying amounts as of the balance sheet date of all assets that are recognized. Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.18) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 12 -Article 7 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 18 -Article 5 + Details
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- Definition The aggregate expense recognized in the current period that allocates the cost of tangible assets, intangible assets, or depleting assets to periods that benefit from use of the assets. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585 + Details
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- Definition The expense recorded to reduce the value of oil and gas assets consisting of proved properties and unproved properties as the estimate of future successful production from these properties is reduced. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -SubTopic 360 -Section 35 -Paragraph 11 -URI http://asc.fasb.org/extlink&oid=28370743&loc=d3e66150-109466 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 360 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=6391110&loc=d3e2921-110230 + Details
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- Definition Sum of operating profit and nonoperating income or expense before Income or Loss from equity method investments, income taxes, extraordinary items, and noncontrolling interest. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08.(h)(1)(i)) -URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690 + Details
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- Definition Aggregate revenue during the period related to oil and gas business activities. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.1) -URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -SubTopic 235 -Section 50 -Paragraph 23 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=8451039&loc=d3e62136-109447 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -SubTopic 235 -Section 50 -Paragraph 24 -URI http://asc.fasb.org/extlink&oid=8451039&loc=d3e62246-109447 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 1 -Article 5 + Details
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