Number of service provider.

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Amount of gain (loss) on sale or disposal of property, plant and equipment assets, including oil and gas property and timber property.

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Amount classified as liabilities attributable to disposal group held for sale or disposed of.

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The cash inflow to dispose of long-lived, physical assets and mineral interests in oil and gas properties used for normal oil and gas operations.

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Divestitures - Additional information (Details) $ in Thousands			1 Months Ended			3 Months Ended		6 Months Ended	9 Months Ended
	Oct. 01, 2018 USD ($)	Jul. 27, 2018 USD ($)	Nov. 13, 2018 USD ($)	Jul. 31, 2018 USD ($)	Jun. 30, 2018 USD ($)	Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2018 USD ($) ServiceProvider
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from asset dispositions					$ 6,913			$ 7,791	$ 36,335
(Loss) gain on sale of assets				$ 0		$ (2,024)	$ (13)	$ (876)	(2,599)
Other Non-core Assets
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from asset dispositions									$ 11,279
Oklahoma/Texas Panhandle
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from asset dispositions		$ 17,000
Conveyance in liabilities to buyer		$ 629
Kingfisher and Garfield Counties
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Service contracts term									15 years
Kingfisher and Garfield Counties \| Saltwater Disposal Infrastructure
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from asset dispositions									$ 8,299
Kingfisher, Garfield and Canadian Counties, Oklahoma
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of service provider \| ServiceProvider									2
Canadian County, Oklahoma
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Service contracts term									5 years
Subsequent Event \| Other Non-core Assets
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from asset dispositions	$ 5,989
Subsequent Event \| Kingfisher and Garfield Counties \| Saltwater Disposal Infrastructure
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from asset dispositions			$ 1,205