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Amount of write-down of assets recognized in the income statement. Includes, but is not limited to, losses from tangible assets, intangible assets and goodwill.

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- Definition

Amount of assets held-for-sale that are not part of a disposal group, expected to be sold within a year or the normal operating cycle, if longer.

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- Definition

The amount of expense recognized in the current period that reflects the allocation of the cost of tangible assets over the assets' useful lives. Includes production and non-production related depreciation.

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Amount of gain (loss) on sale or disposal of assets, including but not limited to property plant and equipment, intangible assets and equity in securities of subsidiaries or equity method investee.

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Loss recognized as a result of the initial and subsequent write-down of a long-lived asset's carrying amount to fair value.

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- Definition

The cash inflow from the sale of long-lived, physical assets that are used in the normal conduct of business to produce goods and services and not intended for resale.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Amount after accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business to produce goods and services and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

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The charge against earnings resulting from the aggregate write down of tangible assets from their carrying value to their fair value.

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PROPERTY, PLANT AND EQUIPMENT - Narrative (Details) $ in Thousands	3 Months Ended			6 Months Ended
	Mar. 31, 2021 USD ($) rig	Dec. 31, 2020 USD ($)	Mar. 31, 2020 USD ($)	Mar. 31, 2021 USD ($) rig	Mar. 31, 2020 USD ($)	Sep. 30, 2020 USD ($)
Property, Plant and Equipment [Line Items]
Depreciation expense	$ 104,600		$ 130,200	$ 209,700	$ 258,500
Abandonments included in depreciation	500		900	400	1,700
Assets held-for-sale	13,076			13,076		$ 0
Asset impairment charge	54,284		563,234	54,284	563,234
Property, plant and equipment, net	3,374,235			3,374,235		$ 3,646,341
Tangible asset impairment charges					83,500
(Gain) loss on sale of assets	(18,515)		10,310	$ (6,179)	14,589
Domestic and International Conventional, FlexRig3, and FlexRig4 Asset Groups
Property, Plant and Equipment [Line Items]
Property, plant and equipment, net			605,800		605,800
Tangible asset impairment charges			441,400		441,400
In-Process Drilling Equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, net			68,400		68,400
Tangible asset impairment charges					44,900
Rotational Inventory
Property, Plant and Equipment [Line Items]
Property, plant and equipment, net			$ 38,600		38,600
Tangible asset impairment charges					38,600
Inventory Scrap and Obsolete, Capital Spares
Property, Plant and Equipment [Line Items]
(Gain) loss on sale of assets	$ (23,000)
North America Solutions \| Domestic and International Conventional, FlexRig3, and FlexRig4 Asset Groups
Property, Plant and Equipment [Line Items]
Tangible asset impairment charges					292,400
North America Solutions \| In-Process Drilling Equipment
Property, Plant and Equipment [Line Items]
Tangible asset impairment charges					75,800
North America Solutions \| Domestic Non Super Spec Asset Group
Property, Plant and Equipment [Line Items]
Number of rigs, held-for -sale \| rig	68			68
Assets held-for-sale	$ 13,100			$ 13,100
International Solutions \| Domestic and International Conventional, FlexRig3, and FlexRig4 Asset Groups
Property, Plant and Equipment [Line Items]
Tangible asset impairment charges					149,000
International Solutions \| Rotational Inventory
Property, Plant and Equipment [Line Items]
Tangible asset impairment charges					$ 7,700
Offshore Gulf of Mexico
Property, Plant and Equipment [Line Items]
Property, plant and equipment, net		$ 2,800
(Gain) loss on sale of assets				$ 9,200
Total consideration		$ 12,000