Amount of loss from the write-down of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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Name:	us-gaap_GoodwillImpairmentLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Impairment of Inventory and Long-Lived Assets for Discontinued Operations (Additional Disclosures) (Details)	3 Months Ended				12 Months Ended
	Dec. 31, 2016 USD ($)	Sep. 30, 2016 USD ($)	Jun. 30, 2016 USD ($)	Mar. 31, 2016 USD ($) segment	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Apr. 01, 2016 rig	Dec. 31, 2015 rig
Property, Plant and Equipment [Line Items]
Decrease in crude oil prices				21.00%
Number of segments tested for goodwill impairment \| segment				2
Goodwill impairment recognized \| $	$ 0	$ 0	$ 0	$ 0	$ 37,180,000	$ 0	$ 0
United States
Property, Plant and Equipment [Line Items]
Number of drilling rigs \| rig								450	698
Decrease in number of drilling rigs								35.50%