Amount classified as assets attributable to disposal group held for sale or disposed of, expected to be disposed of within one year or the normal operating cycle, if longer.

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Name:	us-gaap_AssetsOfDisposalGroupIncludingDiscontinuedOperationCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Assets Held-for-Sale and Discontinued Operations (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Nov. 30, 2018	Dec. 31, 2017
Assets held-for-sale
Assets held for sale	$ 12,250		$ 37,052
Pipeline commitment			8,500
Assets Held-for-sale \| Oil and Gas
Assets held-for-sale
Assets held for sale			$ 25,900
Assets Held-for-sale \| Oil and Gas \| Canada Drilling
Assets held-for-sale
Operation consideration		$ 8,000
Pipeline commitment		$ 2,400