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.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(12))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(11))
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Total revenue from sale of goods and services rendered during the reporting period, in the normal course of business, reduced by sales returns and allowances, and sales discounts.

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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)
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Segment Information - Revenue from external customers and long lived assets (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Sep. 30, 2017
Segment information
Assets	$ 6,362,096		$ 6,439,988
Operating revenues	564,087	$ 368,590
United States
Segment information
Operating revenues	500,758	300,559
Argentina
Segment information
Operating revenues	48,829	48,082
Colombia
Segment information
Operating revenues	11,996	9,371
Other Foreign
Segment information
Operating revenues	2,504	10,578
Operating segment
Segment information
Assets	5,663,604		5,613,084
Operating revenues	564,307	368,798
Investments and corporate operations
Segment information
Assets	698,490		826,901
U.S. Land \| Operating segment
Segment information
Assets	4,956,429		4,967,074
Offshore \| Operating segment
Segment information
Assets	103,852		99,533
International Land \| Operating segment
Segment information
Assets	421,322		413,392
Other
Segment information
Operating revenues	5,867	3,111
Other \| Operating segment
Segment information
Assets	182,001		133,085
Operating revenues	6,087	$ 3,319
Continued operations
Segment information
Assets	6,362,094		6,439,985
Discontinued operations.
Segment information
Assets	$ 2		$ 3