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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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
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Segment Information - Income Reconciliation (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2017	Mar. 31, 2016	Sep. 30, 2016
Segment information
Total assets	$ 6,538,184		$ 6,538,184		$ 6,832,019
Operating revenues	405,283	$ 438,191	773,873	$ 926,038	926,038
United States
Segment information
Operating revenues	370,526	385,977	671,085	795,483
Argentina
Segment information
Operating revenues	23,267	35,371	71,349	85,157
Colombia
Segment information
Operating revenues	8,852	4,602	18,223	11,345
Ecuador
Segment information
Operating revenues	1	527	2	4,467
Other Foreign
Segment information
Operating revenues	2,637	11,714	13,214	$ 29,586
Continued operations
Segment information
Total assets	6,538,148		6,538,148		6,831,955
Discontinued operations.
Segment information
Total assets	36		36		64
Other
Segment information
Operating revenues	3,324	3,231	6,435		7,199
Operating segment
Segment information
Total assets	5,491,205		5,491,205		5,633,773
Operating revenues	405,491	438,401	774,289		926,467
Operating segment \| U.S. Land
Segment information
Total assets	4,938,237		4,938,237		5,005,299
Operating segment \| Offshore
Segment information
Total assets	97,740		97,740		105,152
Operating segment \| International Land
Segment information
Total assets	419,354		419,354		487,181
Operating segment \| Other
Segment information
Total assets	35,874		35,874		36,141
Operating revenues	3,532	$ 3,441	6,851		7,628
Investments and corporate operations
Segment information
Total assets	$ 1,046,943		$ 1,046,943		$ 1,198,182