BUSINESS SEGMENT AND GEOGRAPHIC INFORMATION - Income by Segment (Details) - USD ($) $ in Thousands	3 Months Ended
Dec. 31, 2018	Dec. 31, 2017
Segment information
Total Sales	$ 740,598	$ 564,087
Segment Operating Income (Loss)	84,676	29,687
Depreciation	141,460	143,267
U.S. Land
Segment information
Total Sales	624,823	461,640
Offshore
Segment information
Total Sales	36,910	33,366
International Land
Segment information
Total Sales	66,287
Technologies
Segment information
Total Sales	9,920	2,849
Other..
Segment information
Total Sales	3,474	3,238
Operating segment
Segment information
Total Sales	740,598	564,087
Segment Operating Income (Loss)	84,676	29,687
Operating segment \| U.S. Land
Segment information
Total Sales	624,241	461,640
Segment Operating Income (Loss)	79,668	24,745
Operating segment \| Offshore
Segment information
Total Sales	36,910	33,366
Segment Operating Income (Loss)	7,168	8,725
Operating segment \| International Land
Segment information
Total Sales	66,287	63,214
Segment Operating Income (Loss)	6,630	3,534
Operating segment \| Technologies
Segment information
Total Sales	9,920	2,849
Segment Operating Income (Loss)	(10,344)	(8,815)
Operating segment \| Other..
Segment information
Total Sales	3,240	3,018
Segment Operating Income (Loss)	1,554	1,498
Inter-Segment
Segment information
Total Sales	(816)	(220)
Inter-Segment \| U.S. Land
Segment information
Total Sales	582
Inter-Segment \| Other..
Segment information
Total Sales	$ 234	$ 220

Amount of operating income (loss) attributed to the reportable segment.

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- Definition

The aggregate expense recognized in the current period that allocates the cost of tangible assets, intangible assets, or depleting assets to periods that benefit from use of the assets.

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- Definition

Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

+ References

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- Definition

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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