For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

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Amount after accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business to produce goods and services and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

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The total amount due to the entity within one year of the balance sheet date (or one operating cycle, if longer) from outside sources, including trade accounts receivable, notes and loans receivable, as well as any other types of receivables, net of allowances established for the purpose of reducing such receivables to an amount that approximates their net realizable value.

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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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SEGMENT INFORMATION - Income Reconciliation (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015
Segment information
Operating revenues	$ 532,304	$ 498,564	$ 405,283	$ 368,590	$ 331,708	$ 366,486	$ 438,191	$ 487,847	$ 1,804,741	$ 1,624,232	$ 3,161,702
Long-Lived Assets	5,001,051				5,144,733				5,001,051	5,144,733	$ 5,563,170
Accounts receivable, net of reserve	477,074				375,169				$ 477,074	$ 375,169
Operating revenues \| Customer concentration \| Customer one
Segment information
Concentration percentage									9.00%	8.00%	6.00%
Operating revenues \| Customer concentration \| Customer two
Segment information
Concentration percentage									9.00%	9.00%	5.00%
Receivables \| Credit concentration \| Customers one and two
Segment information
Accounts receivable, net of reserve	59,000				58,100				$ 59,000	$ 58,100
United States
Segment information
Operating revenues									1,591,769	1,386,786	$ 2,750,043
Long-Lived Assets	4,686,235				4,804,328				4,686,235	4,804,328	5,149,315
Argentina
Segment information
Operating revenues									157,257	159,427	177,984
Long-Lived Assets	155,978				183,286				155,978	183,286	211,862
Colombia
Segment information
Operating revenues									37,554	20,488	70,076
Long-Lived Assets	81,798				91,815				81,798	91,815	102,401
Ecuador
Segment information
Operating revenues									6	4,948	30,987
Long-Lived Assets	22,298				438				22,298	438	28,918
Other Foreign
Segment information
Operating revenues									18,155	52,583	132,612
Long-Lived Assets	$ 54,742				$ 64,866				54,742	64,866	70,674
Operating segment
Segment information
Operating revenues									$ 1,805,603	$ 1,625,087	$ 3,162,582