SEGMENT INFORMATION (Details 2) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2012
Segment information
Operating revenues	$ 985,038	$ 952,087	$ 893,430	$ 889,152	$ 864,536	$ 840,197	$ 838,309	$ 844,572	$ 3,719,707	$ 3,387,614	$ 3,151,802
Long-Lived Assets	5,188,544				4,676,103				5,188,544	4,676,103	4,351,571
Receivables	705,214				621,420				705,214	621,420
Operating revenues | Customer concentration | Customer one
Segment information
Concentration percentage									10.70%	9.50%	12.00%
Operating revenues | Customer concentration | Customer two
Segment information
Concentration percentage									8.20%	7.90%	10.20%
Receivables | Customer concentration
Segment information
Receivables	122,500				94,100				122,500	94,100
United States
Segment information
Operating revenues									3,338,365	3,011,760	2,864,570
Long-Lived Assets	4,753,844				4,345,950				4,753,844	4,345,950	4,039,770
Argentina
Segment information
Operating revenues									107,945	73,208	54,317
Long-Lived Assets	144,823				83,149				144,823	83,149	81,886
Colombia
Segment information
Operating revenues									85,176	100,052	82,247
Long-Lived Assets	107,112				81,315				107,112	81,315	84,389
Ecuador
Segment information
Operating revenues									69,195	67,890	56,448
Long-Lived Assets	70,742				63,894				70,742	63,894	38,265
Other foreign
Segment information
Operating revenues									119,026	134,704	94,220
Long-Lived Assets	$ 112,023				$ 101,795				$ 112,023	$ 101,795	$ 107,261