INVESTMENTS IN EQUITY INVESTEES - SCHEDULE OF EQUITY METHOD INVESTMENTS (Details) (USD $)	3 Months Ended
	Dec. 31, 2014 mi		Sep. 30, 2014
Schedule of Equity Method Investments [Line Items]
Investments in equity investees	$ 151,886,000		$ 153,010,000
Steckman Ridge [Member]
Schedule of Equity Method Investments [Line Items]
Investments in equity investees	127,907,000	[1]	128,413,000	[1]
Steckman Ridge [Member] | Equity Method Investee [Member]
Schedule of Equity Method Investments [Line Items]
Outstanding principal balance	70,400,000		70,400,000
Iroquois [Member]
Schedule of Equity Method Investments [Line Items]
Investments in equity investees	22,876,000		24,042,000
PennEast [Member]
Schedule of Equity Method Investments [Line Items]
Investments in equity investees	$ 1,103,000		$ 555,000
Construction plan, project area	108

[1] Includes loans with a total outstanding principal balance of $70.4 million for both December 31, 2014 and September 30, 2014. The loans accrue interest at a variable rate that resets quarterly and are due October 1, 2023.