RELINQUISHMENT AGREEMENT (Details) (USD $)	3 Months Ended		9 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Sep. 30, 2012	Sep. 30, 1998
RELINQUISHMENT AGREEMENT [Abstract]
Term of relinquishment agreement			15 years
Period following the end of the first three-month period after the relinquishment date upon which senior relinquishment payments start			25 days
Period following the end of the first six-month period after the relinquishment date upon which junior relinquishment payments start			25 days
Relinquishment payment rate as a percent of revenues			2.50%
Relinquishment liability	$ 92,600,000		$ 92,600,000		$ 120,800,000	$ 549,100,000
Accretion of discount to the relinquishment liability	1,243,000	2,062,000	3,730,000	6,186,000
Relinquishment Payments [Abstract]
Principal			27,951,000	28,756,000
Accretion of discount			3,927,000	5,935,000
Total relinquishment payments			31,900,000	34,700,000
Accrued relinquishment payments	$ 19,300,000		$ 19,300,000		$ 13,300,000