EARNINGS PER SHARE (Details) (USD $) In Thousands, except Share data	3 Months Ended				9 Months Ended
	Jun. 30, 2011		Jun. 30, 2010		Jun. 30, 2011		Jun. 30, 2010
Earnings Per Share, Basic [Line Items]
NET INCOME (LOSS)	$ 20,374		$ (10,177)		$ 108,810		$ 115,942
Basic earnings per share
Weighted average shares of common stock outstanding-basic	41,381,000		41,239,000		41,338,000		41,424,000
Basic earnings per common share	$ 0.49		$ (0.25)		$ 2.63		$ 2.8
Diluted earnings per share
Incremental shares	216,000	[1]	0	[1]	213,000	[1]	279,000	[1]
Weighted average shares of common stock outstanding-diluted	41,597,000		41,239,000		41,551,000		41,703,000
Diluted earnings per common share	$ 0.49	[2]	$ (0.25)	[2]	$ 2.62	[2]	$ 2.78	[2]
Antidilutive securities excluded from computation of earnings per share, amount	0		280,000		0		0

[1] Incremental shares consist of stock options, stock awards and performance units.

[2] There were no anti-dilutive shares excluded from the calculation of diluted earnings per share for the three months ended June 30, 2011 and nine months ended June 30, 2011, and 2010. Since there was a net loss for the three months ended June 30, 2010, incremental shares were not included in the computation of diluted loss per common share, as their effect would have been anti-dilutive.