EARNINGS PER SHARE (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended				9 Months Ended
	Jun. 30, 2012		Jun. 30, 2011		Jun. 30, 2012		Jun. 30, 2011
Earnings Per Share, Basic [Line Items]
Net (loss) income	$ (10,320)		$ 20,374		$ 101,572		$ 108,810
Basic earnings per share
Weighted average shares of common stock outstanding-basic	41,560		41,381		41,501		41,338
Basic (loss) earnings per common share	$ (0.25)		$ 0.49		$ 2.45		$ 2.63
Diluted earnings per share
Incremental shares	0	[1]	216	[1]	142	[1]	213	[1]
Weighted average shares of common stock outstanding-diluted	41,560		41,597		41,643		41,551
Diluted (loss) earnings per common share	$ (0.25)	[2]	$ 0.49	[2]	$ 2.44	[2]	$ 2.62	[2]
Antidilutive securities excluded from computation of earnings per share, amount	140

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

[2] Since there was a net loss for the three months ended June 30, 2012, incremental shares of 140 were not included in the computation of diluted loss per common share, as their effect would have been anti-dilutive. There were no anti-dilutive shares excluded from the calculation of diluted earnings per share for the nine months ended June 30, 2012 and the three and nine months ended June 30, 2011.