EARNINGS PER SHARE (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended				9 Months Ended
	Jun. 30, 2014		Jun. 30, 2013		Jun. 30, 2014		Jun. 30, 2013
Earnings Per Share [Abstract]
Net (loss) income	$ (14,274)		$ 29,155		$ 166,390		$ 134,830
Basic earnings per share
Weighted average shares of common stock outstanding-basic (in shares)	42,117,000		41,608,000		42,072,000		41,697,000
Basic (loss) earnings per common share (usd per share)	$ (0.34)		$ 0.70		$ 3.95		$ 3.23
Diluted earnings per share
Incremental shares	0	[1]	124,000	[1]	384,000	[1]	123,000	[1]
Weighted average shares of common stock outstanding-diluted (in shares)	42,117,000		41,732,000		42,456,000		41,820,000
Diluted earnings (loss) per common share (usd per share)	$ (0.34)	[2]	$ 0.70	[2]	$ 3.92	[2]	$ 3.22	[2]
Anti-dilutive shares excluded from the calculation of diluted earnings per share (in shares)	384,000		0		0		0

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

[2] Since there was a net loss for the three months ended June 30, 2014, incremental shares of 384 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, 2014, and for the three and nine months ended June 30, 2013.