EARNINGS PER SHARE (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Dec. 31, 2012		Dec. 31, 2011
Earnings Per Share [Abstract]
Net income	$ 60,206		$ 57,357
Basic earnings per share
Weighted average shares of common stock outstanding-basic (in shares)	41,695		41,434
Basic (loss) earnings per common share (usd per share)	$ 1.44		$ 1.38
Diluted earnings per share
Incremental shares	63	[1]	217	[1]
Weighted average shares of common stock outstanding-diluted (in shares)	41,758		41,651
Diluted (loss) earnings per common share (usd per share)	$ 1.44	[2]	$ 1.38	[2]

[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 December 31, 2012 and 2011.