COMMON STOCK EQUITY (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
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance as of beginning of period (shares)			41,961,534
Balance as of beginning of period			$ 887,384
Net income	(14,274)	29,155	166,390	134,830
Other comprehensive income	834	287	675	1,306
Common stock issued under stock plans			14,086
Tax benefits from stock plans			348
Cash dividend declared ($1.26 per share)			(53,024)
Treasury stock and other			(2,774)
Balance as of end of period (shares)	42,167,558		42,167,558
Balance as of end of period	1,013,085		1,013,085
Cash dividend declared per share (usd per share)	$ 0.42	$ 0.40	$ 1.26	$ 1.20
Common Stock [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance as of beginning of period (shares)			41,962,000
Balance as of beginning of period			112,563
Common stock issued under stock plans (shares)			324,000
Common stock issued under stock plans			214
Treasury stock and other (shares)			(118,000)
Balance as of end of period (shares)	42,168,000		42,168,000
Balance as of end of period	112,777		112,777
Premium on Common Stock [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance as of beginning of period			300,196
Common stock issued under stock plans			4,187
Tax benefits from stock plans			348
Balance as of end of period	304,731		304,731
Accumulated Other Comprehensive (Loss) Income [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance as of beginning of period			(1,621)
Other comprehensive income			675
Balance as of end of period	(946)		(946)
Treasury Stock And Other [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance as of beginning of period			(128,638)
Common stock issued under stock plans			9,685
Treasury stock and other			(2,774)
Balance as of end of period	(121,727)		(121,727)
Retained Earnings [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance as of beginning of period			604,884
Net income			166,390
Cash dividend declared ($1.26 per share)			(53,024)
Balance as of end of period	$ 718,250		$ 718,250