COMMON STOCK EQUITY (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance as of beginning of period (shares)			84,356,310
Balance as of beginning of period			$ 966,166
Net income	$ (7,460)	$ (14,274)	176,763	$ 166,390
Other comprehensive income	$ (318)	$ 834	364	$ 675
Common stock issued under stock plans			29,363
Tax benefits from stock plans			(1,386)
Cash dividend declared ($.68 per share)			(57,517)
Treasury stock and other			$ 9,559
Balance as of end of period (shares)	85,401,117		85,401,117
Balance as of end of period	$ 1,123,312		$ 1,123,312
Cash dividend declared per share (usd per share)	$ 0.23	$ 0.21	$ 0.68	$ 0.63
Common Stock [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance as of beginning of period (shares)			84,356,000
Balance as of beginning of period			$ 218,223
Common stock issued under stock plans (shares)			1,378,000
Common stock issued under stock plans			$ 2,607
Treasury stock and other (shares)			(333,000)
Balance as of end of period (shares)	85,401,000		85,401,000
Balance as of end of period	$ 220,830		$ 220,830
Premium on Common Stock [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance as of beginning of period			199,739
Common stock issued under stock plans			12,972
Tax benefits from stock plans			(1,386)
Balance as of end of period	211,325		211,325
Accumulated Other Comprehensive (Loss) Income [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance as of beginning of period			(5,594)
Other comprehensive income			364
Balance as of end of period	(5,230)		(5,230)
Treasury Stock And Other [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance as of beginning of period			(121,031)
Common stock issued under stock plans			13,784
Treasury stock and other			9,559
Balance as of end of period	(97,688)		(97,688)
Retained Earnings [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Balance as of beginning of period			674,829
Net income			176,763
Cash dividend declared ($.68 per share)			(57,517)
Balance as of end of period	$ 794,075		$ 794,075