CONDENSED CONSOLIDATED STATEMENT OF STOCKHOLDERS' EQUITY (Unaudited) - 9 months ended Jun. 30, 2016 - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Paid-in-Capital	Treasury Stock	Retained Earnings	Accumulated Other Comprehensive Loss
Beginning Balance (in shares) at Sep. 30, 2015		31,290
Beginning Balance at Sep. 30, 2015	$ 436,998	$ 313	$ 1,152,789	$ (2,033,644)	$ 1,368,255	$ (50,715)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Share-based compensation	41,704		41,704
Issuance of treasury stock under employee stock plans (in shares)		689
Issuance of treasury stock under employee stock plans	(20,188)	$ 7	(44,794)	24,599
Tax effect from share-based payment arrangements	15,704		15,704
Repurchases of common stock (shares)		(1,027)
Repurchases of common stock	(100,472)	$ (10)		(100,462)
Dividends paid	(1,869)				(1,869)
Net income	77,344				77,344
Foreign currency translation adjustments	(21,180)					(21,180)
Ending Balance (in shares) at Jun. 30, 2016		30,952
Ending Balance at Jun. 30, 2016	$ 428,041	$ 310	$ 1,165,403	$ (2,109,507)	$ 1,443,730	$ (71,895)