CONDENSED CONSOLIDATED STATEMENT OF STOCKHOLDERS' EQUITY (USD $) In Thousands, unless otherwise specified	Total	Common Stock	Paid-in-Capital	Treasury Stock	Retained Earnings	Accumulated Other Comprehensive Loss
Beginning Balance at Sep. 30, 2014	$ 454,614	$ 320	$ 1,129,317	$ (1,936,095)	$ 1,284,261	$ (23,189)
Beginning Balance (in shares) at Sep. 30, 2014		32,047
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Share-based compensation	8,794		8,794
Issuance of treasury stock under employee stock plans	(8,294)	5	(26,205)	17,906
Issuance of treasury stock under employee stock plans (in shares)		521
Tax effect from share-based payment arrangements	6,379		6,379
Repurchases of common stock	(60,593)	(8)		(60,585)
Repurchases of common stock (shares)		(844)
Dividends paid	(635)				(635)
Net income	14,407				14,407
Foreign currency translation adjustments	(11,451)					(11,451)
Ending Balance at Dec. 31, 2014	$ 403,221	$ 317	$ 1,118,285	$ (1,978,774)	$ 1,298,033	$ (34,640)
Ending Balance (in shares) at Dec. 31, 2014		31,724