Consolidated Statements Of Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Deficit [Member]	Accumulated Other Comprehensive Loss [Member]
Beginning Balance, shares at Sep. 30, 2013		118,446
Beginning Balance, value at Sep. 30, 2013	$ 926,480	$ 1,185	$ 1,786,820	$ (810,365)	$ (51,160)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued for employee stock-based awards, shares		2,455
Common stock issued for employee stock-based awards, value	877	$ 24	853
Shares surrendered by employees to pay taxes related to stock-based awards, shares		(808)
Shares surrendered by employees to pay taxes related to stock-based awards, value	(26,857)	$ (8)	(26,849)
Compensation expense from stock-based awards	50,889		50,889
Excess tax benefits (tax shortfalls) from stock-based awards	10,428		10,428
Net income	$ 160,194			160,194
Repurchases of common stock, shares	(5,100)	(5,068)
Repurchases of common stock, value	$ (187,415)	$ (51)	(187,364)
Common stock repurchase holdback	(37,500)		(37,500)
Unrealized loss on hedging instruments, net of tax	0
Foreign currency translation adjustment	(24,069)				(24,069)
Unrealized loss on available-for-sale securities, net of tax	0
Change in pension benefits, net of tax	(19,138)				(19,138)
Ending Balance, shares at Sep. 30, 2014		115,025
Ending Balance, value at Sep. 30, 2014	853,889	$ 1,150	1,597,277	(650,171)	(94,367)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued for employee stock-based awards, shares		2,212
Common stock issued for employee stock-based awards, value	41	$ 22	19
Shares surrendered by employees to pay taxes related to stock-based awards, shares		(764)
Shares surrendered by employees to pay taxes related to stock-based awards, value	(29,207)	$ (8)	(29,199)
Compensation expense from stock-based awards	50,182		50,182
Excess tax benefits (tax shortfalls) from stock-based awards	24		24
Net income	$ 47,557			47,557
Repurchases of common stock, shares	(2,700)	(2,728)
Repurchases of common stock, value	$ (64,940)	$ (27)	(64,913)
Unrealized loss on hedging instruments, net of tax	0
Foreign currency translation adjustment	(47,177)				(47,177)
Unrealized loss on available-for-sale securities, net of tax	0
Change in pension benefits, net of tax	$ 49,802				49,802
Ending Balance, shares at Sep. 30, 2015	113,745	113,745
Ending Balance, value at Sep. 30, 2015	$ 860,171	$ 1,137	1,553,390	(602,614)	(91,742)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued for employee stock-based awards, shares		1,820
Common stock issued for employee stock-based awards, value	21	$ 18	3
Shares surrendered by employees to pay taxes related to stock-based awards, shares		(597)
Shares surrendered by employees to pay taxes related to stock-based awards, value	(20,939)	$ (5)	(20,934)
Compensation expense from stock-based awards	65,996		65,996
Excess tax benefits (tax shortfalls) from stock-based awards	93		93
Net income	(54,465)			(54,465)
Unrealized loss on hedging instruments, net of tax	(1,244)				(1,244)
Foreign currency translation adjustment	408				408
Unrealized loss on available-for-sale securities, net of tax	(122)				(122)
Change in pension benefits, net of tax	$ (7,253)				(7,253)
Ending Balance, shares at Sep. 30, 2016	114,968	114,968
Ending Balance, value at Sep. 30, 2016	$ 842,666	$ 1,150	$ 1,598,548	$ (657,079)	$ (99,953)