Restructuring Charges (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015
Restructuring Reserve [Roll Forward]
Balance, beginning of period	$ 36,608	$ 15,254	$ 26,370
Restructuring charges	7,942	76,273	43,409
Cash disbursements	(37,074)	(55,019)	(53,588)
Restructuring Reserve, Settled without Cash	(704)
Foreign currency impact	(528)	100	(937)
Balance, end of period	6,244	36,608	15,254
Employee Severance And Related Benefits
Restructuring Reserve [Roll Forward]
Balance, beginning of period	35,177	14,086	25,835
Restructuring charges	2,373	74,929	41,997
Cash disbursements	(35,069)	(53,966)	(52,882)
Restructuring Reserve, Settled without Cash	0
Foreign currency impact	(745)	128	(864)
Balance, end of period	1,736	35,177	14,086
Facility Closures and Other Costs
Restructuring Reserve [Roll Forward]
Balance, beginning of period	1,431	1,168	535
Restructuring charges	5,569	1,344	1,412
Cash disbursements	(2,005)	(1,053)	(706)
Restructuring Reserve, Settled without Cash	(704)
Foreign currency impact	217	(28)	(73)
Balance, end of period	$ 4,508	$ 1,431	$ 1,168