Credit Facilities and Short-term Borrowings (Short-term Borrowings and Availability Under Various Short-term Credit Facilities) (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Sep. 30, 2016
Line of Credit Facility [Line Items]
Total availability	$ 1,017,588
Outstanding letters of credit and guarantees	(10,972)
Outstanding borrowings	(32,600)
Remaining availability	974,016
Foreign Performance Guarantee Facilities [Member]
Line of Credit Facility [Line Items]
Total availability	10,058
Outstanding letters of credit and guarantees	(351)
Outstanding borrowings	0
Remaining availability	9,707
Foreign Lines of Credit And Overdraft Facilities [Member]
Line of Credit Facility [Line Items]
Total availability	7,530
Outstanding letters of credit and guarantees	0
Outstanding borrowings	0
Remaining availability	7,530
Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Total availability	1,000,000
Outstanding letters of credit and guarantees	(10,621)
Outstanding borrowings	(32,600)	$ (156,700)
Remaining availability	$ 956,779