Derivative Instruments and Hedging Activities (Impact of Derivative Instruments on Earnings) (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Derivative Instruments, Gain (Loss) [Line Items]
Amount of (Income) Expense Recognized in Earnings on Derivative	$ 1,467	$ (72)	$ 21
Amount of Gain/Loss Recognized in Accumulated OCI on Derivative	23,000
Amount of (Gain) Loss Reclassified from Accumulated OCI into Earnings	1,467	(72)	21
Fixed-Rate Cross Currency Interest Rate Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of (Income) Expense Recognized in Earnings on Derivative	1,067
Amount of Gain/Loss Recognized in Accumulated OCI on Derivative	21,966
Amount of (Gain) Loss Reclassified from Accumulated OCI into Earnings	1,067
Floating-Rate Cross Currency Interest Rate Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of (Income) Expense Recognized in Earnings on Derivative	472
Amount of Gain/Loss Recognized in Accumulated OCI on Derivative	1,034
Amount of (Gain) Loss Reclassified from Accumulated OCI into Earnings	472
Treasury Lock [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of (Income) Expense Recognized in Earnings on Derivative	(72)	(72)	21
Amount of (Gain) Loss Reclassified from Accumulated OCI into Earnings	$ (72)	$ (72)	$ 21