Retirement Benefits (Schedule of Net Periodic Benefit Costs) (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Defined Benefit Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 2,767	$ 2,808	$ 2,444
Interest cost	7,530	6,965	6,873
Expected return on plan assets	(14,394)	(13,134)	(12,799)
Amortization of: Net (gains) losses	889	2,368	1,538
Amortization of: Prior service (benefit) cost	709	383	384
Settlement loss			47
Net periodic benefit cost	(2,499)	(610)	(1,513)
Other Postretirement Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	7	14	22
Interest cost	1,165	1,244	1,048
Amortization of: Net (gains) losses	94	201	156
Amortization of: Prior service (benefit) cost	(158)	(158)	(158)
Curtailment (gain) loss	(330)
Net periodic benefit cost	778	1,301	1,068
UNITED STATES | Defined Benefit Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	1,643	1,675	1,695
Interest cost	6,004	5,757	5,236
Expected return on plan assets	(11,614)	(10,529)	(10,140)
Amortization of: Net (gains) losses	598	1,854	1,292
Amortization of: Prior service (benefit) cost	709	383	384
Settlement loss			47
Net periodic benefit cost	(2,660)	(860)	(1,486)
Foreign Plan [Member] | Defined Benefit Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	1,124	1,133	749
Interest cost	1,526	1,208	1,637
Expected return on plan assets	(2,780)	(2,605)	(2,659)
Amortization of: Net (gains) losses	291	514	246
Net periodic benefit cost	$ 161	$ 250	$ (27)