Retirement Benefits (Schedule of Net Periodic Benefit Costs) (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Defined Benefit Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 3,487	$ 2,767	$ 2,808
Interest cost	8,290	7,530	6,965
Expected return on plan assets	(14,624)	(14,394)	(13,134)
Amortization of: Net (gains) losses	900	889	2,368
Amortization of: Net prior service (benefit) cost	709	709	383
Net periodic (benefit) cost	(1,238)	(2,499)	(610)
Other Postretirement Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	5	7	14
Interest cost	1,154	1,165	1,244
Amortization of: Net (gains) losses	55	94	201
Amortization of: Net prior service (benefit) cost	(5)	(158)	(158)
Curtailment gain		(330)
Net periodic (benefit) cost	1,209	778	1,301
United States [Member] | Defined Benefit Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	1,451	1,643	1,675
Interest cost	6,384	6,004	5,757
Expected return on plan assets	(11,986)	(11,614)	(10,529)
Amortization of: Net (gains) losses	617	598	1,854
Amortization of: Net prior service (benefit) cost	709	709	383
Net periodic (benefit) cost	(2,825)	(2,660)	(860)
Other Countries [Member] | Defined Benefit Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	2,036	1,124	1,133
Interest cost	1,906	1,526	1,208
Expected return on plan assets	(2,638)	(2,780)	(2,605)
Amortization of: Net (gains) losses	283	291	514
Net periodic (benefit) cost	$ 1,587	$ 161	$ 250