Retirement Benefits (Schedule of Net Periodic Benefit Costs) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2021	Mar. 31, 2020
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 1,168	$ 1,123	$ 2,329	$ 2,248
Interest cost	1,582	1,716	3,154	3,435
Expected return on plan assets	(4,161)	(3,794)	(8,299)	(7,713)
Amortization of: Net actuarial loss	369	617	732	1,236
Amortization of: Prior service cost	249	240	497	480
Net periodic retirement pension (benefit) cost	(793)	(98)	(1,587)	(314)
Contributions paid	675	601	1,218	1,732
Other Postretirement Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	1		1	1
Interest cost	149	196	299	391
Amortization of: Net actuarial loss	8	11	15	23
Amortization of: Prior service cost	1		1	1
Net periodic retirement pension (benefit) cost	159	207	316	416
Contributions paid - other postretirement plans	940	176	978	521
United States [Member] | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	432	415	864	830
Interest cost	1,239	1,397	2,478	2,795
Expected return on plan assets	(3,536)	(3,086)	(7,072)	(6,173)
Amortization of: Net actuarial loss	135	357	270	715
Amortization of: Prior service cost	243	234	485	468
Net periodic retirement pension (benefit) cost	(1,487)	(683)	(2,975)	(1,365)
Other Countries [Member] | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	736	708	1,465	1,418
Interest cost	343	319	676	640
Expected return on plan assets	(625)	(708)	(1,227)	(1,540)
Amortization of: Net actuarial loss	234	260	462	521
Amortization of: Prior service cost	6	6	12	12
Net periodic retirement pension (benefit) cost	694	585	1,388	1,051
Contributions paid	$ 675	$ 601	$ 1,218	$ 1,732