Retirement Benefits (Schedule of Net Periodic Benefit Costs) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2020	Mar. 31, 2019
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 1,123	$ 874	$ 2,248	$ 1,749
Interest cost	1,716	2,081	3,435	4,157
Expected return on plan assets	(3,794)	(3,669)	(7,713)	(7,327)
Amortization of: Net actuarial loss	617	228	1,236	453
Amortization of: Prior service cost (benefit)	240	178	480	355
Net periodic retirement pension (benefit) cost	(98)	(308)	(314)	(613)
Contributions paid	601	509	1,732	1,063
Other Postretirement Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost		2	1	3
Interest cost	196	289	391	577
Amortization of: Net actuarial loss	11	14	23	28
Amortization of: Prior service cost (benefit)		(2)	1	(3)
Net periodic retirement pension (benefit) cost	207	303	416	605
Contributions paid - other postretirement plans	176	704	521	1,077
United States [Member] | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	415	362	830	725
Interest cost	1,397	1,596	2,795	3,192
Expected return on plan assets	(3,086)	(2,997)	(6,173)	(5,993)
Amortization of: Net actuarial loss	357	155	715	309
Amortization of: Prior service cost (benefit)	234	178	468	355
Net periodic retirement pension (benefit) cost	(683)	(706)	(1,365)	(1,412)
Other Countries [Member] | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	708	512	1,418	1,024
Interest cost	319	485	640	965
Expected return on plan assets	(708)	(672)	(1,540)	(1,334)
Amortization of: Net actuarial loss	260	73	521	144
Amortization of: Prior service cost (benefit)	6		12
Net periodic retirement pension (benefit) cost	585	398	1,051	799
Contributions paid	$ 601	$ 509	$ 1,732	$ 1,063