Retirement Benefits (Schedule of Changes in Projected Benefit Obligations, Fair Value of Plan Assets, and Funded Status of Plan) (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Defined Benefit Pension Plan [Member]
Changes in projected benefit obligation:
Projected benefit obligation at beginning of year	$ 197,921	$ 299,364
Service cost	2,226	3,893	$ 4,651
Interest cost	10,434	6,893	6,318
Net actuarial gains	(9,388)	(84,607)
Contribution by participants	11	10
Benefits paid	(11,831)	(11,585)
Foreign currency exchange rate changes	5,112	(16,047)
Projected benefit obligation at end of year	194,485	197,921	299,364
Changes in fair value of plan assets:
Fair value of plan assets at beginning of year	202,060	291,107
Actual return on plan assets	9,928	(68,506)
Contributions by the Company	2,322	2,370
Contribution by participants	11	10
Benefits paid	(11,831)	(11,585)
Foreign currency exchange rate changes	3,655	(11,336)
Fair value of plan assets at end of year	206,145	202,060	291,107
Net over/(under) funded status at end of year	11,660	4,139
Other Postretirement Benefits Plan [Member]
Changes in projected benefit obligation:
Projected benefit obligation at beginning of year	16,797	21,544
Service cost	1	1	1
Interest cost	904	577	599
Net actuarial gains	(682)	(3,504)
Contribution by participants	873	923
Benefits paid	(2,557)	(2,744)
Projected benefit obligation at end of year	15,336	16,797	21,544
Changes in fair value of plan assets:
Contributions by the Company	1,684	1,821
Contribution by participants	873	923
Benefits paid	(2,557)	(2,744)
Net over/(under) funded status at end of year	(15,336)	(16,797)
United States [Member] | Defined Benefit Pension Plan [Member]
Changes in projected benefit obligation:
Projected benefit obligation at beginning of year	132,444	177,346
Service cost	893	1,554	1,729
Interest cost	7,297	5,281	4,957
Net actuarial gains	(4,946)	(43,639)
Benefits paid	(8,466)	(8,098)
Projected benefit obligation at end of year	127,222	132,444	177,346
Changes in fair value of plan assets:
Fair value of plan assets at beginning of year	154,481	221,263
Actual return on plan assets	9,355	(58,684)
Benefits paid	(8,466)	(8,098)
Fair value of plan assets at end of year	155,370	154,481	221,263
Net over/(under) funded status at end of year	28,148	22,037
Foreign Plan | Defined Benefit Pension Plan [Member]
Changes in projected benefit obligation:
Projected benefit obligation at beginning of year	65,477	122,018
Service cost	1,333	2,339	2,922
Interest cost	3,137	1,612	1,361
Net actuarial gains	(4,442)	(40,968)
Contribution by participants	11	10
Benefits paid	(3,365)	(3,487)
Foreign currency exchange rate changes	5,112	(16,047)
Projected benefit obligation at end of year	67,263	65,477	122,018
Changes in fair value of plan assets:
Fair value of plan assets at beginning of year	47,579	69,844
Actual return on plan assets	573	(9,822)
Contributions by the Company	2,322	2,370
Contribution by participants	11	10
Benefits paid	(3,365)	(3,487)
Foreign currency exchange rate changes	3,655	(11,336)
Fair value of plan assets at end of year	50,775	47,579	$ 69,844
Net over/(under) funded status at end of year	$ (16,488)	$ (17,898)