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, 2021	Sep. 30, 2020	Sep. 30, 2019
Defined Benefit Pension Plan [Member]
Changes in projected benefit obligation:
Projected benefit obligation at beginning of year	$ 307,623	$ 297,130
Plan amendment	611
Service cost	4,651	4,524	$ 3,487
Interest cost	6,318	6,868	8,290
Net actuarial losses (gains)	(9,955)	2,970
Contribution by participants	10	100
Benefits paid	(11,314)	(10,103)
Settlements		(476)
Foreign currency exchange rate changes	1,420	6,610
Projected benefit obligation at end of year	299,364	307,623	297,130
Changes in fair value of plan assets:
Fair value of plan assets at beginning of year	266,709	234,133
Actual return on plan assets	31,915	38,153
Contributions by the Company	2,185	2,272
Contribution by participants	10	100
Benefits paid	(11,314)	(10,103)
Settlements		(476)
Foreign currency exchange rate changes	1,602	2,630
Fair value of plan assets at end of year	291,107	266,709	234,133
Net over/(under) funded status at end of year	(8,257)	(40,914)
United States [Member] | Defined Benefit Pension Plan [Member]
Changes in projected benefit obligation:
Projected benefit obligation at beginning of year	184,077	175,595
Plan amendment	611
Service cost	1,729	1,659	1,451
Interest cost	4,957	5,590	6,384
Net actuarial losses (gains)	(6,496)	7,811
Contribution by participants		91
Benefits paid	(7,532)	(6,669)
Projected benefit obligation at end of year	177,346	184,077	175,595
Changes in fair value of plan assets:
Fair value of plan assets at beginning of year	201,555	170,556
Actual return on plan assets	27,240	37,577
Contribution by participants		91
Benefits paid	(7,532)	(6,669)
Fair value of plan assets at end of year	221,263	201,555	170,556
Net over/(under) funded status at end of year	43,917	17,478
Foreign Plan | Defined Benefit Pension Plan [Member]
Changes in projected benefit obligation:
Projected benefit obligation at beginning of year	123,546	121,535
Service cost	2,922	2,865	2,036
Interest cost	1,361	1,278	1,906
Net actuarial losses (gains)	(3,459)	(4,841)
Contribution by participants	10	9
Benefits paid	(3,782)	(3,434)
Settlements		(476)
Foreign currency exchange rate changes	1,420	6,610
Projected benefit obligation at end of year	122,018	123,546	121,535
Changes in fair value of plan assets:
Fair value of plan assets at beginning of year	65,154	63,577
Actual return on plan assets	4,675	576
Contributions by the Company	2,185	2,272
Contribution by participants	10	9
Benefits paid	(3,782)	(3,434)
Settlements		(476)
Foreign currency exchange rate changes	1,602	2,630
Fair value of plan assets at end of year	69,844	65,154	63,577
Net over/(under) funded status at end of year	(52,174)	(58,392)
Other Postretirement Benefit Plans [Member]
Changes in projected benefit obligation:
Projected benefit obligation at beginning of year	25,445	26,671
Service cost	1	2
Interest cost	599	782
Net actuarial losses (gains)	(2,422)	(313)
Contribution by participants	993	1,088
Benefits paid	(3,072)	(2,785)
Projected benefit obligation at end of year	21,544	25,445	$ 26,671
Changes in fair value of plan assets:
Contributions by the Company	2,079	1,697
Contribution by participants	993	1,088
Benefits paid	(3,072)	(2,785)
Net over/(under) funded status at end of year	$ (21,544)	$ (25,445)