Retirement Benefits (Schedule of Changes in Plan Assets and Benefit Obligations Recorded in Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Defined Benefit Plan Disclosure [Line Items]
Net (gain) loss	$ (27,809)	$ (20,179)	$ 43,817
Prior service cost due to plan amendment	(611)		(601)
Amortization of: Net losses	1,502	2,523	955
Prior service (cost) benefit	(995)	(962)	(704)
Foreign currency exchange rate changes	855	1,672	(1,318)
Defined Benefit Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Accumulated other comprehensive losses at beginning of year	45,508	67,137
Net (gain) loss	(25,425)	(19,866)
Prior service cost due to plan amendment	611
Amortization of: Net losses	(1,472)	(2,476)
Prior service (cost) benefit	(994)	(959)
Foreign currency exchange rate changes	855	1,672
Accumulated other comprehensive losses at end of year	19,083	45,508	67,137
Defined Benefit Pension Plan [Member] | United States [Member]
Defined Benefit Plan Disclosure [Line Items]
Accumulated other comprehensive losses at beginning of year	14,131	33,917
Net (gain) loss	(19,593)	(17,420)
Prior service cost due to plan amendment	611
Amortization of: Net losses	(541)	(1,430)
Prior service (cost) benefit	(969)	(936)
Accumulated other comprehensive losses at end of year	(6,361)	14,131	33,917
Defined Benefit Pension Plan [Member] | Foreign Plan
Defined Benefit Plan Disclosure [Line Items]
Accumulated other comprehensive losses at beginning of year	31,377	33,220
Net (gain) loss	(5,832)	(2,446)
Amortization of: Net losses	(931)	(1,046)
Prior service (cost) benefit	(25)	(23)
Foreign currency exchange rate changes	855	1,672
Accumulated other comprehensive losses at end of year	25,444	31,377	33,220
Other Postretirement Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Accumulated other comprehensive losses at beginning of year	(362)	1
Net (gain) loss	(2,422)	(313)
Amortization of: Net losses	(30)	(47)
Prior service (cost) benefit	(1)	(3)
Accumulated other comprehensive losses at end of year	$ (2,815)	$ (362)	$ 1