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, 2019	Sep. 30, 2018	Sep. 30, 2017
Defined Benefit Plan Disclosure [Line Items]
Net gain	$ 43,817	$ (13,805)	$ (22,979)
Prior service cost due to plan amendment	601
Loss due to settlement or curtailment arising during the period		(59)
Amortization of: Net losses	(955)	(985)	(2,570)
Prior service (cost) benefit	(704)	(551)	3,470
Foreign currency exchange rate changes	(1,318)	(367)	43
Defined Benefit Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Accumulated other comprehensive losses at beginning of year	25,273	38,390
Net gain	44,190	(11,151)
Prior service cost due to plan amendment	601
Amortization of: Net losses	(900)	(890)
Prior service (cost) benefit	(709)	(709)
Foreign currency exchange rate changes	(1,318)	(367)
Accumulated other comprehensive losses at end of year	67,137	25,273	38,390
Other Postretirement Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Accumulated other comprehensive losses at beginning of year	424	3,074
Net gain	(373)	(2,654)
Loss due to settlement or curtailment arising during the period		(59)
Amortization of: Net losses	(55)	(95)
Prior service (cost) benefit	5	158
Accumulated other comprehensive losses at end of year	1	424	3,074
United States [Member] \| Defined Benefit Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Accumulated other comprehensive losses at beginning of year	10,744	24,192
Net gain	24,499	(12,141)
Prior service cost due to plan amendment
Amortization of: Net losses	(617)	(598)
Prior service (cost) benefit	(709)	(709)
Foreign currency exchange rate changes
Accumulated other comprehensive losses at end of year	33,917	10,744	24,192
Other Countries [Member] \| Defined Benefit Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Accumulated other comprehensive losses at beginning of year	14,529	14,198
Net gain	19,691	990
Prior service cost due to plan amendment	601
Amortization of: Net losses	(283)	(292)
Prior service (cost) benefit
Foreign currency exchange rate changes	(1,318)	(367)
Accumulated other comprehensive losses at end of year	$ 33,220	$ 14,529	$ 14,198

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