Retirement Benefits (Schedule of Amounts Recognized in Balance Sheet and Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Defined Benefit Pension Plan [Member]
Amounts recognized in statement of financial position consist of:
Other non-current assets	$ 46,099	$ 20,540
Accrued liabilities	(1,017)	(1,059)
Other non-current liabilities	(53,339)	(60,395)
Net over/(under) funded status at end of year	(8,257)	(40,914)
Amounts recognized in accumulated other comprehensive income consist of:
Unrecognized net prior service cost (benefit)	5,039	5,397
Unrecognized net (gains) losses	14,044	40,111
Total amounts recognized	19,083	45,508	$ 67,137
Deferred taxes	(9,476)	(16,178)
Amounts recognized in accumulated other comprehensive income	9,607	29,330
Other Postretirement Benefit Plans [Member]
Amounts recognized in statement of financial position consist of:
Accrued liabilities	(1,808)	(1,992)
Other non-current liabilities	(19,736)	(23,453)
Net over/(under) funded status at end of year	(21,544)	(25,445)
Amounts recognized in accumulated other comprehensive income consist of:
Unrecognized net prior service cost (benefit)		1
Unrecognized net (gains) losses	(2,815)	(363)
Total amounts recognized	(2,815)	(362)	1
Deferred taxes	289	(324)
Amounts recognized in accumulated other comprehensive income	(2,526)	(686)
United States [Member] | Defined Benefit Pension Plan [Member]
Amounts recognized in statement of financial position consist of:
Other non-current assets	43,917	19,064
Other non-current liabilities		(1,586)
Net over/(under) funded status at end of year	43,917	17,478
Amounts recognized in accumulated other comprehensive income consist of:
Unrecognized net prior service cost (benefit)	4,455	4,814
Unrecognized net (gains) losses	(10,816)	9,317
Total amounts recognized	(6,361)	14,131	33,917
Deferred taxes	(1,691)	(6,721)
Amounts recognized in accumulated other comprehensive income	(8,052)	7,410
Foreign Plan | Defined Benefit Pension Plan [Member]
Amounts recognized in statement of financial position consist of:
Other non-current assets	2,182	1,476
Accrued liabilities	(1,017)	(1,059)
Other non-current liabilities	(53,339)	(58,809)
Net over/(under) funded status at end of year	(52,174)	(58,392)
Amounts recognized in accumulated other comprehensive income consist of:
Unrecognized net prior service cost (benefit)	584	583
Unrecognized net (gains) losses	24,860	30,794
Total amounts recognized	25,444	31,377	$ 33,220
Deferred taxes	(7,785)	(9,457)
Amounts recognized in accumulated other comprehensive income	$ 17,659	$ 21,920