Retirement Benefits (Schedule of Amounts Recognized in Balance Sheet and Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Defined Benefit Pension Plan [Member]
Amounts recognized in statement of financial position consist of:
Other non-current assets	$ 838	$ 18,158
Accrued liabilities	(1,539)	(1,322)
Other non-current liabilities	(62,295)	(42,631)
Net (under)/over funded status at end of year	(62,996)	(25,795)
Amounts recognized in accumulated other comprehensive loss (income) consist of:
Unrecognized net prior service (benefit) cost	6,329	6,459
Unrecognized net (gains) losses	60,808	18,814
Total amounts recognized	67,137	25,273	$ 38,390
Deferred taxes	(21,606)	(10,973)
Amounts recognized in accumulated other comprehensive loss (income)	45,531	14,300
Other Postretirement Benefit Plans [Member]
Amounts recognized in statement of financial position consist of:
Accrued liabilities	(2,048)	(2,249)
Other non-current liabilities	(24,623)	(25,736)
Net (under)/over funded status at end of year	(26,671)	(27,985)
Amounts recognized in accumulated other comprehensive loss (income) consist of:
Unrecognized net prior service (benefit) cost	4	(1)
Unrecognized net (gains) losses	(3)	425
Total amounts recognized	1	424	3,074
Deferred taxes	(414)	(518)
Amounts recognized in accumulated other comprehensive loss (income)	(413)	(94)
United States [Member] | Defined Benefit Pension Plan [Member]
Amounts recognized in statement of financial position consist of:
Other non-current assets		17,068
Other non-current liabilities	(5,039)	(1,758)
Net (under)/over funded status at end of year	(5,039)	15,310
Amounts recognized in accumulated other comprehensive loss (income) consist of:
Unrecognized net prior service (benefit) cost	5,750	6,459
Unrecognized net (gains) losses	28,167	4,285
Total amounts recognized	33,917	10,744	24,192
Deferred taxes	(11,577)	(5,892)
Amounts recognized in accumulated other comprehensive loss (income)	22,340	4,852
Other Countries [Member] | Defined Benefit Pension Plan [Member]
Amounts recognized in statement of financial position consist of:
Other non-current assets	838	1,090
Accrued liabilities	(1,539)	(1,322)
Other non-current liabilities	(57,256)	(40,873)
Net (under)/over funded status at end of year	(57,957)	(41,105)
Amounts recognized in accumulated other comprehensive loss (income) consist of:
Unrecognized net prior service (benefit) cost	579
Unrecognized net (gains) losses	32,641	14,529
Total amounts recognized	33,220	14,529	$ 14,198
Deferred taxes	(10,029)	(5,081)
Amounts recognized in accumulated other comprehensive loss (income)	$ 23,191	$ 9,448