Retirement Benefits (Schedule of Changes in accumulated other comprehensive losses for the defined benefit plans) (Details) - USD ($) $ in Thousands	12 Months Ended
Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Defined Benefit Plan Disclosure [Line Items]
Net (gain) loss arising during the period	$ (13,805)	$ (22,979)	$ 19,718
Loss (gain) due to settlement or curtailment arising during the period	(59)		(47)
Amortization of: Net gains (losses)	(985)	(2,570)	(1,694)
Amortization of: Prior service benefit (cost)	(551)	3,470	(226)
Foreign currency exchange rate changes	(367)	43	(2,239)
Defined Benefit Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Accumulated other comprehensive loss (earnings), beginning of year	38,390	58,334
Net (gain) loss arising during the period	(11,151)	(20,930)
Amortization of: Net gains (losses)	(890)	(2,369)
Amortization of: Prior service benefit (cost)	(709)	3,312
Foreign currency exchange rate changes	(367)	43
Accumulated other comprehensive loss (earning), end of year	25,273	38,390	58,334
Other Postretirement Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Accumulated other comprehensive loss (earnings), beginning of year	3,074	5,166
Net (gain) loss arising during the period	(2,654)	(2,049)
Loss (gain) due to settlement or curtailment arising during the period	(59)
Amortization of: Net gains (losses)	(95)	(201)
Amortization of: Prior service benefit (cost)	158	158
Accumulated other comprehensive loss (earning), end of year	424	3,074	5,166
UNITED STATES \| Defined Benefit Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Accumulated other comprehensive loss (earnings), beginning of year	24,192	37,539
Net (gain) loss arising during the period	(12,141)	(14,805)
Amortization of: Net gains (losses)	(598)	(1,854)
Amortization of: Prior service benefit (cost)	(709)	3,312
Accumulated other comprehensive loss (earning), end of year	10,744	24,192	37,539
Foreign Plan [Member] \| Defined Benefit Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Accumulated other comprehensive loss (earnings), beginning of year	14,198	20,795
Net (gain) loss arising during the period	990	(6,125)
Amortization of: Net gains (losses)	(292)	(515)
Foreign currency exchange rate changes	(367)	43
Accumulated other comprehensive loss (earning), end of year	$ 14,529	$ 14,198	$ 20,795

Amount, before tax, of accumulated other comprehensive (income) loss for defined benefit plan, that has not been recognized in net periodic benefit cost (credit).

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Amount, before tax, of reclassification adjustment from accumulated other comprehensive (income) loss for prior service cost (credit) of defined benefit plan.

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Amount, before tax, of increase (decrease) to other comprehensive income from settlement and curtailment gain (loss) of defined benefit plan.

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Amount, before tax, of gain (loss) for (increase) decrease in value of benefit obligation for change in actuarial assumptions and increase (decrease) in value of plan assets from experience different from that assumed of defined benefit plan, that has not been recognized in net periodic benefit (cost) credit.

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Amount, before tax, of reclassification adjustment from accumulated other comprehensive income (loss) for gain (loss) of defined benefit plan.

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The amount of increase or decrease in amounts recognized in other comprehensive income (but not yet recognized in net periodic benefit cost) for defined benefit plans attributed to foreign currency changes. The effects of foreign currency exchange rate changes that are to be disclosed are those applicable to plans of a foreign operation whose functional currency is not the reporting currency.

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