Retirement Benefits (Schedule of Allocation of Plan Assets, Fair Value Hierarchy) (Details) - Defined Benefit Pension Plan [Member] - USD ($) $ in Thousands	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 291,107	$ 266,709	$ 234,133
United States [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	221,263	201,555	170,556
Foreign Plan
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	69,844	65,154	$ 63,577
Level 1 [Member] | United States [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	221,263	201,555
Level 1 [Member] | Foreign Plan
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	324	270
Level 2 [Member] | Foreign Plan
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	69,520	64,884
Cash and Cash Equivalents
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	3,832	1,385
Cash and Cash Equivalents | Level 1 [Member] | United States [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	3,508	1,115
Cash and Cash Equivalents | Level 1 [Member] | Foreign Plan
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	324	270
Debt Security, Corporate, US
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	149,727	70,492
Debt Security, Corporate, US | Level 1 [Member] | United States [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	149,727	70,492
Domestic Equity Large Cap Fund
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	41,988	65,025
Domestic Equity Large Cap Fund | Level 1 [Member] | United States [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	41,988	65,025
International Equity Large Cap Growth Fund
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	26,040	64,923
International Equity Large Cap Growth Fund | Level 1 [Member] | United States [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	26,040	64,923
Private Equity Funds Foreign Japan
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	2,610	2,470
Private Equity Funds Foreign Japan | Level 2 [Member] | Foreign Plan
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	2,610	2,470
Private Equity Funds Pooled Funds Foreign
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	2,180	2,135
Private Equity Funds Pooled Funds Foreign | Level 2 [Member] | Foreign Plan
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	2,180	2,135
Fixed Income Funds Japan
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	5,224	5,151
Fixed Income Funds Japan | Level 2 [Member] | Foreign Plan
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	5,224	5,151
Fixed Income Funds Foreign
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1,775	1,734
Fixed Income Funds Foreign | Level 2 [Member] | Foreign Plan
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1,775	1,734
Global Target Return Equity Bond Fund
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	15,201	13,002
Global Target Return Equity Bond Fund | Level 2 [Member] | Foreign Plan
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	15,201	13,002
United Kingdom Index Linked Equity Fund
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	3,236	2,878
United Kingdom Index Linked Equity Fund | Level 2 [Member] | Foreign Plan
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	3,236	2,878
Index linked international equity fund
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	6,093	5,351
Index linked international equity fund | Level 2 [Member] | Foreign Plan
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	6,093	5,351
Corporate Debt Securities United Kingdom
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	18,438	18,055
Corporate Debt Securities United Kingdom | Level 2 [Member] | Foreign Plan
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	18,438	18,055
Pooled funds: Index linked U.K. government securities fund [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	6,047	5,767
Pooled funds: Index linked U.K. government securities fund [Member] | Level 2 [Member] | Foreign Plan
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	6,047	5,767
Pooled funds: Index linked U.K. long-term government securities fund [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	8,716	8,341
Pooled funds: Index linked U.K. long-term government securities fund [Member] | Level 2 [Member] | Foreign Plan
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 8,716	$ 8,341