Retirement Benefits (Narrative) (Details) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2020	Mar. 31, 2019	Sep. 30, 2019
Defined Benefit Plan Disclosure [Line Items]
Percentage of annual contribution equal to eligible prior year wages			5.00%
Common shares issued from treasury stock for benefit plans, shares	124	158
Common shares issued from treasury stock for benefit plans	$ 14,748	$ 14,846	$ 14,748	$ 14,846
Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Number of years of service			2 years
Treasury Stock at Cost [Member]
Defined Benefit Plan Disclosure [Line Items]
Common shares issued from treasury stock for benefit plans, shares	124	158	124	158
Common shares issued from treasury stock for benefit plans	$ 5,328	$ 5,673	$ 5,328	$ 5,673
Defined Benefit Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
UK High Court Ruling Amendment					$ 601