Retirement Benefits (Schedule of Accumulated Benefit Obligations In Excess of and Less Than Fair Value of Plan Assets) (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Sep. 30, 2017
Plans with accumulated benefit obligation in excess of plan assets
Projected benefit obligation, plans with ABO in excess of plan assets	$ (65,938)	$ (82,447)
Accumulated benefit obligation, plans with ABO in excess of plan assets	(65,915)	(80,759)
Fair value of plan assets, plans with ABO in excess of plan assets	23,385	77,036
Plans with accumulated benefit obligation less than plan assets
Projected benefit obligation, plans with ABO less than plan assets	(187,579)	(145,052)
Accumulated benefit obligation, plans with ABO less than plan assets	(184,864)	(144,006)
Fair value of plan assets, plans with ABO less than plan assets	$ 204,337	$ 147,676