Retirement Benefits (Schedule of Net Periodic Benefit Costs) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Mar. 31, 2018	Mar. 31, 2017
Other Postretirement Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 2	$ 3	$ 4	$ 7
Interest cost	291	311	583	622
Amortization of: Net (gains) losses	24	51	48	101
Amortization of: Prior service (benefit) cost	(39)	(39)	(79)	(79)
Curtailment (gain) loss			(330)
Net periodic retirement (benefit) cost	278	326	226	651
Contributions paid - other postretirement plans	1,009	804	1,235	1,419
Defined Benefit Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	576	605	1,145	1,216
Interest cost	1,845	1,735	3,675	3,470
Expected return on plan assets	(3,620)	(3,271)	(7,210)	(6,544)
Amortization of: Net (gains) losses	224	589	446	1,180
Amortization of: Prior service (benefit) cost	178	96	355	192
Net periodic retirement (benefit) cost	(797)	(246)	(1,589)	(486)
Contributions paid - pensions	119	101	431	466
Defined Benefit Pension Plan [Member] | UNITED STATES
Defined Benefit Plan Disclosure [Line Items]
Service cost	411	418	822	837
Interest cost	1,501	1,439	3,002	2,878
Expected return on plan assets	(2,903)	(2,633)	(5,807)	(5,265)
Amortization of: Net (gains) losses	149	463	299	927
Amortization of: Prior service (benefit) cost	178	96	355	192
Net periodic retirement (benefit) cost	(664)	(217)	(1,329)	(431)
Contributions paid - pensions	0	0	0	0
Defined Benefit Pension Plan [Member] | Foreign Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	165	187	323	379
Interest cost	344	296	673	592
Expected return on plan assets	(717)	(638)	(1,403)	(1,279)
Amortization of: Net (gains) losses	75	126	147	253
Amortization of: Prior service (benefit) cost	0	0	0	0
Net periodic retirement (benefit) cost	(133)	(29)	(260)	(55)
Contributions paid - pensions	$ 119	$ 101	$ 431	$ 466