Retirement Benefits (Narrative) (Details) $ in Thousands	12 Months Ended
Sep. 30, 2019 USD ($)
Defined Benefit Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
UK High Court Ruling Amendment	$ 601

Amount of increase (decrease) in benefit obligation of defined benefit plan from change in terms of existing plan or initiation of new plan.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (a)(7)
-URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920

Name:	us-gaap_DefinedBenefitPlanPlanAmendments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration