Stock-based Compensation (Narrative) (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Sep. 30, 2017
Stock-based Compensation Narrative
Total unrecognized compensation expense related to stock awards	$ 79,121	$ 63,323

Unrecognized cost of unvested share-based compensation awards.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (i)
-URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant