Fair Value Measurements - Carrying Amount and Clarification of Assets and Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Sep. 30, 2017
Accounts, Notes, Loans and Financing Receivable [Line Items]
Discount on receivable	$ 9,200	$ 100
Notes receivable, net (including accreted deferred compensation of $9.2 million and $0.1 million as of September 30, 2018 and 2017, respectively)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Asset Recorded in Consolidated Balance Sheet	37,425	60,975
Maximum Exposure to Loss	$ 37,425	$ 60,975

Maximum potential amount of future payments (undiscounted) the guarantor could be required to make under the guarantee or each group of similar guarantees before reduction for potential recoveries under recourse or collateralization provisions.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 460
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (b)(1)
-URI http://asc.fasb.org/extlink&oid=115931803&loc=d3e12069-110248

Name:	us-gaap_GuaranteeObligationsMaximumExposure
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant