Inventories - Narrative (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Sep. 30, 2017
Inventory [Line Items]
Customer deposits	$ 104,914	$ 107,837
Inventory
Inventory [Line Items]
Customer deposits	$ 102,200	$ 106,200

The current portion of money or property received from customers which is either to be returned upon satisfactory contract completion or applied to customer receivables in accordance with the terms of the contract or the understandings.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.20)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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