Inventory - Summary of Interests in Lot Option Agreements (Details) - Unconsolidated lot option agreements - USD ($) $ in Thousands	Sep. 30, 2016	Sep. 30, 2015
Real Estate Properties [Line Items]
Deposits & Non-refundable Preacquisition Costs Incurred	$ 80,433	$ 51,475
Remaining Obligation	$ 446,414	$ 420,070

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

Name:	us-gaap_RealEstatePropertiesLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration