Basis of Presentation and Summary of Significant Accounting Policies - Summary of Interests in Lot Option Agreements (Details) - Unconsolidated lot option agreements - USD ($) $ in Thousands	Sep. 30, 2021	Sep. 30, 2020
Real Estate Properties [Line Items]
Deposits & Non-refundable Pre-acquisition Costs Incurred	$ 114,688	$ 75,921
Remaining Obligation, Net of Cash Deposits	$ 676,149	$ 395,133

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.

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