Inventory - Schedule of Interests in Lot Option Agreements (Details) - Unconsolidated Entities - USD ($) $ in Thousands	Mar. 31, 2026	Sep. 30, 2025
Real Estate Properties [Line Items]
Deposits and non-refundable pre-acquisition costs incurred	$ 373,439	$ 333,435
Remaining purchase price if lot option agreements are exercised	$ 1,639,210	$ 1,610,171