Basis of Presentation and Summary of Significant Accounting Policies - Schedule of Revenue Recognition (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2023
Summary of Significant Accounting Policies [Line Items]
Total revenue	$ 2,371,555	$ 2,330,197	$ 2,206,785
Homebuilding revenue
Summary of Significant Accounting Policies [Line Items]
Total revenue	2,302,630	2,292,984	2,198,400
Land sales and other revenue
Summary of Significant Accounting Policies [Line Items]
Total revenue	$ 68,925	$ 37,213	$ 8,385