Basis of Presentation and Summary of Significant Accounting Policies - Revenue Recognition (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022
Summary of Significant Accounting Policies [Line Items]
Total revenue	$ 2,330,197	$ 2,206,785	$ 2,316,988
Homebuilding revenue
Summary of Significant Accounting Policies [Line Items]
Total revenue	2,292,984	2,198,400	2,302,520
Land sales and other revenue
Summary of Significant Accounting Policies [Line Items]
Total revenue	$ 37,213	$ 8,385	$ 14,468