Basis of Presentation and Summary of Significant Accounting Policies - Revenue Recognition (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2024	Mar. 31, 2023	Sep. 30, 2023
Disaggregation of Revenue [Line Items]
Total revenue	$ 541,540	$ 543,908	$ 928,358	$ 988,836
Customer deposits	28,716		28,716		$ 27,577
Contract with customer, liability, revenue recognized	10,100		21,900
Homebuilding revenue
Disaggregation of Revenue [Line Items]
Total revenue	538,636	542,007	919,555	986,091
Land sales and other revenue
Disaggregation of Revenue [Line Items]
Total revenue	$ 2,904	$ 1,901	$ 8,803	$ 2,745