Basis of Presentation and Summary of Significant Accounting Policies - Revenue Recognition (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2022	Mar. 31, 2021	Sep. 30, 2021
Disaggregation of Revenue [Line Items]
Total revenue	$ 508,506	$ 549,889	$ 962,655	$ 978,428
Customer deposits	38,394		38,394		$ 28,526
Contract with customer, liability, revenue recognized	7,500		17,700
Homebuilding revenue
Disaggregation of Revenue [Line Items]
Total revenue	507,208	547,417	953,937	971,646
Land sales and other revenue
Disaggregation of Revenue [Line Items]
Total revenue	$ 1,298	$ 2,472	$ 8,718	$ 6,782