Basis of Presentation and Summary of Significant Accounting Policies - Revenue Recognition (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Sep. 30, 2021
Disaggregation of Revenue [Line Items]
Total revenue	$ 454,149	$ 428,539
Customer deposits	31,321		$ 28,526
Contract with customer, liability, revenue recognized	10,200
Homebuilding revenue
Disaggregation of Revenue [Line Items]
Total revenue	446,729	424,229
Land sales and other revenue
Disaggregation of Revenue [Line Items]
Total revenue	$ 7,420	$ 4,310