Basis of Presentation and Summary of Significant Accounting Policies - Revenue Recognition (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Sep. 30, 2019
Disaggregation of Revenue [Line Items]
Total revenue	$ 417,804	$ 402,040
Customer deposits	13,910		$ 11,539
Contract with customer, liability, revenue recognized	6,100
Refunded by buyer	200
Contract with customer, liability, remaining liability	5,200
Homebuilding revenue
Disaggregation of Revenue [Line Items]
Total revenue	417,399	400,982
Land sales and other revenue
Disaggregation of Revenue [Line Items]
Total revenue	$ 405	$ 1,058