Basis of Presentation and Summary of Significant Accounting Policies - Revenue Recognition (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Sep. 30, 2018
Disaggregation of Revenue [Line Items]
Total revenue	$ 402,040	$ 372,489
Customer deposits	13,462		$ 14,903
Contract with customer, liability, revenue recognized	8,400
Homebuilding revenue
Disaggregation of Revenue [Line Items]
Total revenue	400,982	367,754
Land sales and other revenue
Disaggregation of Revenue [Line Items]
Total revenue	$ 1,058	$ 4,735