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Basis of Presentation and Summary of Significant Accounting Policies - Revenue Recognition (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Sep. 30, 2018
Disaggregation of Revenue [Line Items]
Total revenue	$ 482,738	$ 511,521	$ 1,306,038	$ 1,339,188
Customer deposits	19,681		19,681		$ 14,903
Contract with customer, liability, revenue recognized	1,000		13,400
Homebuilding revenue
Disaggregation of Revenue [Line Items]
Total revenue	482,316	506,964	1,304,243	1,315,833
Land sales and other revenue
Disaggregation of Revenue [Line Items]
Total revenue	$ 422	$ 4,557	$ 1,795	$ 23,355