Supplemental Cash Flow Information - Supplemental Disclosure of Non-cash Activity (Details) - USD ($) $ in Thousands	9 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Sep. 30, 2017
Supplemental disclosure of non-cash activity:
Non-cash land acquisitions	$ 0	$ 8,346
Land acquisitions for debt	0	6,305
Supplemental disclosure of cash activity:
Interest payments	60,025	60,847
Income tax payments	495	548
Tax refunds received	39	3
Reconciliation of cash, cash equivalents, and restricted cash:
Cash and cash equivalents	136,298	168,381	$ 292,147
Restricted cash	12,167	12,735	$ 12,462
Total cash, cash equivalents, and restricted cash shown in the statement of cash flows	$ 148,465	$ 181,116