Supplemental Cash Flow Information - Supplemental Disclosure of Non-cash Activity (Details) - USD ($) $ in Thousands	6 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Supplemental disclosure of non-cash activity:
Non-cash land acquisitions	$ 5,197	$ 8,265
Land acquisitions for debt	6,304	0
Supplemental disclosure of cash activity:
Interest payments	50,153	60,998
Income tax payments	91	471
Tax refunds received	$ 3	$ 67