Fair Value Measurements - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Land Held for Sale	$ 38,588	$ 0	$ 38,588	$ 0
Discontinued Operations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Land Held for Sale	0	0	0	450
Continuing Operations
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impairment charges on projects in progress	$ 109,023	$ 0	$ 110,030	$ 0