Segment Information - Reconciliation (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Reconciliation of segment operating income to income from continuing operations before income taxes
Segment operating income (loss)	$ 35,225	$ 834	$ 89,726	$ (82,543)
Income from asset sales	4,313	1,862	15,133	17,593
Corporate general and administrative costs and corporate depreciation	(33,321)	(30,724)	(96,375)	(77,914)
Operating income (loss) from continuing operations	6,217	(28,028)	8,484	(142,864)
Other income (expense)
Interest and dividend income	2,109	1,700	5,680	4,028
Interest expense	(5,993)	(6,364)	(17,794)	(17,503)
Other	28	(911)	437	(350)
Total other income (expense)	(3,856)	(5,575)	(11,677)	(13,825)
Income (loss) from continuing operations before income taxes	$ 2,361	$ (33,603)	$ (3,193)	$ (156,689)