Income Taxes - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Income Tax Disclosure [Abstract]
Income tax expense (benefit), including discontinued operations	$ (2,200)		$ 4,300	$ (44,300)	$ 113,200
Inventory impairments and abandonments	0	$ 147,600	$ 168	148,618	168
Tax credit				9,800	$ 2,800
Deferred tax assets, tax credit carryforwards	$ 9,600			$ 9,600