Property, Plant, and Equipment (Narrative) (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2020	Mar. 31, 2019
Property, Plant and Equipment [Line Items]
Net (gain) loss on sales of assets	[1]	$ (10)	$ 121	$ (13,557)	$ 200
Impairment of assets held for sale				37,902
Duarte Facility [Member]
Property, Plant and Equipment [Line Items]
Net (gain) loss on sales of assets				(13,522)
Disposal Groups [Member]
Property, Plant and Equipment [Line Items]
Impairment of assets held for sale				37,902
Disposal Group, Held-for-sale, Not Discontinued Operations [Member] | Duarte Facility [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment remaining		$ 2,520		2,520
Plant, Property and Equipment [Member] | Disposal Groups [Member]
Property, Plant and Equipment [Line Items]
Impairment of assets held for sale				$ 13,813

[1] Included in net (gain) loss on sale of assets for the six-months ended March 31, 2020 was the pre-tax gain on sale of Duarte real property in the amount of $13,522 recognized in the first quarter of fiscal year 2020.