Property, Plant, and Equipment (Narrative) (Details) - USD ($) $ in Thousands		3 Months Ended			6 Months Ended		12 Months Ended
		Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2021	Mar. 31, 2020	Sep. 30, 2020
Property, Plant and Equipment [Line Items]
Net (gain) loss on sales of assets	[1]	$ 1,354	$ 10		$ 1,942	$ 13,557
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)		$ 13,522
Disposal Groups [Member]
Property, Plant and Equipment [Line Items]
Impairment of assets held for sale					$ 37,902
Disposal Groups [Member] | Plant, Property and Equipment [Member]
Property, Plant and Equipment [Line Items]
Impairment of assets held for sale							$ 13,421

[1] Included in net gain on sale of assets and businesses 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.