Discontinued Operations - Cable Transaction and the Broken Arrow Facility (Details) - USD ($) $ in Thousands			12 Months Ended
	May 29, 2019	Nov. 29, 2018	Sep. 30, 2019	Sep. 30, 2020
Cable TV Business Segment
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Aggregate purchase price			$ 14,200
Discontinued Operations, Disposed of by Sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net assets sold				$ 15,695
Discontinued Operations, Disposed of by Sale | Cable TV Business Segment
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Aggregate purchase price	$ 7,128	$ 7,075	14,203
Net assets sold		4,763
Pretax gain	$ (3,805)	$ 2,312	$ (1,491)