Goodwill and Intangible Assets Goodwill (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Goodwill [Line Items]
Goodwill, beginning		$ 50,622	$ 50,702
Goodwill, Acquired During Period		10,117
Goodwill, Written off Related to Sale of Business Unit			(119)
Goodwill, Purchase Accounting Adjustments			39
Impairment expense	$ (6,976)	(6,976)	0	$ 0
Goodwill, ending	53,763	53,763	50,622	50,702
Communications [Member]
Goodwill [Line Items]
Goodwill, beginning		2,816	2,816
Impairment expense		0
Goodwill, ending	2,816	2,816	2,816	2,816
Residential [Member]
Goodwill [Line Items]
Goodwill, beginning		10,018	9,979
Goodwill, Acquired During Period		6,201
Goodwill, Purchase Accounting Adjustments			39
Impairment expense		0
Goodwill, ending	16,219	16,219	10,018	9,979
Infrastructure Solutions [Member]
Goodwill [Line Items]
Goodwill, beginning		30,812	30,931
Goodwill, Acquired During Period		3,916
Goodwill, Written off Related to Sale of Business Unit			(119)
Impairment expense		0
Goodwill, ending	34,728	34,728	30,812	30,931
Commercial and Industrial [Member]
Goodwill [Line Items]
Goodwill, beginning		6,976	6,976
Impairment expense		(6,976)
Goodwill, ending	$ 0	$ 0	$ 6,976	$ 6,976