Goodwill and Intangible Assets Goodwill (Details) $ in Thousands	3 Months Ended
Dec. 31, 2020 USD ($)
Goodwill [Line Items]
Goodwill	$ 53,763
Goodwill, Acquired During Period	32,686
Goodwill	86,449
Commercial and Industrial [Member]
Goodwill [Line Items]
Goodwill	0
Goodwill	0
Residential [Member]
Goodwill [Line Items]
Goodwill	16,219
Goodwill, Acquired During Period	28,121
Goodwill	44,340
Infrastructure Solutions [Member]
Goodwill [Line Items]
Goodwill	34,728
Goodwill, Acquired During Period	4,565
Goodwill	39,293
Communications [Member]
Goodwill [Line Items]
Goodwill	2,816
Goodwill	$ 2,816

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 45
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=77989000&loc=SL49117168-202975

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=99380562&loc=d3e13770-109266

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
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-Paragraph 1
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-URI http://asc.fasb.org/extlink&oid=108376223&loc=d3e13816-109267

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