Operating Segments (Tables)

12 Months Ended

Sep. 30, 2020

Segment Reporting [Abstract]

Schedule of Segment Reporting Information, by Segment [Table Text Block]

		Year Ended September 30, 2020
		Communications		Residential		Infrastructure Solutions		Commercial & Industrial		Corporate		Total
Revenues		$	395,141	$	411,790	$	128,379	$	255,546	$	—	$	1,190,856
Cost of services		317,013		318,034		93,358		234,492		—		962,897
Gross profit		78,128		93,756		35,021		21,054		—		227,959
Selling, general and administrative		37,674		63,668		20,418		32,128		17,023		170,911
Goodwill impairment expense		—		—		—		6,976		—		6,976
Contingent consideration		—		—		—		(11)		—		(11)
Loss (gain) on sale of assets		8		2		35		(45)		—		—
Income (loss) from operations		$	40,446	$	30,086	$	14,568	$	(17,994)	$	(17,023)	$	50,083
Other data:
	Depreciation and amortization expense	$	1,351	$	2,276	$	6,020	$	2,768	$	93	$	12,508
	Capital expenditures	$	830	$	1,459	$	795	$	1,362	$	299	$	4,745
	Total assets	$	154,808	$	110,998	$	124,640	$	68,318	$	101,764	$	560,528

		Year Ended September 30, 2019
		Communications		Residential		Infrastructure Solutions		Commercial & Industrial		Corporate		Total
Revenues		$	321,246	$	313,336	$	136,790	$	305,624	$	—	$	1,076,996
Cost of services		264,746		248,562		105,863		275,722		—		894,893
Gross profit		56,500		64,774		30,927		29,902		—		182,103
Selling, general and administrative		31,850		46,864		18,664		27,815		15,382		140,575
Contingent consideration		(97)		—		(277)		—		—		(374)
Loss (gain) on sale of assets		(6)		(17)		105		(30)		—		52
Income (loss) from operations		$	24,753	$	17,927	$	12,435	$	2,117	$	(15,382)	$	41,850
Other data:
	Depreciation and amortization expense	$	1,513	$	852	$	4,528	$	2,563	$	101	$	9,557
	Capital expenditures	$	973	$	1,412	$	1,377	$	2,402	$	136	$	6,300
	Total assets	$	109,263	$	63,903	$	116,867	$	82,050	$	73,175	$	445,258

		Year Ended September 30, 2018
		Communications		Residential		Infrastructure Solutions		Commercial & Industrial		Corporate		Total
Revenues		$	219,655	$	285,711	$	97,163	$	274,299	$	—	$	876,828
Cost of services		179,518		227,355		75,337		244,656		—		726,866
Gross profit		40,137		58,356		21,826		29,643		—		149,962
Selling, general and administrative		26,003		41,401		18,293		27,031		11,192		123,920
Contingent consideration		(85)		—		288		(100)		—		103
Loss (gain) on sale of assets		(4)		8		18		(37)		—		(15)
Income (loss) from operations		$	14,223	$	16,947	$	3,227	$	2,749	$	(11,192)	$	25,954
Other data:
	Depreciation and amortization expense	$	1,247	$	637	$	4,672	$	2,197	$	107	$	8,860
	Capital expenditures	$	647	$	932	$	735	$	2,216	$	33	$	4,563
	Total assets	$	80,528	$	55,176	$	109,506	$	89,729	$	87,055	$	421,994