Revenue Recognition (Tables)

9 Months Ended

Jun. 30, 2020

Revenue Recognition and Deferred Revenue [Abstract]

Disaggregation of Revenue [Table Text Block]

	Three Months Ended June 30,				Nine Months Ended June 30,
	2020		2019		2020		2019
Commercial & Industrial	$	56,778	$	75,370	$	190,481	$	227,928
Communications	96,500		90,438		276,779		230,200
Infrastructure Solutions
Industrial Services	9,753		12,339		31,588		36,707
Custom Power Solutions	22,189		23,770		60,937		63,331
Total Infrastructure Solutions	31,942		36,109		92,525		100,038
Residential
Single-family	62,239		54,200		176,071		156,168
Multi-family and Other	45,666		26,516		124,589		69,055
Total Residential	107,905		80,716		300,660		225,223
Total Revenue	$	293,125	$	282,633	$	860,445	$	783,389

	Three Months Ended June 30, 2020
		Commercial & Industrial		Communications		Infrastructure Solutions		Residential		Total
Fixed-price		$	53,811	$	79,801	$	30,504	$	107,905	$	272,021
Time-and-material			2,967		16,699		1,438		—		21,104
Total revenue		$	56,778	$	96,500	$	31,942	$	107,905	$	293,125
	Three Months Ended June 30, 2019
		Commercial & Industrial		Communications		Infrastructure Solutions		Residential		Total
Fixed-price		$	70,917	$	65,219	$	34,244	$	80,716	$	251,096
Time-and-material			4,453		25,219		1,865		—		31,537
Total revenue		$	75,370	$	90,438	$	36,109	$	80,716	$	282,633
	Nine Months Ended June 30, 2020
		Commercial & Industrial		Communications		Infrastructure Solutions		Residential		Total
Fixed-price		$	180,425	$	213,205	$	87,479	$	300,660	$	781,769
Time-and-material			10,056		63,574		5,046		—		78,676
Total revenue		$	190,481	$	276,779	$	92,525	$	300,660	$	860,445
	Nine Months Ended June 30, 2019
		Commercial & Industrial		Communications		Infrastructure Solutions		Residential		Total
Fixed-price		$	213,214	$	162,650	$	93,853	$	225,223	$	694,940
Time-and-material			14,714		67,550		6,185		—		88,449
Total revenue		$	227,928	$	230,200	$	100,038	$	225,223	$	783,389

Contract with Customer, Asset and Liability [Table Text Block]

The net asset (liability) position for contracts in process consisted of the following:

	June 30,		September 30,
	2020		2019
Costs and estimated earnings on uncompleted contracts	$	868,267	$	761,401
Less: Billings to date and unbilled accounts receivable		(898,620)		(772,104)
	$	(30,353)	$	(10,703)

The net asset (liability) position for contracts in process included in the accompanying consolidated balance sheets was as follows:

	June 30,		September 30,
	2020		2019
Costs and estimated earnings in excess of billings	$	25,821	$	29,860
Billings in excess of costs and estimated earnings		(56,174)		(40,563)
	$	(30,353)	$	(10,703)