Revenue Recognition (Tables)

9 Months Ended

Jun. 30, 2019

Revenue Recognition and Deferred Revenue [Abstract]

Disaggregation of Revenue [Table Text Block]

	Three Months Ended June 30,				Nine Months Ended June 30,
	2019		2018		2019		2018
Commercial & Industrial	$	75,370	$	78,156	$	227,928	$	196,747
Communications	90,438		54,368		230,200		159,071
Infrastructure Solutions
Industrial Services	12,339		11,417		36,707		32,874
Custom Power Solutions	23,770		13,439		63,331		37,533
Total	36,109		24,856		100,038		70,407
Residential
Single-family	54,200		51,028		156,168		139,235
Multi-family and Other	26,516		24,168		69,055		71,093
Total	80,716		75,196		225,223		210,328
Total Revenue	$	282,633	$	232,576	$	783,389	$	636,553

	Three Months Ended June 30, 2019
		Commercial & Industrial		Communications		Infrastructure Solutions		Residential		Total
Fixed-price		$	70,917	$	65,219	$	29,925	$	80,716	$	246,777
Time-and-material			4,453		25,219		6,184		—		35,856
Total revenue		$	75,370	$	90,438	$	36,109	$	80,716	$	282,633
	Three Months Ended June 30, 2018
		Commercial & Industrial		Communications		Infrastructure Solutions		Residential		Total
Fixed-price		$	68,762	$	42,927	$	19,865	$	75,196	$	206,750
Time-and-material			9,394		11,441		4,991		—		25,826
Total revenue		$	78,156	$	54,368	$	24,856	$	75,196	$	232,576
	Nine Months Ended June 30, 2019
		Commercial & Industrial		Communications		Infrastructure Solutions		Residential		Total
Fixed-price		$	213,214	$	162,650	$	87,566	$	225,223	$	688,653
Time-and-material			14,714		67,550		12,472		—		94,736
Total revenue		$	227,928	$	230,200	$	100,038	$	225,223	$	783,389
	Nine Months Ended June 30, 2018
		Commercial & Industrial		Communications		Infrastructure Solutions		Residential		Total
Fixed-price		$	175,866	$	124,428	$	60,172	$	210,328	$	570,794
Time-and-material			20,881		34,643		10,235		—		65,759
Total revenue		$	196,747	$	159,071	$	70,407	$	210,328	$	636,553

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,
	2019			2018
Costs and estimated earnings on uncompleted contracts	$	720,469		$	539,226
Less: Billings to date and unbilled accounts receivable		(721,521	)		(541,606	)
	$	(1,052	)	$	(2,380	)

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

	June 30,			September 30,
	2019			2018
Costs and estimated earnings in excess of billings	$	34,807		$	31,446
Billings in excess of costs and estimated earnings		(35,859	)		(33,826	)
	$	(1,052	)	$	(2,380	)