Revenue Recognition (Tables)

12 Months Ended

Sep. 30, 2020

Revenue Recognition and Deferred Revenue [Abstract]

Disaggregation of Revenue [Table Text Block]

	Year Ended September 30,
	2020		2019		2018
Communications	$	395,141	$	321,246	$	219,655
Residential
Single-family	239,140		212,358		190,379
Multi-family and Other	172,650		100,978		95,332
Total Residential	411,790		313,336		285,711
Infrastructure Solutions
Industrial Services	40,701		48,948		44,701
Custom Power Solutions	87,678		87,842		52,462
Total Infrastructure Solutions	128,379		136,790		97,163
Commercial & Industrial	255,546		305,624		274,299
Total Revenue	$	1,190,856	$	1,076,996	$	876,828

	Year Ended September 30, 2020
		Communications		Residential		Infrastructure Solutions		Commercial & Industrial		Total
Fixed-price		$	309,567	$	411,790	$	121,922	$	241,864	$	1,085,143
Time-and-material		85,574		—		6,457		13,682		105,713
Total revenue		$	395,141	$	411,790	$	128,379	$	255,546	$	1,190,856
	Year Ended September 30, 2019
		Communications		Residential		Infrastructure Solutions		Commercial & Industrial		Total
Fixed-price		$	229,143	$	313,336	$	129,096	$	286,319	$	957,894
Time-and-material		92,103		—		7,694		19,305		119,102
Total revenue		$	321,246	$	313,336	$	136,790	$	305,624	$	1,076,996
	Year Ended September 30, 2018
		Communications		Residential		Infrastructure Solutions		Commercial & Industrial		Total
Fixed-price		$	166,258	$	285,711	$	90,155	$	244,464	$	786,588
Time-and-material		53,397		—		7,008		29,835		90,240
Total revenue		$	219,655	$	285,711	$	97,163	$	274,299	$	876,828