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- Definition

Amount, after accumulated amortization and accumulated impairment loss, of asset recognized from cost incurred to obtain or fulfill contract with customer.

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Amount, before allowance for credit loss, of right to consideration in exchange for good or service transferred to customer when right is conditioned on something other than passage of time, classified as current.

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Amount of obligation to transfer good or service to customer for which consideration has been received or is receivable, classified as current.

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Amount of revenue recognized that was previously included in balance of obligation to transfer good or service to customer for which consideration from customer has been received or is due.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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- Definition

Amount of transaction price allocated to performance obligation that has not been recognized as revenue.

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Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

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Amount received for services rendered and products shipped, but not yet billed, for non-contractual agreements due within one year or the normal operating cycle, if longer.

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Revenue Recognition (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
Revenue Recognition (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Sep. 30, 2020
Revenue Recognition and Deferred Revenue [Abstract]
Capitalized Contract Cost, Net	$ 100		$ 100
Unbilled Receivables, Current	18,525		18,525
Costs and estimated earnings in excess of billings	31,962		31,962		$ 29,937
Billings in excess of costs and estimated earnings	(67,235)		(67,235)		$ (55,739)
Contract with Customer, Liability, Revenue Recognized	25,851	$ 19,661	41,121	$ 29,692
Performance Obligation Next 12 Months	555,454		555,454
Revenue, Remaining Performance Obligation, Amount	668,716		668,716
Disaggregation of Revenue [Line Items]
Revenues	405,871	293,125	1,052,670	860,445
Contract with Customer, Liability, Revenue Recognized	25,851	19,661	41,121	29,692
Commercial and Industrial [Member]
Disaggregation of Revenue [Line Items]
Revenues	64,087	56,778	178,700	190,481
Communications [Member]
Disaggregation of Revenue [Line Items]
Revenues	116,218	96,500	309,460	276,779
Infrastructure Solutions [Member]
Disaggregation of Revenue [Line Items]
Revenues	39,117	31,942	108,234	92,525
Residential [Member]
Disaggregation of Revenue [Line Items]
Revenues	186,449	107,905	456,276	300,660
Fixed-price Contract [Member]
Disaggregation of Revenue [Line Items]
Revenues	365,655	272,021	955,360	781,769
Fixed-price Contract [Member] \| Commercial and Industrial [Member]
Disaggregation of Revenue [Line Items]
Revenues	60,444	53,811	170,134	180,425
Fixed-price Contract [Member] \| Communications [Member]
Disaggregation of Revenue [Line Items]
Revenues	81,521	79,801	226,086	213,205
Fixed-price Contract [Member] \| Infrastructure Solutions [Member]
Disaggregation of Revenue [Line Items]
Revenues	37,241	30,504	102,864	87,479
Fixed-price Contract [Member] \| Residential [Member]
Disaggregation of Revenue [Line Items]
Revenues	186,449	107,905	456,276	300,660
Time-and-materials Contract [Member]
Disaggregation of Revenue [Line Items]
Revenues	40,216	21,104	97,310	78,676
Time-and-materials Contract [Member] \| Commercial and Industrial [Member]
Disaggregation of Revenue [Line Items]
Revenues	3,643	2,967	8,566	10,056
Time-and-materials Contract [Member] \| Communications [Member]
Disaggregation of Revenue [Line Items]
Revenues	34,697	16,699	83,374	63,574
Time-and-materials Contract [Member] \| Infrastructure Solutions [Member]
Disaggregation of Revenue [Line Items]
Revenues	1,876	1,438	5,370	5,046
Time-and-materials Contract [Member] \| Residential [Member]
Disaggregation of Revenue [Line Items]
Revenues	0	0	0	0
industrial Services [Member] \| Infrastructure Solutions [Member]
Disaggregation of Revenue [Line Items]
Revenues	11,972	9,753	32,560	31,588
Custom Power Solutions [Member] \| Infrastructure Solutions [Member]
Disaggregation of Revenue [Line Items]
Revenues	27,145	22,189	75,674	60,937
Single Family Contracts [Member] \| Residential [Member]
Disaggregation of Revenue [Line Items]
Revenues	102,105	62,239	274,707	176,071
Multi Family and Other [Member] \| Residential [Member]
Disaggregation of Revenue [Line Items]
Revenues	$ 84,344	$ 45,666	$ 181,569	$ 124,589