Concentration of Risk and Enterprise Wide Disclosures (Tables)

6 Months Ended

Jun. 30, 2021

Trade and contract retainage receivables

Concentration Risk [Line Items]

Schedules of concentration of risk, by risk factor

	June 30, 2021				December 31, 2020
Federal Government	$	6,392	5	%	$	4,826	4	%
State Governments		215	-	%		—	-	%
Local Governments		15,170	12	%		17,823	13	%
Private Companies		106,605	83	%		110,616	83	%
Gross receivables		128,382	100	%		133,265	100	%
Allowance for credit losses		(323)				(411)
Net receivables	$	128,059			$	132,854

Contract revenues

Concentration Risk [Line Items]

Schedules of concentration of risk, by risk factor

	Three months ended June 30,								Six months ended June 30,
	2021		%		2020		%		2021		%		2020		%
Federal Government	$	12,345	8	%	$	10,902	6	%	$	25,109	8	%	$	16,221	4	%
State Governments		246	-	%		9,092	5	%		414	-	%		21,324	6	%
Local Government		38,576	26	%		51,848	28	%		72,092	24	%		103,860	30	%
Private Companies		94,708	65	%		111,871	61	%		201,569	67	%		208,928	60	%
Total contract revenues	$	145,875	99	%	$	183,713	100	%	$	299,184	99	%	$	350,333	100	%