Concentration of Risk and Enterprise Wide Disclosures (Tables)

3 Months Ended

Mar. 31, 2021

Trade and contract retainage receivables

Concentration Risk [Line Items]

Schedules of concentration of risk, by risk factor

	March 31, 2021				December 31, 2020
Federal Government	$	4,341	3	%	$	4,826	4	%
State Governments		220	-	%		—	-	%
Local Governments		22,444	17	%		17,823	13	%
Private Companies		103,914	79	%		110,616	83	%
Gross receivables		130,919	99	%		133,265	100	%
Allowance for credit losses		(323)				(411)
Net receivables	$	130,596			$	132,854

Contract revenues

Concentration Risk [Line Items]

Schedules of concentration of risk, by risk factor

	Three months ended March 31,
	2021		%		2020		%
Federal Government	$	12,764	8	%	$	5,319	3	%
State Governments		168	-	%		12,232	7	%
Local Government		33,516	22	%		52,012	31	%
Private Companies		106,861	70	%		97,057	59	%
Total contract revenues	$	153,309	100	%	$	166,620	100	%