Concentration of Risk and Enterprise Wide Disclosures (Tables)

12 Months Ended

Dec. 31, 2020

Trade and contract retainage receivables

Concentration Risk [Line Items]

Schedules of concentration of risk, by risk factor

	December 31, 2020				December 31, 2019
Federal Government	$	4,826	4	%	$	4,765	3	%
State Governments		—	-	%		5,864	4	%
Local Governments		17,823	13	%		41,944	26	%
Private Companies		110,616	83	%		109,114	67	%
Gross receivables		133,265	100	%		161,687	100	%
Allowance for credit losses		(411)				(2,600)
Net receivables	$	132,854			$	159,087

Contract revenues

Concentration Risk [Line Items]

Schedules of concentration of risk, by risk factor

	2020		%		2019		%		2018		%
Federal Government	$	51,793	7	%	$	46,425	6	%	$	42,143	8	%
State Governments		27,574	4	%		47,831	7	%		30,470	6	%
Local Government		202,839	29	%		212,958	30	%		107,478	21	%
Private Companies		427,736	60	%		401,176	57	%		340,803	65	%
Total contract revenues	$	709,942	100	%	$	708,390	100	%	$	520,894	100	%