Concentration of Risk and Enterprise Wide Disclosures (Tables)

6 Months Ended

Jun. 30, 2020

Trade and contract retainage receivables

Concentration Risk [Line Items]

Schedules of concentration of risk, by risk factor

	June 30, 2020				December 31, 2019
Federal Government	$	1,665	1	%	$	4,765	3	%
State Governments		1,055	1	%		5,864	4	%
Local Governments		22,741	17	%		41,944	26	%
Private Companies		111,659	81	%		109,114	67	%
Gross receivables		137,120	100	%		161,687	100	%
Allowance for credit losses		(3,011)				(2,600)
Net receivables	$	134,109			$	159,087

Contract revenues

Concentration Risk [Line Items]

Schedules of concentration of risk, by risk factor

	Three months ended June 30,								Six months ended June 30,
	2020		%		2019		%		2020		%		2019		%
Federal Government	$	10,902	6	%	$	12,301	8	%	$	16,221	4	%	$	22,578	7	%
State Governments		9,092	5	%		10,286	6	%		21,324	6	%		14,341	5	%
Local Government		51,848	28	%		51,599	31	%		103,860	30	%		96,029	31	%
Private Companies		111,871	61	%		91,799	55	%		208,928	60	%		176,142	57	%
Total contract revenues	$	183,713	100	%	$	165,985	100	%	$	350,333	100	%	$	309,090	100	%