Contract Assets and Liabilities - Additional Information (Details) $ in Millions	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2020 USD ($) project	Jun. 30, 2019 USD ($) project	Jun. 30, 2020 USD ($) project	Jun. 30, 2019 USD ($) project	Dec. 31, 2019 USD ($)
Property, Plant and Equipment [Line Items]
Percentage completed of certain milestones					10.00%
Claims and unapproved change orders	$ 39.4		$ 39.4		$ 38.4
Michigan Project
Property, Plant and Equipment [Line Items]
Number of Projects | project		1		1
Gross profit write up				$ 1.4
Four Construction Projects
Property, Plant and Equipment [Line Items]
Number of Projects | project	4		4
Project write downs	$ 1.5
Four Construction Projects | Southern California Region Project
Property, Plant and Equipment [Line Items]
Number of Projects | project		4		4
Project write downs				$ 2.2
Two Construction Projects
Property, Plant and Equipment [Line Items]
Number of Projects | project	2		2
Project write downs	$ 0.7
Gross profit write up			$ 1.2
Two Construction Projects | Southern California Region Project
Property, Plant and Equipment [Line Items]
Number of Projects | project	2		2
Eight Construction Projects
Property, Plant and Equipment [Line Items]
Number of Projects | project	8		8
Project write downs			$ 5.2
One Construction Project
Property, Plant and Equipment [Line Items]
Number of Projects | project		1		1
Gross profit write up		$ 0.3
One Construction Project | Southern California Region Project
Property, Plant and Equipment [Line Items]
Number of Projects | project		1		1
Project write downs				$ 0.3
One Construction Project | Mid-Atlantic Region Project
Property, Plant and Equipment [Line Items]
Number of Projects | project		1		1
Project write downs				$ 0.5
One Service Project
Property, Plant and Equipment [Line Items]
Number of Projects | project		1		1
Gross profit write up		$ 0.3
One Service Project | Mid-Atlantic Region Project
Property, Plant and Equipment [Line Items]
Number of Projects | project		1		1
Gross profit write up				$ 0.3
Three Construction Projects | Southern California Region Project
Property, Plant and Equipment [Line Items]
Number of Projects | project		3		3
Project write downs		$ 1.9
Three Construction Projects | Mid-Atlantic Region Project
Property, Plant and Equipment [Line Items]
Number of Projects | project		3		3
Gross profit write up				$ 1.0
Six Construction Projects
Property, Plant and Equipment [Line Items]
Number of Projects | project		6		6
Gross profit write up				$ 3.0
Seven Construction Projects
Property, Plant and Equipment [Line Items]
Number of Projects | project		7		7
Project write downs				$ 3.5