Contract Assets and Liabilities - Additional Information (Details) $ in Millions	12 Months Ended
	Dec. 31, 2019 USD ($) project	Dec. 31, 2018 USD ($) project
Property, Plant and Equipment [Line Items]
Percentage completed of certain milestones	10.00%
Net amount of unresolved change orders and claims	$ 38.4	$ 23.1
Western Pennsylvania Project
Property, Plant and Equipment [Line Items]
Revision in contract estimates recorded project write down	$ 1.4
Number of projects | project	1
Southern California Region Service Project
Property, Plant and Equipment [Line Items]
Revision in contract estimates recorded project write down	$ 0.4
Number of projects | project	1
Gross profit write up	$ 0.4
Mid-Atlantic Region Service Project
Property, Plant and Equipment [Line Items]
Number of projects | project	1	10
Gross profit write up	$ 0.3
Mid-Atlantic Service Project
Property, Plant and Equipment [Line Items]
Revision in contract estimates recorded project write down		$ 1.7
Number of projects | project		1
Service Project
Property, Plant and Equipment [Line Items]
Number of projects | project		1
Gross profit write up		$ 0.5
Sixteen Construction Projects
Property, Plant and Equipment [Line Items]
Revision in contract estimates recorded project write down	$ 12.4
Number of projects | project	16
Twelve Construction Projects
Property, Plant and Equipment [Line Items]
Revision in contract estimates recorded project write down	$ 9.9
Number of projects | project	12
Ten Construction Projects
Property, Plant and Equipment [Line Items]
Number of projects | project	10
Gross profit write up	$ 4.7
Fourteen Construction Projects
Property, Plant and Equipment [Line Items]
Revision in contract estimates recorded project write down		$ 16.6
Number of projects | project		14
Six Construction Projects
Property, Plant and Equipment [Line Items]
Number of projects | project		6
Gross profit write up		$ 3.3