Quarterly report pursuant to Section 13 or 15(d)

Contract Assets and Liabilities - Additional Information (Details)

v3.20.2
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