Organization, Business and Basis of Presentation (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2021 USD ($) $ / shares	Jun. 30, 2020 USD ($) $ / shares	Jun. 30, 2021 USD ($) segment $ / shares	Jun. 30, 2020 USD ($) $ / shares
Organization Consolidation and Presentation of Financial Statements [Line Items]
Number of business segments (segment) | segment			2
Capital contributions to joint venture	$ 0		$ 0
Foreign currency gains (losses)			(100,000)	$ 0
Revenue recognized, related to change orders and claims included as contract price adjustments			6,000,000.0	40,100,000
Increase (decrease) in operating income	29,665,000	$ 19,342,000	57,076,000	35,750,000
Increase (decrease) in net income	$ 21,219,000	$ 13,385,000	$ 41,147,000	$ 23,317,000
Increase (decrease) in diluted earnings per common share (in dollars per share) | $ / shares	$ 1.24	$ 0.80	$ 2.41	$ 1.39
Contracts Accounted for under Percentage of Completion
Organization Consolidation and Presentation of Financial Statements [Line Items]
Increase (decrease) in consolidated gross margin	0.80%	0.20%	0.30%	(0.10%)
Increase (decrease) in operating income	$ 5,100,000	$ 1,200,000	$ 3,900,000	$ (700,000)
Increase (decrease) in net income	$ 3,600,000	$ 900,000	$ 2,700,000	$ (500,000)
Increase (decrease) in diluted earnings per common share (in dollars per share) | $ / shares	$ 0.21	$ 0.05	$ 0.16	$ (0.03)
Huen Electric Inc
Organization Consolidation and Presentation of Financial Statements [Line Items]
Distributions to partners	$ 0		$ 0