Organization, Business and Basis of Presentation (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2021 USD ($) $ / shares	Sep. 30, 2020 USD ($) $ / shares	Sep. 30, 2021 USD ($) segment $ / shares	Sep. 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			4,000,000	19,100,000
Increase (decrease) in operating income	30,952,000	$ 24,929,000	88,028,000	60,679,000
Increase (decrease) in net income	$ 23,171,000	$ 17,292,000	$ 64,318,000	$ 40,609,000
Increase (decrease) in diluted earnings per common share (in dollars per share) | $ / shares	$ 1.35	$ 1.02	$ 3.75	$ 2.42
Contracts Accounted for under Percentage of Completion
Organization Consolidation and Presentation of Financial Statements [Line Items]
Increase (decrease) in consolidated gross margin	1.40%	(0.30%)	0.40%	(0.40%)
Increase (decrease) in operating income	$ 8,200,000	$ (1,900,000)	$ 7,200,000	$ (7,600,000)
Increase (decrease) in net income	$ 5,900,000	$ (1,500,000)	$ 5,200,000	$ (5,500,000)
Increase (decrease) in diluted earnings per common share (in dollars per share) | $ / shares	$ 0.35	$ (0.09)	$ 0.30	$ (0.33)
Huen Electric Inc
Organization Consolidation and Presentation of Financial Statements [Line Items]
Distributions to partners	$ 0		$ 0