Revenue Recognition - Schedule of revenue by contract type (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Disaggregation of Revenue [Line Items]
Contract revenues	$ 888,616	$ 708,114	$ 1,700,232	$ 1,344,738
Product concentration risk | Revenue benchmark
Disaggregation of Revenue [Line Items]
Concentration risk, Percent	100.00%	100.00%	100.00%	100.00%
Fixed price
Disaggregation of Revenue [Line Items]
Contract revenues	$ 574,757	$ 436,616	$ 1,109,612	$ 806,097
Fixed price | Product concentration risk | Revenue benchmark
Disaggregation of Revenue [Line Items]
Concentration risk, Percent	64.70%	61.70%	65.30%	59.90%
Unit price
Disaggregation of Revenue [Line Items]
Contract revenues	$ 163,487	$ 135,541	$ 294,837	$ 254,665
Unit price | Product concentration risk | Revenue benchmark
Disaggregation of Revenue [Line Items]
Concentration risk, Percent	18.40%	19.10%	17.30%	19.00%
T&E
Disaggregation of Revenue [Line Items]
Contract revenues	$ 150,372	$ 135,957	$ 295,783	$ 283,976
T&E | Product concentration risk | Revenue benchmark
Disaggregation of Revenue [Line Items]
Concentration risk, Percent	16.90%	19.20%	17.40%	21.10%
T&D
Disaggregation of Revenue [Line Items]
Contract revenues	$ 503,737	$ 415,235	$ 949,060	$ 780,091
T&D | Product concentration risk | Revenue benchmark
Disaggregation of Revenue [Line Items]
Concentration risk, Percent	100.00%	100.00%	100.00%	100.00%
T&D | Fixed price
Disaggregation of Revenue [Line Items]
Contract revenues	$ 261,348	$ 192,934	$ 490,582	$ 343,838
T&D | Fixed price | Product concentration risk | Revenue benchmark
Disaggregation of Revenue [Line Items]
Concentration risk, Percent	51.90%	46.50%	51.70%	44.10%
T&D | Unit price
Disaggregation of Revenue [Line Items]
Contract revenues	$ 139,929	$ 117,609	$ 253,637	$ 221,930
T&D | Unit price | Product concentration risk | Revenue benchmark
Disaggregation of Revenue [Line Items]
Concentration risk, Percent	27.80%	28.30%	26.70%	28.40%
T&D | T&E
Disaggregation of Revenue [Line Items]
Contract revenues	$ 102,460	$ 104,692	$ 204,841	$ 214,323
T&D | T&E | Product concentration risk | Revenue benchmark
Disaggregation of Revenue [Line Items]
Concentration risk, Percent	20.30%	25.20%	21.60%	27.50%
C&I
Disaggregation of Revenue [Line Items]
Contract revenues	$ 384,879	$ 292,879	$ 751,172	$ 564,647
C&I | Product concentration risk | Revenue benchmark
Disaggregation of Revenue [Line Items]
Concentration risk, Percent	100.00%	100.00%	100.00%	100.00%
C&I | Fixed price
Disaggregation of Revenue [Line Items]
Contract revenues	$ 313,409	$ 243,682	$ 619,030	$ 462,259
C&I | Fixed price | Product concentration risk | Revenue benchmark
Disaggregation of Revenue [Line Items]
Concentration risk, Percent	81.40%	83.20%	82.40%	81.90%
C&I | Unit price
Disaggregation of Revenue [Line Items]
Contract revenues	$ 23,558	$ 17,932	$ 41,200	$ 32,735
C&I | Unit price | Product concentration risk | Revenue benchmark
Disaggregation of Revenue [Line Items]
Concentration risk, Percent	6.10%	6.10%	5.50%	5.80%
C&I | T&E
Disaggregation of Revenue [Line Items]
Contract revenues	$ 47,912	$ 31,265	$ 90,942	$ 69,653
C&I | T&E | Product concentration risk | Revenue benchmark
Disaggregation of Revenue [Line Items]
Concentration risk, Percent	12.50%	10.70%	12.10%	12.30%