Revenue Recognition - Schedule of revenue by contract type (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Disaggregation of Revenue [Line Items]
Contract revenues	$ 950,400	$ 888,043	$ 2,684,345	$ 2,532,495
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	$ 541,837	$ 528,190	$ 1,517,192	$ 1,557,551
Fixed price \| Product concentration risk \| Revenue benchmark
Disaggregation of Revenue [Line Items]
Concentration risk, Percent	57.00%	59.50%	56.50%	61.50%
Unit price
Disaggregation of Revenue [Line Items]
Contract revenues	$ 224,697	$ 193,186	$ 605,734	$ 502,577
Unit price \| Product concentration risk \| Revenue benchmark
Disaggregation of Revenue [Line Items]
Concentration risk, Percent	23.60%	21.70%	22.60%	19.80%
T&E
Disaggregation of Revenue [Line Items]
Contract revenues	$ 183,866	$ 166,667	$ 561,419	$ 472,367
T&E \| Product concentration risk \| Revenue benchmark
Disaggregation of Revenue [Line Items]
Concentration risk, Percent	19.40%	18.80%	20.90%	18.70%
T&D
Disaggregation of Revenue [Line Items]
Contract revenues	$ 503,436	$ 481,876	$ 1,471,479	$ 1,430,480
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	$ 160,811	$ 197,087	$ 512,379	$ 654,969
T&D \| Fixed price \| Product concentration risk \| Revenue benchmark
Disaggregation of Revenue [Line Items]
Concentration risk, Percent	31.90%	40.90%	34.80%	45.80%
T&D \| Unit price
Disaggregation of Revenue [Line Items]
Contract revenues	$ 204,438	$ 169,337	$ 547,562	$ 443,589
T&D \| Unit price \| Product concentration risk \| Revenue benchmark
Disaggregation of Revenue [Line Items]
Concentration risk, Percent	40.60%	35.10%	37.20%	31.00%
T&D \| T&E
Disaggregation of Revenue [Line Items]
Contract revenues	$ 138,187	$ 115,452	$ 411,538	$ 331,922
T&D \| T&E \| Product concentration risk \| Revenue benchmark
Disaggregation of Revenue [Line Items]
Concentration risk, Percent	27.50%	24.00%	28.00%	23.20%
C&I
Disaggregation of Revenue [Line Items]
Contract revenues	$ 446,964	$ 406,167	$ 1,212,866	$ 1,102,015
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	$ 381,026	$ 331,103	$ 1,004,813	$ 902,582
C&I \| Fixed price \| Product concentration risk \| Revenue benchmark
Disaggregation of Revenue [Line Items]
Concentration risk, Percent	85.30%	81.50%	82.80%	81.90%
C&I \| Unit price
Disaggregation of Revenue [Line Items]
Contract revenues	$ 20,259	$ 23,849	$ 58,172	$ 58,988
C&I \| Unit price \| Product concentration risk \| Revenue benchmark
Disaggregation of Revenue [Line Items]
Concentration risk, Percent	4.50%	5.90%	4.80%	5.40%
C&I \| T&E
Disaggregation of Revenue [Line Items]
Contract revenues	$ 45,679	$ 51,215	$ 149,881	$ 140,445
C&I \| T&E \| Product concentration risk \| Revenue benchmark
Disaggregation of Revenue [Line Items]
Concentration risk, Percent	10.20%	12.60%	12.40%	12.70%