Revenue Recognition - Schedule of revenue by contract type (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2026	Sep. 30, 2025	Sep. 30, 2026	Sep. 30, 2025
Disaggregation of Revenue [Line Items]
Contract revenues	$ 1,259,032	$ 950,400	$ 3,341,139	$ 2,684,345
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	$ 809,714	$ 541,837	$ 2,002,517	$ 1,517,192
Fixed price \| Product concentration risk \| Revenue benchmark
Disaggregation of Revenue [Line Items]
Concentration risk, percent	64.30%	57.00%	59.90%	56.50%
Unit price
Disaggregation of Revenue [Line Items]
Contract revenues	$ 232,341	$ 224,697	$ 686,160	$ 605,734
Unit price \| Product concentration risk \| Revenue benchmark
Disaggregation of Revenue [Line Items]
Concentration risk, percent	18.50%	23.60%	20.60%	22.60%
T&E
Disaggregation of Revenue [Line Items]
Contract revenues	$ 216,977	$ 183,866	$ 652,462	$ 561,419
T&E \| Product concentration risk \| Revenue benchmark
Disaggregation of Revenue [Line Items]
Concentration risk, percent	17.20%	19.40%	19.50%	20.90%
T&D
Disaggregation of Revenue [Line Items]
Contract revenues	$ 554,544	$ 503,436	$ 1,619,536	$ 1,471,479
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	$ 173,356	$ 160,811	$ 482,171	$ 512,379
T&D \| Fixed price \| Product concentration risk \| Revenue benchmark
Disaggregation of Revenue [Line Items]
Concentration risk, percent	31.30%	31.90%	29.80%	34.80%
T&D \| Unit price
Disaggregation of Revenue [Line Items]
Contract revenues	$ 208,967	$ 204,438	$ 635,585	$ 547,562
T&D \| Unit price \| Product concentration risk \| Revenue benchmark
Disaggregation of Revenue [Line Items]
Concentration risk, percent	37.70%	40.60%	39.20%	37.20%
T&D \| T&E
Disaggregation of Revenue [Line Items]
Contract revenues	$ 172,221	$ 138,187	$ 501,780	$ 411,538
T&D \| T&E \| Product concentration risk \| Revenue benchmark
Disaggregation of Revenue [Line Items]
Concentration risk, percent	31.00%	27.50%	31.00%	28.00%
C&I
Disaggregation of Revenue [Line Items]
Contract revenues	$ 704,488	$ 446,964	$ 1,721,603	$ 1,212,866
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	$ 636,358	$ 381,026	$ 1,520,346	$ 1,004,813
C&I \| Fixed price \| Product concentration risk \| Revenue benchmark
Disaggregation of Revenue [Line Items]
Concentration risk, percent	90.30%	85.30%	88.30%	82.80%
C&I \| Unit price
Disaggregation of Revenue [Line Items]
Contract revenues	$ 23,374	$ 20,259	$ 50,575	$ 58,172
C&I \| Unit price \| Product concentration risk \| Revenue benchmark
Disaggregation of Revenue [Line Items]
Concentration risk, percent	3.30%	4.50%	2.90%	4.80%
C&I \| T&E
Disaggregation of Revenue [Line Items]
Contract revenues	$ 44,756	$ 45,679	$ 150,682	$ 149,881
C&I \| T&E \| Product concentration risk \| Revenue benchmark
Disaggregation of Revenue [Line Items]
Concentration risk, percent	6.40%	10.20%	8.80%	12.40%