Revenue Recognition - Schedule of revenue by contract type (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Disaggregation of Revenue [Line Items]
Contract revenues	$ 900,325	$ 828,890	$ 1,733,945	$ 1,644,452
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	$ 508,100	$ 521,561	$ 975,355	$ 1,029,361
Fixed price \| Product concentration risk \| Revenue benchmark
Disaggregation of Revenue [Line Items]
Concentration risk, Percent	56.40%	62.90%	56.30%	62.60%
Unit price
Disaggregation of Revenue [Line Items]
Contract revenues	$ 211,268	$ 156,930	$ 381,037	$ 309,391
Unit price \| Product concentration risk \| Revenue benchmark
Disaggregation of Revenue [Line Items]
Concentration risk, Percent	23.50%	18.90%	22.00%	18.80%
T&E
Disaggregation of Revenue [Line Items]
Contract revenues	$ 180,957	$ 150,399	$ 377,553	$ 305,700
T&E \| Product concentration risk \| Revenue benchmark
Disaggregation of Revenue [Line Items]
Concentration risk, Percent	20.10%	18.20%	21.70%	18.60%
T&D
Disaggregation of Revenue [Line Items]
Contract revenues	$ 506,273	$ 458,209	$ 968,043	$ 948,604
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	$ 178,118	$ 214,882	$ 351,568	$ 457,882
T&D \| Fixed price \| Product concentration risk \| Revenue benchmark
Disaggregation of Revenue [Line Items]
Concentration risk, Percent	35.20%	46.90%	36.30%	48.30%
T&D \| Unit price
Disaggregation of Revenue [Line Items]
Contract revenues	$ 191,022	$ 138,127	$ 343,124	$ 274,252
T&D \| Unit price \| Product concentration risk \| Revenue benchmark
Disaggregation of Revenue [Line Items]
Concentration risk, Percent	37.70%	30.10%	35.40%	28.90%
T&D \| T&E
Disaggregation of Revenue [Line Items]
Contract revenues	$ 137,133	$ 105,200	$ 273,351	$ 216,470
T&D \| T&E \| Product concentration risk \| Revenue benchmark
Disaggregation of Revenue [Line Items]
Concentration risk, Percent	27.10%	23.00%	28.30%	22.80%
C&I
Disaggregation of Revenue [Line Items]
Contract revenues	$ 394,052	$ 370,681	$ 765,902	$ 695,848
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	$ 329,982	$ 306,679	$ 623,787	$ 571,479
C&I \| Fixed price \| Product concentration risk \| Revenue benchmark
Disaggregation of Revenue [Line Items]
Concentration risk, Percent	83.80%	82.70%	81.40%	82.10%
C&I \| Unit price
Disaggregation of Revenue [Line Items]
Contract revenues	$ 20,246	$ 18,803	$ 37,913	$ 35,139
C&I \| Unit price \| Product concentration risk \| Revenue benchmark
Disaggregation of Revenue [Line Items]
Concentration risk, Percent	5.10%	5.10%	5.00%	5.10%
C&I \| T&E
Disaggregation of Revenue [Line Items]
Contract revenues	$ 43,824	$ 45,199	$ 104,202	$ 89,230
C&I \| T&E \| Product concentration risk \| Revenue benchmark
Disaggregation of Revenue [Line Items]
Concentration risk, Percent	11.10%	12.20%	13.60%	12.80%