Segment Information (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2024 USD ($) customer segment	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)
Segment Information
Number of reportable segments | segment	2
Total assets	$ 4,711,088	$ 3,305,579
Revenue	7,027,476	5,206,760	$ 4,140,364
Cost of services	5,551,065	4,216,251	3,398,756
Gross profit	1,476,411	990,509	741,608
Selling, general and administrative expenses	730,072	574,423	489,344
Gain on sale of assets	(3,030)	(2,302)	(1,585)
Operating income	749,369	418,388	253,849
Amortization of identifiable intangible assets	97,266	43,404	47,795
Depreciation expense	48,219	38,162	33,552
Capital expenditures	$ 111,071	$ 94,838	48,359
Revenue from contract with customer benchmark | Customer concentration
Segment Information
Number of Customers | customer	1
Revenue from contract with customer benchmark | Customer concentration | Customer One
Segment Information
Single customer, percentage	13.30%	13.80%
Operating Segments | Mechanical Segment
Segment Information
Total assets	$ 3,162,677	$ 2,180,021
Revenue	5,527,604	3,946,022	3,178,475
Cost of services	4,413,108	3,195,916	2,597,856
Gross profit	1,114,496	750,106	580,619
Selling, general and administrative expenses	499,441	394,657	345,184
Gain on sale of assets	(1,813)	(1,715)	(1,290)
Operating income	616,868	357,164	236,725
Amortization of identifiable intangible assets	74,873	17,619	19,641
Depreciation expense	39,601	30,850	26,658
Capital expenditures	80,957	82,449	43,532
Operating Segments | Electrical Segment
Segment Information
Total assets	985,006	901,025
Revenue	1,499,872	1,260,738	961,889
Cost of services	1,137,957	1,020,335	800,900
Gross profit	361,915	240,403	160,989
Selling, general and administrative expenses	170,155	129,623	99,579
Gain on sale of assets	(1,217)	(587)	(295)
Operating income	192,977	111,367	61,705
Amortization of identifiable intangible assets	22,393	25,785	28,154
Depreciation expense	7,450	6,576	6,211
Capital expenditures	26,850	9,600	4,101
Corporate & Eliminations
Segment Information
Total assets	563,405	224,533
Selling, general and administrative expenses	60,476	50,143	44,581
Operating income	(60,476)	(50,143)	(44,581)
Depreciation expense	1,168	736	683
Capital expenditures	$ 3,264	$ 2,789	$ 726