Segment Information (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2025 USD ($)	Jun. 30, 2024 USD ($)	Jun. 30, 2025 USD ($) segment	Jun. 30, 2024 USD ($)	Dec. 31, 2024 USD ($)
Segment Information
Number of reportable segments | segment			2
Total assets	$ 5,063,729		$ 5,063,729		$ 4,711,088
Revenue	2,173,319	$ 1,810,290	4,004,605	$ 3,347,306
Cost of services	1,663,422	1,446,694	3,091,292	2,686,347
Gross profit	509,897	363,596	913,313	660,959
Selling, general and administrative expenses	210,466	179,537	405,340	342,260
Gain on sale of assets	(442)	(611)	(998)	(1,431)
Operating income	299,873	184,670	508,971	320,130
Amortization of identifiable intangible assets	19,791	26,890	39,906	50,803
Depreciation expense	14,856	11,790	28,866	23,044
Capital expenditures	31,273	23,384	53,481	48,336
Operating Segments | Mechanical Segment
Segment Information
Total assets	3,633,522		3,633,522		3,162,677
Revenue	1,638,672	1,451,679	3,040,887	2,636,688
Cost of services	1,264,066	1,172,707	2,361,762	2,140,004
Gross profit	374,606	278,972	679,125	496,684
Selling, general and administrative expenses	137,074	124,628	269,344	235,610
Gain on sale of assets	(371)	(356)	(723)	(930)
Operating income	237,903	154,700	410,504	262,004
Amortization of identifiable intangible assets	14,266	21,365	28,856	39,459
Depreciation expense	12,093	9,705	23,497	18,933
Capital expenditures	24,879	18,227	43,298	38,169
Operating Segments | Electrical Segment
Segment Information
Total assets	1,094,984		1,094,984		985,006
Revenue	534,647	358,611	963,718	710,618
Cost of services	399,356	273,987	729,530	546,343
Gross profit	135,291	84,624	234,188	164,275
Selling, general and administrative expenses	55,235	41,138	99,281	75,018
Gain on sale of assets	(71)	(255)	(275)	(501)
Operating income	80,127	43,741	135,182	89,758
Amortization of identifiable intangible assets	5,525	5,525	11,050	11,344
Depreciation expense	2,458	1,804	4,761	3,524
Capital expenditures	6,093	3,893	9,632	8,272
Corporate & Eliminations
Segment Information
Total assets	335,223		335,223		$ 563,405
Selling, general and administrative expenses	18,157	13,771	36,715	31,632
Operating income	(18,157)	(13,771)	(36,715)	(31,632)
Depreciation expense	305	281	608	587
Capital expenditures	$ 301	$ 1,264	$ 551	$ 1,895