Segment Information (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2025 USD ($) segment	Mar. 31, 2024 USD ($)	Dec. 31, 2024 USD ($)
Segment Information
Number of reportable segments | segment	2
Total assets	$ 4,569,218		$ 4,711,088
Revenue	1,831,286	$ 1,537,016
Cost of services	1,427,870	1,239,653
Gross profit	403,416	297,363
Selling, general and administrative expenses	194,874	162,723
Gain on sale of assets	(556)	(820)
Operating income	209,098	135,460
Amortization of identifiable intangible assets	20,115	23,913
Depreciation expense	14,010	11,254
Capital expenditures	22,208	24,952
Operating Segments | Mechanical Segment
Segment Information
Total assets	3,326,612		3,162,677
Revenue	1,402,215	1,185,009
Cost of services	1,097,696	967,297
Gross profit	304,519	217,712
Selling, general and administrative expenses	132,270	110,982
Gain on sale of assets	(352)	(574)
Operating income	172,601	107,304
Amortization of identifiable intangible assets	14,590	18,094
Depreciation expense	11,404	9,228
Capital expenditures	18,419	19,942
Operating Segments | Electrical Segment
Segment Information
Total assets	1,031,571		985,006
Revenue	429,071	352,007
Cost of services	330,174	272,356
Gross profit	98,897	79,651
Selling, general and administrative expenses	44,046	33,880
Gain on sale of assets	(204)	(246)
Operating income	55,055	46,017
Amortization of identifiable intangible assets	5,525	5,819
Depreciation expense	2,303	1,720
Capital expenditures	3,539	4,379
Corporate & Eliminations
Segment Information
Total assets	211,035		$ 563,405
Selling, general and administrative expenses	18,558	17,861
Operating income	(18,558)	(17,861)
Depreciation expense	303	306
Capital expenditures	$ 250	$ 631