Business Segment Data - Summary of Operating Income (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Segment Reporting Information [Line Items]
Operating income (loss)	$ 53,709	$ 50,091	$ 143,902	$ 139,619
Interest expense	2,851	4,596	8,823	13,483
Other income	1,071	1,208	3,683	2,705
Income before income taxes and income from equity method investments	51,929	46,703	138,762	128,841
Operating segments
Segment Reporting Information [Line Items]
Operating income (loss)	60,201	54,091	160,853	151,582
Other reconciling items
Segment Reporting Information [Line Items]
Operating income (loss)	(6,492)	(4,000)	(16,951)	(11,963)
Electrical & Mechanical | Operating segments
Segment Reporting Information [Line Items]
Operating income (loss)	34,943	31,076	100,771	100,268
Interest expense	(54)	1,391	117	4,645
Transmission & Distribution | Operating segments
Segment Reporting Information [Line Items]
Operating income (loss)	25,258	23,015	60,082	51,314
Interest expense	$ 982	$ 1,367	$ 3,030	$ 3,239