Goodwill and Identifiable Intangible Assets, Net - Changes in Carrying Amount of Goodwill (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2023	Dec. 31, 2022
Changes in the carrying amount of goodwill
Balance at beginning of year	$ 611,789	$ 592,114
Acquisitions and purchase price adjustments (See Note 5)	25,698	19,675
Balance at end of period	637,487	611,789
Mechanical Segment [Member]
Changes in the carrying amount of goodwill
Balance at beginning of year	363,929	361,320
Acquisitions and purchase price adjustments (See Note 5)		2,609
Balance at end of period	363,929	363,929
Electrical Segment [Member]
Changes in the carrying amount of goodwill
Balance at beginning of year	247,860	230,794
Acquisitions and purchase price adjustments (See Note 5)	25,698	17,066
Balance at end of period	$ 273,558	$ 247,860