Goodwill and Identifiable Intangible Assets, Net - Changes in Carrying Amount of Goodwill (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 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)	25,645	19,675
Balance at end of period	637,434	611,789
Mechanical Services Segment
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 Services Industry
Changes in the carrying amount of goodwill
Balance at beginning of year	247,860	230,794
Acquisitions and purchase price adjustments (See Note 5)	25,645	17,066
Balance at end of period	$ 273,505	$ 247,860