Goodwill and Identifiable Intangible Assets, Net - Changes in Carrying Amount of Goodwill (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
Mar. 31, 2022	Dec. 31, 2021
Changes in the carrying amount of goodwill
Balance at beginning of year	$ 592,114	$ 464,392
Acquisitions and purchase price adjustments (See Note 5)	1,833	127,722
Balance at end of period	593,947	592,114
Mechanical Services Segment
Changes in the carrying amount of goodwill
Balance at beginning of year	361,320	307,448
Acquisitions and purchase price adjustments (See Note 5)	1,833	52,771
Impact of segment reorganization		1,101
Balance at end of period	363,153	361,320
Electrical Services Industry
Changes in the carrying amount of goodwill
Balance at beginning of year	230,794	156,944
Acquisitions and purchase price adjustments (See Note 5)		74,951
Impact of segment reorganization		(1,101)
Balance at end of period	$ 230,794	$ 230,794

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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Amount of increase in asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized resulting from a business combination.

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Amount of increase (decrease), classified as other, of an asset representing the future economic benefits from other assets acquired in a business combination that are not individually identified and separately recognized.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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