Revenue from Contracts with Customers (Tables)

9 Months Ended

Sep. 30, 2021

Revenue from Contract with Customers

Schedule of disaggregation of revenue

See details in the following tables (dollars in thousands):

	Three Months Ended September 30,								Nine Months Ended September 30,
Revenue by Service Provided	2021				2020				2021				2020
Mechanical Services	$	690,680	82.8	%	$	625,660	87.6	%	$	1,868,096	84.2	%	$	1,823,117	84.5	%
Electrical Services		143,216	17.2	%		88,439	12.4	%		349,456	15.8	%		334,581	15.5	%
Total	$	833,896	100.0	%	$	714,099	100.0	%	$	2,217,552	100.0	%	$	2,157,698	100.0	%

	Three Months Ended September 30,								Nine Months Ended September 30,
Revenue by Type of Customer	2021				2020				2021				2020
Industrial	$	379,605	45.5	%	$	268,651	37.6	%	$	960,263	43.3	%	$	844,719	39.1	%
Education		115,536	13.9	%		135,992	19.0	%		300,374	13.5	%		375,580	17.4	%
Office Buildings		77,806	9.3	%		81,183	11.4	%		229,816	10.4	%		232,349	10.8	%
Healthcare		101,446	12.2	%		86,061	12.1	%		292,541	13.2	%		281,370	13.0	%
Government		40,268	4.8	%		40,631	5.7	%		125,939	5.7	%		119,444	5.5	%
Retail, Restaurants and Entertainment		62,365	7.5	%		64,212	9.0	%		155,874	7.0	%		190,043	8.8	%
Multi-Family and Residential		29,741	3.6	%		21,776	3.0	%		82,742	3.7	%		61,062	2.8	%
Other		27,129	3.2	%		15,593	2.2	%		70,003	3.2	%		53,131	2.6	%
Total	$	833,896	100.0	%	$	714,099	100.0	%	$	2,217,552	100.0	%	$	2,157,698	100.0	%
	Three Months Ended September 30,								Nine Months Ended September 30,
Revenue by Activity Type	2021				2020				2021				2020
New Construction	$	397,446	47.6	%	$	310,000	43.4	%	$	1,029,397	46.4	%	$	1,034,833	48.0	%
Existing Building Construction		250,893	30.1	%		235,798	33.0	%		682,811	30.8	%		668,067	30.9	%
Service Projects		75,525	9.1	%		69,162	9.7	%		201,848	9.1	%		179,188	8.3	%
Service Calls, Maintenance and Monitoring		110,032	13.2	%		99,139	13.9	%		303,496	13.7	%		275,610	12.8	%
Total	$	833,896	100.0	%	$	714,099	100.0	%	$	2,217,552	100.0	%	$	2,157,698	100.0	%

Schedule of contract assets and liabilities

The following table presents the changes in contract assets and contract liabilities (in thousands):

	Nine Months Ended September 30,					Year Ended December 31,
	2021				2020
	Contract		Contract		Contract		Contract
	Assets		Liabilities		Assets		Liabilities
Balance at beginning of period	$	18,622	$	226,237	$	2,736	$	166,918
Change due to acquisitions / disposals		2,378		18,084		9,509		39,885
Change related to credit allowance		45		—		(79)		—
Other changes in the period		(6,073)		257		6,456		19,434
Balance at end of period	$	14,972	$	244,578	$	18,622	$	226,237