Revenue from Contracts with Customers - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Disaggregation of Revenue
Revenue	$ 885,216	$ 669,761
Percentage of revenue from contract with customer (as a percent)	100.00%	100.00%
Industrial
Disaggregation of Revenue
Revenue	$ 410,184	$ 269,583
Percentage of revenue from contract with customer (as a percent)	46.30%	40.30%
Education
Disaggregation of Revenue
Revenue	$ 89,446	$ 92,457
Percentage of revenue from contract with customer (as a percent)	10.10%	13.80%
Office Buildings
Disaggregation of Revenue
Revenue	$ 75,115	$ 78,996
Percentage of revenue from contract with customer (as a percent)	8.50%	11.80%
Healthcare
Disaggregation of Revenue
Revenue	$ 134,795	$ 95,091
Percentage of revenue from contract with customer (as a percent)	15.20%	14.20%
Government
Disaggregation of Revenue
Revenue	$ 57,465	$ 43,165
Percentage of revenue from contract with customer (as a percent)	6.50%	6.40%
Retail, Restaurants and Entertainment
Disaggregation of Revenue
Revenue	$ 65,582	$ 44,576
Percentage of revenue from contract with customer (as a percent)	7.40%	6.70%
Multi-Family and Residential
Disaggregation of Revenue
Revenue	$ 24,442	$ 24,660
Percentage of revenue from contract with customer (as a percent)	2.80%	3.70%
Other
Disaggregation of Revenue
Revenue	$ 28,187	$ 21,233
Percentage of revenue from contract with customer (as a percent)	3.20%	3.10%
New Construction
Disaggregation of Revenue
Revenue	$ 429,418	$ 302,061
Percentage of revenue from contract with customer (as a percent)	48.50%	45.10%
Existing Building Construction
Disaggregation of Revenue
Revenue	$ 259,285	$ 216,601
Percentage of revenue from contract with customer (as a percent)	29.30%	32.30%
Service Projects
Disaggregation of Revenue
Revenue	$ 76,252	$ 60,060
Percentage of revenue from contract with customer (as a percent)	8.60%	9.00%
Service Calls, Maintenance and Monitoring
Disaggregation of Revenue
Revenue	$ 120,261	$ 91,039
Percentage of revenue from contract with customer (as a percent)	13.60%	13.60%
Mechanical Services
Disaggregation of Revenue
Revenue	$ 682,511	$ 565,620
Percentage of revenue from contract with customer (as a percent)	77.10%	84.50%
Electrical Services
Disaggregation of Revenue
Revenue	$ 202,705	$ 104,141
Percentage of revenue from contract with customer (as a percent)	22.90%	15.50%