Business and Organization (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Business and Organization
Revenue	$ 380,588	$ 385,942
Percentage of revenue attributable to services	100.00%
Installation of systems in newly constructed facilities
Business and Organization
Percentage of revenue attributable to services	39.00%
Maintenance, repair and replacement services
Business and Organization
Percentage of revenue attributable to services	61.00%
HVAC
Business and Organization
Revenue	$ 270,217
Percentage of revenue attributable to services	71.00%
Plumbing
Business and Organization
Revenue	$ 68,506
Percentage of revenue attributable to services	18.00%
Building Automation Control Systems
Business and Organization
Revenue	$ 22,835
Percentage of revenue attributable to services	6.00%
Other
Business and Organization
Revenue	$ 19,030
Percentage of revenue attributable to services	5.00%