Business and Organization (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Business and Organization
Revenue	$ 428,760	$ 410,565	$ 1,242,240	$ 1,196,679
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			$ 930,694
Percentage of revenue attributable to services			75.00%
Plumbing
Business and Organization
Revenue			$ 181,824
Percentage of revenue attributable to services			15.00%
Building Automation Control Systems
Business and Organization
Revenue			$ 68,042
Percentage of revenue attributable to services			5.00%
Other
Business and Organization
Revenue			$ 61,680
Percentage of revenue attributable to services			5.00%