Business and Organization (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Business and Organization
Revenue	$ 427,538	$ 416,567	$ 813,480	$ 786,114
Percentage of revenue attributable to services			100.00%
Installation of systems in newly constructed facilities
Business and Organization
Percentage of revenue attributable to services			40.00%
Maintenance, repair and replacement services
Business and Organization
Percentage of revenue attributable to services			60.00%
HVAC
Business and Organization
Revenue			$ 610,110
Percentage of revenue attributable to services			75.00%
Plumbing
Business and Organization
Revenue			$ 122,022
Percentage of revenue attributable to services			15.00%
Building Automation Control Systems
Business and Organization
Revenue			$ 48,809
Percentage of revenue attributable to services			6.00%
Other
Business and Organization
Revenue			$ 32,539
Percentage of revenue attributable to services			4.00%