Business and Organization (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Business and Organization
Revenue	$ 392,100	$ 428,760	$ 427,538	$ 385,942	$ 383,840	$ 410,565	$ 416,567	$ 369,547	$ 1,634,340	$ 1,580,519	$ 1,410,795
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									$ 1,225,755
Percentage of revenue attributable to services									75.00%
Plumbing
Business and Organization
Revenue									$ 245,151
Percentage of revenue attributable to services									15.00%
Building Automation Control Systems
Business and Organization
Revenue									$ 98,060
Percentage of revenue attributable to services									6.00%
Other
Business and Organization
Revenue									$ 65,374
Percentage of revenue attributable to services									4.00%