Schedule of Restructuring Activities (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015	Dec. 31, 2014
Restructuring Cost and Reserve [Line Items]
Restructuring reserve	$ 172	$ 239	$ 81	$ 281
Restructuring expenses	91	8
Payments for restructuring	0	(50)
Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expenses	100	100
UNITED STATES | Operating Segments [Member] | United States Electrical Construction And Facilities Services [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring reserve	0	239	0	255
Restructuring expenses	0	2
Payments for restructuring	0	(18)
UNITED STATES | Operating Segments [Member] | United States Mechanical Construction And Facilities Services [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring reserve	0	0	0	26
Restructuring expenses	0	6
Payments for restructuring	0	(32)
UNITED STATES | Operating Segments [Member] | United States Building Services [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring reserve	172	0	$ 81	$ 0
Restructuring expenses	91	0
Payments for restructuring	$ 0	$ 0