Schedule of Restructuring Activities (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013	Dec. 31, 2012
Restructuring Cost and Reserve [Line Items]
Restructuring reserve	$ 174	$ 396	$ 174	$ 396	$ 194	$ 53
Restructuring expenses	398	601	799	652
Payments for restructuring			(819)	(309)
Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expenses	400	500	580	600
Facility Closing [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expenses		100	219	100
Corporate, Non-Segment [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring reserve	0	0	0	0	0	0
Restructuring expenses			300	0
Payments for restructuring			(300)	0
Corporate, Non-Segment [Member] | Employee Severance [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expenses			0
Corporate, Non-Segment [Member] | Facility Closing [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expenses			300
UNITED STATES | Operating Segments [Member] | United States Electrical Construction And Facilities Services [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring reserve	0	35	0	35	30	53
Restructuring expenses			375	0
Payments for restructuring			(405)	(18)
UNITED STATES | Operating Segments [Member] | United States Mechanical Construction And Facilities Services [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring reserve	174	344	174	344	164	0
Restructuring expenses			124	473
Payments for restructuring			(114)	(129)
UNITED STATES | Operating Segments [Member] | United States Building Services [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring reserve	0	17	0	17	0	0
Restructuring expenses			0	179
Payments for restructuring			0	(162)
UNITED STATES | Operating Segments [Member] | Employee Severance [Member] | United States Electrical Construction And Facilities Services [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expenses			375
UNITED STATES | Operating Segments [Member] | Employee Severance [Member] | United States Mechanical Construction And Facilities Services [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expenses			205
UNITED STATES | Operating Segments [Member] | Employee Severance [Member] | United States Building Services [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expenses			0
UNITED STATES | Operating Segments [Member] | Facility Closing [Member] | United States Electrical Construction And Facilities Services [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expenses			0
UNITED STATES | Operating Segments [Member] | Facility Closing [Member] | United States Mechanical Construction And Facilities Services [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expenses			(81)
UNITED STATES | Operating Segments [Member] | Facility Closing [Member] | United States Building Services [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring expenses			$ 0