Other Charges - Restructuring Reserve (Details) - Equipment and Facility Lease Abandonment [Member] $ in Thousands	3 Months Ended
	Mar. 31, 2016 USD ($)
Restructuring Reserve [Roll Forward]
Accrued cost at December 31, 2015	$ 8,400
Costs recognized	3,414
Cash payments	(1,222)
Non-cash charges	429
Change in estimates	(119)
Accrued cost at March 31, 2016	10,902
Continuing Operations [Member] | Operating Segments [Member] | Oil & Gas [Member]
Restructuring Reserve [Roll Forward]
Accrued cost at December 31, 2015	1,434
Costs recognized	1,013
Cash payments	(238)
Non-cash charges	0
Change in estimates	(119)
Accrued cost at March 31, 2016	2,090
Continuing Operations [Member] | Operating Segments [Member] | Canada Segment [Member]
Restructuring Reserve [Roll Forward]
Accrued cost at December 31, 2015	181
Costs recognized	0
Cash payments	(22)
Non-cash charges	0
Change in estimates	0
Accrued cost at March 31, 2016	159
Continuing Operations [Member] | Operating Segments [Member] | Utility T&D [Member]
Restructuring Reserve [Roll Forward]
Accrued cost at December 31, 2015	626
Costs recognized	0
Cash payments	(51)
Non-cash charges	0
Change in estimates	0
Accrued cost at March 31, 2016	575
Continuing Operations [Member] | Corporate [Member]
Restructuring Reserve [Roll Forward]
Accrued cost at December 31, 2015	4,163
Costs recognized	2,401
Cash payments	(326)
Non-cash charges	45
Change in estimates	0
Accrued cost at March 31, 2016	6,283
Discontinued Operations [Member]
Restructuring Reserve [Roll Forward]
Accrued cost at December 31, 2015	1,996
Costs recognized	0
Cash payments	(585)
Non-cash charges	384
Change in estimates	0
Accrued cost at March 31, 2016	$ 1,795