Concentrations of Risk (Tables)

6 Months Ended

Jun. 30, 2013

Concentration Risk [Line Items]

Schedule of Major Customer Revenue Concentration

Revenue concentration information for significant customers, as a percent of total consolidated revenue from continuing operations, is as follows:

	For the Three Months Ended June 30,		For the Six Months Ended June 30,
	2013	2012	2013	2012
Customer:
AT&T	21%	17%	20%	18%
DIRECTV®	15%	15%	15%	17%
Enbridge, Inc.	9%	—%	10%	—%

The Company's relationship with AT&T is based upon master service agreements, other service agreements and construction/installation contracts for both AT&T's wireless and wireline infrastructure businesses. Revenue from AT&T is included in the Communications segment.

The Company's relationship with DIRECTV® is based upon an agreement to provide installation and maintenance services for DIRECTV®. Revenue from DIRECTV® is included in the Communications segment.

The Company's relationship with Enbridge, Inc. is based upon a construction contract for natural gas pipelines. Revenue from Enbridge, Inc. is included in the Oil and Gas segment.

Ten Largest Customers [Member]

Concentration Risk [Line Items]

Schedule of Major Customer Revenue Concentration

Revenue concentration information for the Company's top ten customers, as a percent of total consolidated revenue from continuing operations, is as follows:

	For the Three Months Ended June 30,		For the Six Months Ended June 30,
	2013	2012	2013	2012
Revenue from top ten customers	70%	69%	68%	68%