Concentrations of Risk (Tables)

3 Months Ended

Mar. 31, 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 March 31,
	2013	2012
Customer:
AT&T	18%	19%
DIRECTV®	16%	20%
Enbridge, Inc.	12%	—%

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 March 31,
	2013	2012
Revenue from top ten customers	69%	71%