Segments and Related Information (Schedule of Significant Customers, Revenue Concentration Information) (Details) - Customer Concentration Risk [Member] - Revenue [Member]		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
AT&T (including DIRECTV) [Member] | Communications [Member]
Revenue, Significant Customer [Line Items]
Significant customers, percentage of total consolidated revenue	[1]	34.00%	32.00%	33.00%
Energy Transfer Affiliates [Member] | Oil and Gas [Member]
Revenue, Significant Customer [Line Items]
Significant customers, percentage of total consolidated revenue	[2]	27.00%	7.00%	6.00%

[1] The Company’s relationship with AT&T is based upon multiple separate master service agreements, other service agreements and construction/installation contracts for AT&T’s: (i) wireless business; (ii) wireline/fiber business; and (iii) home security and automation businesses; and for DIRECTV® services, is based upon an agreement to provide installation and maintenance services. Revenue from AT&T is included in the Communications segment.

[2] The Company's relationship with Energy Transfer affiliates is based upon various construction contracts for pipeline activities with Energy Transfer Partners L.P., Sunoco Logistics Partners L.P., and their subsidiaries and affiliates, all of which are consolidated by Energy Transfer Equity, L.P. Revenue from Energy Transfer affiliates is included in the Oil and Gas segment.