Other Retirement Plans Other Retirement Plans (Narrative) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012
Multiemployer Plans [Line Items]
Multiemployer plans, underfunded status, description	A multi-employer plan that is so underfunded as to be in “endangered” or “critical” status is required to adopt a funding improvement plan (“FIP”) or a rehabilitation plan (“RP”), which, among other actions, could include decreased benefits and increased contributions. These actions are intended to improve their funding status over a period of years. If a pension fund is in critical status, a participating employer must pay an automatic surcharge in addition to contributions otherwise required under the collective bargaining agreement (“CBA”).  With some exceptions, the surcharge is equal to 5% of required contributions for the initial critical year, and 10% for each succeeding plan year in which the plan remains in critical status. The surcharge ceases on the effective date of a CBA (or other agreement) that includes contribution and benefit terms consistent with the rehabilitation plan.
Multiemployer plans, employees increase (decrease), description	In addition, the number of union employees employed at any given time, and the plans in which they may participate, varies depending upon the location and number of ongoing projects at a given time and the need for union resources in connection with those projects.
Multiemployer plans, withdrawal liability	$ 6.4
EC Source [Member]
Multiemployer Plans [Line Items]
Multiemployer plans, business combination or divestiture, description	The average number of employees covered under multi-employer plans in which the Company participates increased in 2011 due to the acquisition of EC Source.
Multiemployer Plans, Pension [Member]
Multiemployer Plans [Line Items]
Multiemployer plans, underfunded status, description	The Pension Protection Act requires that underfunded pension plans improve their funding ratios within prescribed intervals based on the level of their underfunding. In addition, if a multi-employer defined benefit plan fails to satisfy certain minimum funding requirements, the Internal Revenue Service may impose on the employers contributing to such plan a nondeductible excise tax of 5% on the amount of the accumulated funding deficiency.
Multiemployer Plans, Pension [Member] | Teamsters National Pipeline Pension Fund [Member]
Multiemployer Plans [Line Items]
Multiemployer plans, information not available	Information not available as of December 31, 2012. The Teamsters National Pipeline Pension Fund was established in 2012.
Multiemployer Plans, Pension [Member] | Central States Southeast And Southwest Areas Pension Fund [Member]
Multiemployer Plans [Line Items]
Multiemployer plans, withdrawal liability	$ 6.4