Acquisitions (2013 Acquisitions - Big Country) (Narrative) (Details) - Big Country [Member] - USD ($) $ in Millions		12 Months Ended
	May. 01, 2013	Dec. 31, 2015
Business Combinations [Line Items]
Business combinations, effective date		May 01, 2013
Business combinations, percentage of voting interests acquired		100.00%
Business combinations, name of acquired entity		Big Country Energy Services, Inc. and its affiliated operating companies (collectively, “Big Country”)
Business combinations, description of acquired entity		a North American oil and gas pipeline and facility construction services company, headquartered in Calgary, Alberta, Canada
Earn-Out Arrangements [Member]
Business Combinations [Line Items]
Business combinations, contingent consideration, earn-out period (in years)		5 years
Canadian Dollars [Member]
Business Combinations [Line Items]
Business combinations, payments in cash (in dollars)	$ 103.5
Canadian Dollars [Member] | Earn-Out Arrangements [Member]
Business Combinations [Line Items]
Business combinations, contingent consideration, fair value of earn-out (in dollars)		$ 9.0