Quarterly Information (Unaudited) (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended					12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Quarterly Financial Information [Line Items]
Goodwill and intangible asset impairment						$ 78,625	$ 0	$ 0
General and administrative expenses (in dollars)						265,910	238,305	$ 215,402
Foreign Tax Authority [Member] | Alberta
Quarterly Financial Information [Line Items]
Income tax expense, adjustment resulting from tax law change			$ 2,800
Pacer [Member]
Quarterly Financial Information [Line Items]
Goodwill and intangible asset impairment	$ 78,600
Corporate [Member]
Quarterly Financial Information [Line Items]
Goodwill and intangible asset impairment						78,600
Corporate [Member] | Audit Committee Investigation [Member]
Quarterly Financial Information [Line Items]
General and administrative expenses (in dollars)	2,800	$ 4,100	7,500	$ 3,000		16,500
Communications [Member]
Quarterly Financial Information [Line Items]
Business combinations, acquisition integration costs		1,200	7,800	8,800	$ 5,300	17,800	$ 5,300
Power Generation and Industrial [Member] | Contracts Accounted for under Percentage of Completion [Member] | Canadian Dollars [Member]
Quarterly Financial Information [Line Items]
Project losses		3,800	$ 1,600	16,000		21,400
Other [Member]
Quarterly Financial Information [Line Items]
Unrealized recognized losses on interest rate swaps, unconsolidated affiliates						4,400
Other [Member] | Waha JVs [Member] | Interest Rate Swap [Member]
Quarterly Financial Information [Line Items]
Unrealized recognized losses on interest rate swaps, unconsolidated affiliates	4,400					4,400
Other [Member] | Contracts Accounted for under Percentage of Completion [Member] | Canadian Dollars [Member] | Corporate Joint Venture [Member] | Pacer [Member]
Quarterly Financial Information [Line Items]
Project losses	$ 8,000	2,800		$ 5,500		16,300
Electrical Transmission [Member] | PPL [Member] | Resolved Litigation [Member]
Quarterly Financial Information [Line Items]
Court mandated remediation settlement charge (in dollars)						12,200
Electrical Transmission [Member] | PPL [Member] | Resolved Litigation [Member] | Other Expense [Member]
Quarterly Financial Information [Line Items]
Court mandated remediation settlement charge (in dollars)		$ 12,200
Electrical Transmission [Member] | Contracts Accounted for under Percentage of Completion [Member]
Quarterly Financial Information [Line Items]
Project losses						$ 14,000