Goodwill Schedule of Goodwill Allocated to Reporting Segments (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013
Beginning of the Period [Roll Forward]
Goodwill before impairment			$ 1,318,271
Accumulated impairment losses			(769,693)
Goodwill, net			548,578
Goodwill, Impairment Loss	0	0	(977)	0	(173,200)
Effect of change in exchange rates			(6,062)
End of the Period [Roll Forward]
Goodwill before impairment	1,301,772		1,301,772		1,318,271
Accumulated impairment losses	(760,233)		(760,233)		(769,693)
Goodwill, net	541,539		541,539		548,578
Electricity Operating Segment [Member]
Beginning of the Period [Roll Forward]
Goodwill before impairment			493,610
Accumulated impairment losses			(433,378)
Goodwill, net			60,232
Goodwill, Impairment Loss			(977)
Effect of change in exchange rates			(434)
End of the Period [Roll Forward]
Goodwill before impairment	487,903		487,903
Accumulated impairment losses	(429,082)		(429,082)
Goodwill, net	58,821		58,821
Gas Operating Segment [Member]
Beginning of the Period [Roll Forward]
Goodwill before impairment			394,878
Accumulated impairment losses			0
Goodwill, net			394,878
Goodwill, Impairment Loss			0
Effect of change in exchange rates			(4,613)
End of the Period [Roll Forward]
Goodwill before impairment	390,265		390,265
Accumulated impairment losses	0		0
Goodwill, net	390,265		390,265
Water Operating Segment [Member]
Beginning of the Period [Roll Forward]
Goodwill before impairment			429,783
Accumulated impairment losses			(336,315)
Goodwill, net			93,468
Goodwill, Impairment Loss			0
Effect of change in exchange rates			(1,015)
End of the Period [Roll Forward]
Goodwill before impairment	423,604		423,604
Accumulated impairment losses	(331,151)		(331,151)
Goodwill, net	$ 92,453		$ 92,453