Goodwill Schedule of Goodwill Allocated to Reporting Segments (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013
Goodwill [Roll Forward]
Goodwill before impairment, at beginning of period			$ 1,318,271
Accumulated impairment losses, at beginning of period			(769,693)
Goodwill, net, at beginning of period			548,578
Goodwill impairment	0	0	(977)	0	(173,200)
Effect of change in exchange rates			(31,960)
Goodwill before impairment, at end of period	1,231,679		1,231,679		1,318,271
Accumulated impairment losses, at end of period	(716,038)		(716,038)		(769,693)
Goodwill, net, at end of period	515,641		515,641		548,578
Electricity Operating Segment [Member]
Goodwill [Roll Forward]
Goodwill before impairment, at beginning of period			493,610
Accumulated impairment losses, at beginning of period			(433,378)
Goodwill, net, at beginning of period			60,232
Goodwill impairment			(977)
Effect of change in exchange rates			(2,408)
Goodwill before impairment, at end of period	463,550		463,550
Accumulated impairment losses, at end of period	(406,703)		(406,703)
Goodwill, net, at end of period	56,847		56,847
Gas Operating Segment [Member]
Goodwill [Roll Forward]
Goodwill before impairment, at beginning of period			394,878
Accumulated impairment losses, at beginning of period			0
Goodwill, net, at beginning of period			394,878
Goodwill impairment			0
Effect of change in exchange rates			(24,211)
Goodwill before impairment, at end of period	370,667		370,667
Accumulated impairment losses, at end of period	0		0
Goodwill, net, at end of period	370,667		370,667
Water Operating Segment [Member]
Goodwill [Roll Forward]
Goodwill before impairment, at beginning of period			429,783
Accumulated impairment losses, at beginning of period			(336,315)
Goodwill, net, at beginning of period			93,468
Goodwill impairment			0
Effect of change in exchange rates			(5,341)
Goodwill before impairment, at end of period	397,462		397,462
Accumulated impairment losses, at end of period	(309,335)		(309,335)
Goodwill, net, at end of period	$ 88,127		$ 88,127