Segment Information Information By Segment (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Segment Reporting Information [Line Items]
Revenues	$ 496,454	$ 495,491	$ 1,460,602	$ 1,425,202
Gross profit	150,762	150,084	468,338	449,795
Operating Income (Loss)	16,458	(6,488)	52,924	13,835
Total other income (expense)	(4,421)	(2,859)	(13,966)	(8,837)
Income Before Income Taxes	12,037	(9,347)	38,958	4,998
Electricity Operating Segment [Member]
Segment Reporting Information [Line Items]
Revenues	203,441	216,615	567,414	605,990
Gross profit	45,959	47,637	141,675	155,094
Operating Income (Loss)	(11,196)	(33,756)	(35,412)	(56,923)
Gas Operating Segment [Member]
Segment Reporting Information [Line Items]
Revenues	149,276	143,240	449,707	416,166
Gross profit	53,492	55,303	168,609	156,073
Operating Income (Loss)	23,836	24,472	73,889	62,883
Water Operating Segment [Member]
Segment Reporting Information [Line Items]
Revenues	143,737	135,636	443,481	403,046
Gross profit	51,311	47,144	158,054	138,628
Operating Income (Loss)	19,157	17,225	60,319	45,189
Corporate Unallocated [Member]
Segment Reporting Information [Line Items]
Operating Income (Loss)	$ (15,339)	$ (14,429)	$ (45,872)	$ (37,314)