Discontinued Operations And Other Dispositions (Schedule Of Disposal Groups Including Discontinued Operations)(Details) (USD $) In Thousands	Sep. 30, 2011	Dec. 31, 2010
Discontinued Operations And Other Dispositions [Abstract]
Property, plant and equipment, at cost	$ 168,463	$ 165,935
Less: accumulated depreciation	56,923	55,492
Net property, plant and equipment	111,540	110,443
Current assets	12,768	8,858
Regulatory assets	30,685	29,399
Goodwill	12,316	12,316
Other assets	2,418	2,483
Assets of discontinued operations held for sale	169,727	163,499
Long-term debt, excluding current portion	40,307	40,606
Current liabilities	7,741	4,039
Deferred income taxes and investment tax credits	30,110	22,407
Contributions in aid of construction	9,794	9,656
Other liabilities	26,869	26,891
Liabilities of discontinued operations held for sale	114,821	103,599
Net assets	$ 54,906	$ 59,900