Accounting For Income Taxes (Schedule Of Recovery Of Deferred Income Tax Liabilities) (Details) (Imported) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Income Tax Disclosure [Abstract]
Regulatory assets for deferred income taxes	$ 79,406	$ 84,576

Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences derived regulatory assets and liabilities.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 50

-Paragraph 6

-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32621-109319

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 25

-Paragraph 20

-URI http://asc.fasb.org/extlink&oid=6969291&loc=d3e28680-109314

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 740

-SubTopic 10

-Section 50

-Paragraph 8

-URI http://asc.fasb.org/extlink&oid=6907707&loc=d3e32632-109319

Name:	us-gaap_DeferredTaxAssetsRegulatoryAssetsAndLiabilities
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant