Financial Instruments And Investments (Company's Decommissioning Trust Funds And Investments In Debt Securities) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Decommissioning Fund Investments
Financial Instruments and Investments [Line Items]
Available-for-sale Securities	$ 214,095	$ 187,053
Decommissioning Fund Investments | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Financial Instruments and Investments [Line Items]
Available-for-sale Securities	154,077	120,863
Decommissioning Fund Investments | Significant Other Observable Inputs (Level 2)
Financial Instruments and Investments [Line Items]
Available-for-sale Securities	60,018	66,190
Decommissioning Fund Investments | Significant Unobservable Inputs (Level 3)
Financial Instruments and Investments [Line Items]
Available-for-sale Securities	0	0
Debt Securities
Financial Instruments and Investments [Line Items]
Investments in Debt Securities	1,555	1,295	1,120
Debt Securities | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Financial Instruments and Investments [Line Items]
Investments in Debt Securities	0	0
Debt Securities | Significant Other Observable Inputs (Level 2)
Financial Instruments and Investments [Line Items]
Investments in Debt Securities	0	0
Debt Securities | Significant Unobservable Inputs (Level 3)
Financial Instruments and Investments [Line Items]
Investments in Debt Securities	1,555	1,295
Debt Securities | Decommissioning Fund Investments
Financial Instruments and Investments [Line Items]
Available-for-sale Securities	85,256	90,575
Debt Securities | Decommissioning Fund Investments | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Financial Instruments and Investments [Line Items]
Available-for-sale Securities	25,238	24,385
Debt Securities | Decommissioning Fund Investments | Significant Other Observable Inputs (Level 2)
Financial Instruments and Investments [Line Items]
Available-for-sale Securities	60,018	66,190
Debt Securities | Decommissioning Fund Investments | Significant Unobservable Inputs (Level 3)
Financial Instruments and Investments [Line Items]
Available-for-sale Securities	0	0
U.S. Government Bonds | Decommissioning Fund Investments
Financial Instruments and Investments [Line Items]
Available-for-sale Securities	25,238	24,385
U.S. Government Bonds | Decommissioning Fund Investments | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Financial Instruments and Investments [Line Items]
Available-for-sale Securities	25,238	24,385
U.S. Government Bonds | Decommissioning Fund Investments | Significant Other Observable Inputs (Level 2)
Financial Instruments and Investments [Line Items]
Available-for-sale Securities	0	0
U.S. Government Bonds | Decommissioning Fund Investments | Significant Unobservable Inputs (Level 3)
Financial Instruments and Investments [Line Items]
Available-for-sale Securities	0	0
Collateralized Mortgage Backed Securities | Decommissioning Fund Investments
Financial Instruments and Investments [Line Items]
Available-for-sale Securities	17,794	19,497
Collateralized Mortgage Backed Securities | Decommissioning Fund Investments | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Financial Instruments and Investments [Line Items]
Available-for-sale Securities	0	0
Collateralized Mortgage Backed Securities | Decommissioning Fund Investments | Significant Other Observable Inputs (Level 2)
Financial Instruments and Investments [Line Items]
Available-for-sale Securities	17,794	19,497
Collateralized Mortgage Backed Securities | Decommissioning Fund Investments | Significant Unobservable Inputs (Level 3)
Financial Instruments and Investments [Line Items]
Available-for-sale Securities	0	0
Municipal Bonds | Decommissioning Fund Investments
Financial Instruments and Investments [Line Items]
Available-for-sale Securities	28,851	33,863
Municipal Bonds | Decommissioning Fund Investments | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Financial Instruments and Investments [Line Items]
Available-for-sale Securities	0	0
Municipal Bonds | Decommissioning Fund Investments | Significant Other Observable Inputs (Level 2)
Financial Instruments and Investments [Line Items]
Available-for-sale Securities	28,851	33,863
Municipal Bonds | Decommissioning Fund Investments | Significant Unobservable Inputs (Level 3)
Financial Instruments and Investments [Line Items]
Available-for-sale Securities	0	0
Corporate Debt Securities | Decommissioning Fund Investments
Financial Instruments and Investments [Line Items]
Available-for-sale Securities	13,373	12,830
Corporate Debt Securities | Decommissioning Fund Investments | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Financial Instruments and Investments [Line Items]
Available-for-sale Securities	0	0
Corporate Debt Securities | Decommissioning Fund Investments | Significant Other Observable Inputs (Level 2)
Financial Instruments and Investments [Line Items]
Available-for-sale Securities	13,373	12,830
Corporate Debt Securities | Decommissioning Fund Investments | Significant Unobservable Inputs (Level 3)
Financial Instruments and Investments [Line Items]
Available-for-sale Securities	0	0
Equity Securities | Decommissioning Fund Investments
Financial Instruments and Investments [Line Items]
Available-for-sale Securities	106,113	76,813
Equity Securities | Decommissioning Fund Investments | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Financial Instruments and Investments [Line Items]
Available-for-sale Securities	106,113	76,813
Equity Securities | Decommissioning Fund Investments | Significant Other Observable Inputs (Level 2)
Financial Instruments and Investments [Line Items]
Available-for-sale Securities	0	0
Equity Securities | Decommissioning Fund Investments | Significant Unobservable Inputs (Level 3)
Financial Instruments and Investments [Line Items]
Available-for-sale Securities	0	0
Equity Mutual Funds | Decommissioning Fund Investments
Financial Instruments and Investments [Line Items]
Available-for-sale Securities	16,802	15,194
Equity Mutual Funds | Decommissioning Fund Investments | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Financial Instruments and Investments [Line Items]
Available-for-sale Securities	16,802	15,194
Equity Mutual Funds | Decommissioning Fund Investments | Significant Other Observable Inputs (Level 2)
Financial Instruments and Investments [Line Items]
Available-for-sale Securities	0	0
Equity Mutual Funds | Decommissioning Fund Investments | Significant Unobservable Inputs (Level 3)
Financial Instruments and Investments [Line Items]
Available-for-sale Securities	0	0
Cash and Cash Equivalents | Decommissioning Fund Investments
Financial Instruments and Investments [Line Items]
Available-for-sale Securities	5,924	4,471
Cash and Cash Equivalents | Decommissioning Fund Investments | Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]
Financial Instruments and Investments [Line Items]
Available-for-sale Securities	5,924	4,471
Cash and Cash Equivalents | Decommissioning Fund Investments | Significant Other Observable Inputs (Level 2)
Financial Instruments and Investments [Line Items]
Available-for-sale Securities	0	0
Cash and Cash Equivalents | Decommissioning Fund Investments | Significant Unobservable Inputs (Level 3)
Financial Instruments and Investments [Line Items]
Available-for-sale Securities	$ 0	$ 0