Financial Instruments And Investments (Unrecognized Gross Unrealized Gains And The Fair Value) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Schedule of Available-for-sale Securities [Line Items]
Fair Value	$ 167,304	$ 158,634
Unrealized Gains	35,789	29,039
Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value	63,596	65,759
Unrealized Gains	3,983	4,379
Collateralized Mortgage Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value	16,905	17,289
Unrealized Gains	917	1,036
U.S. Government Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value	12,214	13,295
Unrealized Gains	608	678
Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value	22,932	22,797
Unrealized Gains	1,484	1,531
Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value	11,545	12,378
Unrealized Gains	974	1,134
Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value	83,274	73,210
Unrealized Gains	29,475	22,839
Mutual Funds - Equity [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value	15,718	15,194
Unrealized Gains	2,331	1,821
Cash and Cash Equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair Value	4,716	4,471
Unrealized Gains	$ 0	$ 0

Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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

-Publisher FASB

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

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Reference 5: http://www.xbrl.org/2003/role/presentationRef

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 6: http://www.xbrl.org/2003/role/presentationRef

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 8: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 9: http://www.xbrl.org/2003/role/presentationRef

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 10: http://www.xbrl.org/2003/role/presentationRef

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details

- Definition

This item represents the gross unrealized gains for securities, at a point in time, which are categorized neither as held-to-maturity nor trading securities.

+ References+ Details