Financial Instruments And Investments (Contractual Year For Maturity Of Available-For-Sale Securities ) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2012 years
Schedule of Available-for-sale Securities [Line Items]
Contractual Maturity Due For, Mortgaged Backed Securities	10
Municipal Debt Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Total	34,868
2012	999
2013 through 2016	11,698
2017 through 2021	14,977
2022 and Beyond	7,194
Corporate Debt Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Total	12,799
2012	0
2013 through 2016	3,692
2017 through 2021	5,517
2022 and Beyond	3,590
U.S. Government Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Total	17,139
2012	1,209
2013 through 2016	4,272
2017 through 2021	7,868
2022 and Beyond	3,790
Minimum
Schedule of Available-for-sale Securities [Line Items]
Debt Instrument, Expected Weighted Average Maturity Year	3
Maximum
Schedule of Available-for-sale Securities [Line Items]
Debt Instrument, Expected Weighted Average Maturity Year	7

This item represents the fair value of debt securities which are expected to mature after five years and through ten years from the balance sheet date and which are categorized neither as held-to-maturity nor trading securities.

+ References+ Details

This item represents the fair value of debt securities which are expected to mature after one year and through five years from the balance sheet date and which are categorized neither as held-to-maturity nor trading securities.

+ References+ Details

- Definition

This item represents the fair value of debt securities which are expected to mature within one year of the balance sheet date and which are categorized neither as held-to-maturity nor trading securities.

+ References+ Details

- Definition

For an unclassified balance sheet, total of debt securities categorized neither as held-to-maturity nor trading.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 45

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6871852&loc=d3e26610-111562

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 115

-Paragraph 12

-Subparagraph b

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name FASB Staff Position (FSP)

-Number FAS115-1/124-1

-Paragraph 15D

-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 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 133

-Paragraph 22

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

-Publisher FASB

-Name FASB Staff Position (FSP)

-Number FAS115-1/124-1

-Paragraph 15C

-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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 115

-Paragraph 13

-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 7: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 320

-Section 50

-Paragraph 2

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-URI http://asc.fasb.org/extlink&oid=6957658&loc=d3e62557-112803

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 115

-Paragraph 137

-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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 115

-Paragraph 16

-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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 25

-Paragraph 1

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6379932&loc=d3e22054-111558

+ Details